Nanoco Technologies Ltd. v. Samsung Electronics Co., Ltd. et al

Filing 1

COMPLAINT against Samsung Advanced Institute of Technology, Samsung Display Co., Ltd., Samsung Electronics America, Inc., Samsung Electronics Co., Ltd., Samsung Electronics Co., Ltd. Visual Display Division ( Filing fee $ 400 receipt number 0540-7664317.), filed by Nanoco Technologies Ltd.. (Attachments: # 1 Civil Cover Sheet, # 2 Exhibit 1, # 3 Exhibit 2, # 4 Exhibit 3, # 5 Exhibit 4, # 6 Exhibit 5, # 7 Exhibit 6, # 8 Exhibit 7, # 9 Exhibit 8, # 10 Exhibit 9, # 11 Exhibit 10, # 12 Exhibit 11, # 13 Exhibit 12, # 14 Exhibit 13, # 15 Exhibit 14)(Henry, Claire)

Exhibit 4

USOO8524.365B2

(12) United States Patent

(10) Patent No.:
US 8,524,365 B2
(45) Date of Patent:
*Sep. 3, 2013

O'Brien et al.
(54) PREPARATION OF NANOPARTICLE

(58) Field of Classification Search
None
See application file for complete search history.

MATERLALS

(75) Inventors: Paul O'Brien, High Peak (GB); Nigel
Pickett, Manchester (GB)
(73) Assignee: Nanoco Technologies Ltd. (GB)
(*) Notice:

(56)

References Cited
2,769,838
3,524,771
4,609.689
6,114,038

Subject to any disclaimer, the term of this
patent is extended or adjusted under 35
U.S.C. 154(b) by 0 days.
This patent is Subject to a terminal dis

(Continued)
FOREIGN PATENT DOCUMENTS

claimer.
CN
EP

(21) Appl. No.: 13/267,532
(22) Filed:

U.S. PATENT DOCUMENTS
A
11/1956 Matter et al.
A
8, 1970 Green
A
9, 1986 Schwartz et al.
A
9, 2000 Castro et al.

1394599
1176646

2, 2003
1, 2002

(Continued)

Oct. 6, 2011

OTHER PUBLICATIONS

(65)

Prior Publication Data

US 2012/OO25155A1

Timoshkin, "Hunting for a Single-Source Precursor: Toward
Stoichiometry Controlled CVD of 13-15 composites'. Solid State
Electronics, vol. 47, (2003), pp. 543-548.*

Feb. 2, 2012

Related U.S. Application Data
(63) Continuation of application No. 12/854,611, filed on
Aug. 11, 2010, now Pat. No. 8,062,703, which is a
continuation of application No. 1 1/579,050, filed as
application No. PCT/GB2005/001611 on Apr. 27,
2005, now Pat. No. 7,803,423.

(Continued)
Primary Examiner —Nathan Empie
Assistant Examiner — Lisha Jiang
(74) Attorney, Agent, or Firm — Wong, Cabello, Lutsch,

(30)

(57)

Rutherford & Brucculeri LLP

Foreign Application Priority Data

A method of producing nanoparticles comprises effecting
conversion of a nanoparticle precursor composition to the
material of the nanoparticles. The precursor composition
comprises a first precursor species containing a first ion to be
incorporated into the growing nanoparticles and a separate
second precursor species containing a second ion to be incor
porated into the growing nanoparticles. The conversion is
effected in the presence of a molecular cluster compound
under conditions permitting seeding and growth of the nano
particles.

Apr. 30, 2004 (GB) ................................... O4O9877.8

(51) Int. Cl.
B82B I/O
B82B3/00
C3OB 29/10

ABSTRACT

(2006.01)
(2006.01)
(2006.01)

(52) U.S. Cl.
USPC ........... 428/403; 428/402: 428/668; 428/689:

427/212; 427/214; 427/215; 977/700; 977/773;
977/813; 977/814;977/815;977/824; 977/827;
977/830

23 Claims, 18 Drawing Sheets

Y

\

idgs

O -:

NH

V

is
NH, d-cdc.

Miss

Se

He s

se c sSe

C:Sise- N?
sis ? '-- NHa Sects CS es:sé
w

-St.
w

O

US 8,524.365 B2
Page 2
(56)

References Cited

U.S. PATENT DOCUMENTS
6,207,229 B1

6,221,602
6,261,779
6,322,901
6,326,144

B1
B1
B1
B1
6,333,110 B1
6,379,635
6,423,551
6.426,513
6,607,829

B2
B1
B1
B1

6,660,379 B1
6,699,723 B1

3, 2001 Bawendi et al.

4/2001
7/2001
1 1/2001
12/2001
12/2001
4/2002
7/2002
7/2002
8, 2003

Barbera-guillem et al.
Barbera-guillem et al.
Bawendi et al.
Bawendi et al.

WO

WO-OOf 17642

3, 2000

WO

WO-O2,04527

1, 2002

W.

W933,

3583

WO

WO-03/099708

12/2003

WO
WO
WO
WO

WO-2004/0085.50
WO-2004/033366
WO-2004/065.362
WO-2004/066361

1, 2004
4/2004
8, 2004
8, 2004

Barbera-Guillem

WO

WO-2005/021150

3, 2005

O'Brien et al.
Weiss et al.
Bawendi et al.
Bawendi et al.

WO
WO
WO
WO

WO-2005,106082
WO-2005/123575
WO-2006/001848
WO-2006/017125

11, 2005
12/2005
1, 2006
2, 2006

WO

WO-2006/075974

T 2006

WO

WO-2006/116337

11, 2006

12/2003 Lakowicz et al.
3, 2004 Weiss et al.

6,815,064 B2

11/2004 Treadway et al.

WO

WO-2006,118543

11, 2006

6,855,551 B2

2/2005 Bawendi et al.

WO

WO-2006,134599

12/2006

6,914,264 B2

7/2005 Chen et al.

WO

WO-2007/020416

2, 2007

6,992.202 B1
7,151,047 B2

1/2006 Banger et al.
12/2006 Chan et al.

WO
WO

WO-2007/049052
WO-2007/060591

5/2007

WO
WO
WO

WO-2007/065039
WO-2007/098378
WO-2007/102799

6, 2007
8, 2007
9, 2007

7,235,361 B2
7,264,527 B2
7,544,725 B2

6, 2007 Bawendi et al.
9, 2007 Bawendi et al.
6, 2009 Pickett et al.

5/2007

7,588,828 B2

9/2009 Mushtaq et al.

WO

WO-2008/O13780

1, 2008

7,674,844 B2

3/2010 Pickett et al.

WO

WO-2008/O54874

5, 2008

2003, OO17264 A1
2003/0106488 A1

1/2003 Treadway et al.
6/2003 Huang et al.

WO
WO

WO-2008, 133660
WO-2009/O16354

11, 2008
2, 2009

2003/0148024
2004.0007169
2004.0036130
2004/01 10002
2004/O110347

8, 2003
1/2004
2/2004
6, 2004
6, 2004

WO
WO

WO-2009/040553
WO-2009/106810

4/2009
9, 2009

A1
A1
A1
A1
A1

2004/0178390 A1

Kodas et al.
Ohtsu et al.
Lee et al.
Kim et al.
Yamashita

9, 2004 Whiteford et al.

OTHER PUBLICATIONS

Cumberland et al., “Inorganic Clusters as Single-Source Precursors

2004/0250745 Al

12/2004 Ogura et al.

for Preparation of CdSe, ZnSe, and CdSe/ZnS Nanomaterials”,

2839. A.
2005, 0145853 A1
2006, OO19098 A1

258 Risin et al.
7, 2005 Sato et al.
1/2006 Chan et al.

Chemistry of Materials, vol. 14, (2002), pp. 1576-1574.*
Agger, J.R. et al., Phys, Chem B (1998) 102, p. 345.
Aldana, J. et al. “Photochemical instability of CdSe Nanocrystals

2006, OO61017 A1

3, 2006 Strouse et al.

Coated by Hydrophilic Thiols”. J. Am. Chem. Soc. (2001), 123:

2006, OO68154 A1

3, 2006 Parce et al.

8844-8850.

3.9. 67. A.
2007/0012941 A1

g3. ity al.
eng
1/2007 Cheonet al.

Alivisatos, A.P. "Perspectives on the Physical Chemistry of Semi
ductor
tals. PhvS. Chem.
stor N
Nanocrystals, J. rays them, (1996), 100, pp 13226
(1996), 100, pp.

2007.0034.833 A1

2/2007 Parce et al.

3/2007 Lu et al.

Arici et al., Thin Solid Films 45.1452 (2004) 612-618.

2007, 0104865 A1
2007, 011081.6 A1
2007/0114520 A1

5, 2007 Pickett
5, 2007 Jun et al.
5, 2007 Garditz et al.

Battaglia et al., “Colloidal Two-dimensional Systems: CodSe Quan
tum Shells and Wells.” Angew Chem. (2003) 115:5189.
Bawendi, M.G. The Quantum Mechanics of Larger Semiconductor

2007/O125983 A1

6/2007 Treadway et al.

2007/0059.705 A1

2007/013 1905 A1

2007/0199.109 A1
2007/0202333 A1
2007/0238126 A1

2008. O107911 A1
2008/O112877 A1

2008/O121844 A1
2008.0160306 A1
2008. O190483 A1

-

--

Clusters ("Quantum Dots'), Annu. Rev. Phys. Chem. (1990), 42:

6, 2007 Sato et al.

477-498.

8, 2007 Yi et al.

Berry, C.R. “Structure and Optical Absorption of Agl Microcrystals'.
Phys. Rev. (1967) 161:848-851.
&8

8, 2007 O'Brien et al.
10, 2007 Pickett et al.

5, 2008 Liu et al.
5, 2008 Xiao et al.

5/2008 Jang et al.
7/2008 Mushtaq et al.
8/2008 Carpenter et al.

Bunge, S.D. et al. Growth and morphology of cadmium
chalcogendes: the synthesis of nanorods, tetrapods, and spheres from

CdO and CdCOCCH), J. Mater. Chem. (2003) 13:1705-1709.
Castro et al., Chem, Mater. (2003) 15:3142-3147.
Castro et al., “Synthesis and Characterization of Colloidal CuInS

2008.O220593 A1
2008/0257.201 A1

9, 2008 Pickett et al.
10, 2008 Harris et al.

Nanoparticels from a Molecular Single-Source Precursors.” J. Phys.
Chem. B (2004) 108: 12429.

2008/0264479 A1
2009/O139574 A1
2009, 0212258 A1

10/2008 Harris et al.
6/2009 Pickett etet al.
al.
8, 2009 Mccairn

Chun et al. Thin Solid Films 480-48 (2005) 46-49.
Contreraset al., “ZnO/ZnS(O,OH)/Cu(In,Ga)Se/Mo Solar Cell with
a0
18:6% Efficiency.”s from3d World Conf. on Photoyol. Energy Conv.,
Late News&8Paper, (2003) pp. 570-573.
Cui et al., “Harvest of near infrared light in PbSe nanocrystal-poly

2009,0263816 A1

10, 2009 Pickett et al.

2010.0059721 A1

3/2010 Pickett et al.

2010.0068522 A1
2010.0113813 A1

3/2010 Pickett et al.
5, 2010 Pickett et al.

2010, 0123155 A1

5, 2010 Pickett et al.

2010.0193767 A1

8/2010 Naasani et al.

2010/0212544 A1

EP
EP

GB
GB
JP
WO

8, 2010 Harris et al.

FOREIGN PATENT DOCUMENTS
1783 137
5/2007
1854,792
11, 2007
1995-18910.6
9, 1995
24298.38
3, 2007
2005,139389
6, 2005
WO-97/101.75

3, 1997

hybird photovoltaic cells. Appl. Physics Lett. 88 (2006) 18311
ity
photovoltaic cells.” Appl. Finysics Let.
y

&8

Cuberland et al., “Inorganic Clusters as Single-Source Precursors for
P

ion of CdSe, ZnS

ials'
reparation of CdSe, ZnSeand ColSe/ZnSN
efAnS Nanomaterials Chemi
ChemS

try of Materials, 14, pp. 1576-1584, (2002).
Dance et al., J. Am. Chem. Soc. (1984) 106:6285.
Daniels et al, New Zinc and Cadmium Chalcogenide Structured
Nanoparticles, Mat Res. Soc. Symp. Proc. 789 (2004).
s
Eychmüller, A. etal. "A quantum doiquantum well: CdS/HgS/CdS”.
Chem. Phys. Lett. 2008, pp. 59-62 (1993).
Fendler, J.H. et al. “The Colloid Chemical Approach to
Nanostructured Materials”. Adv. Mater. (1995) 7:607-632.

US 8,524.365 B2
Page 3
Gao, M. etal. “Synthesis of PbS Nanoparticles in Polymer Matrices'.
J. Chem. Soc. Commun. (1994) pp. 2779-2780.
Gou et al., J. Am. Chem. Soc. (2006) 128:7222-7229.
Gur et al., “Air Stable all-inorganic nanocrystal Solar cells processed
from solution.” Lawrence Berkeley Natl. Lab., Univ. of California,
paper LBNL-58424 (2005).
Gurin, Colloids Surf. A (1998) 142:35-40.
Guzelian, A. etal. "Colloidal chemical synthesis and characterization
of InAs nanocrystal quantum dots”, Appl. Phys. Lett. (1996) 69:

Nazeeruddin et al., “Engineering of Efficient Panchromatic Sensitiz
ers for Nanocrystalline TiO2-Based Solar Cells,” J. Am. Chem. Soc.
(2001) 123:1613-1624.

1432-1434.

Olson et al., J. Phys. Chem. C., (2007) 1 11:16640-16645.
Patents Act 1977: Search Report under Section 17 for Application
No. GB0409877.8 dated Oct. 7, 2004 (2 pages).
Patent Act 1977 Search Report under Section 17 for Application No.
GB0522027.2 dated Jan. 27, 2006 (1 page).
Patent Act 1977 Search Report under Section 17 for Application No.
GB0606845.6 dated Sep. 14, 2006.
Patent Act 1977 Search Report under Section 17 for Application No.

Guzelian, A. et al., J. Phys. Chem. (1996) 100: 7212.
Hagfeldt, A. et al. “Light-induced Redox Reactions in Nanocrystal
line Systems”, Chem. Rev. (1995):95: 49-68.
Henglein, A. "Small-Particle Research: Physicochemical Properties
of Extremely Small Colloidal Metal and Semiconductor Particles'.
Chem Rev. (1989) 89: 1861-1873.
Hirpo et al., “Synthesis of Mixed Copper-Indium Chalcogenolates.
Single-Source Precursors for the Photovoltaic Materials CuInO2
(Q=S. Se).” J. Am. Chem. Soc. (1993) 115:1597.
Hu et al., Sol. State Comm. (2002) 121:493-496.
International Search Report for PCT/GB2005/00 1611 mailed Sep. 8,
2005 (5 pages).
Jegier, J.A. et al. “Poly(imidogallane): Synthesis of a Crystalline 2-D
Network Solid and Its Pyrolysis To Form Nanocrystalline Gallium
Nitride in Supercritical Ammonia'. Chem. Mater. (1998) 10: 2041
2043.

Jiang et al., Inorg. Chem. (2000) 39:2964-2965.
Kaelin el al., “CIS and CIGS layers from selenized nanoparticle
precursors.” Thin Solid Films 431-432 (2003) pp. 58-62.
Kapur et al., “Non-Vacuum processing of Culin-GaSe Solar cells
on rigid and flexible Substrates using nanoparticl precursor inks.”
Thin Solid Films 431-432 (2003) pp. 53-57.
Kher, S. et al. “A Straightforward, New Method for the Synthesis of
Nanocrystalline GaAs and GaP, Chem. Mater. (1994)6: 2056-2062.
Kimetal. “Synthesis of CulnGaSe2 Nanoparticles by Low Tempera
ture Colloidal Route.” J. Mech. Sci. Tech., Vo. 19, No. 11, pp. 2085
2090 (2005).
Law et al., “Nanowire dye-sensitized solar cells.” Nature Mater.
(2005) vol. 4 pp. 455-459.
Li et al., Adv. Mat. (1999) 11:1456-1459.
Lieber, C. et al. “Understanding and Manipulating Inorganic Mate
rials with Scanning Probe Microscopes'. Angew. Chem. Int. Ed.
Engl. (1996) 35: 687-704.
Little et al., “Formation of Quantum-dot quanturn-well
heteronanostructures with large lattice mismatch: Zn/CdS/ZnS,” 114
J. Chem. Phys. 4 (2001).
Lu et al., Inorg. Chem. (2000) 39:1606-1607.
LOver, T. etal. "Preparation of a novel CodSnanocluster material from
a thiophenolate-capped CdS cluster by chemical removal of SPh
ligands”. J. Mater. Chem. (1997) 7(4): 647-651.
Malik et al., Adv. Mat., (1999) 11:1441-1444.
Matijevic, E., “Monodispersed Colloids: Art and Science”, Langmuir
(1986) 2:12-20.
Matijevic, E. "Production of Mondispersed Colloidal Particles'.
Ann. Rev. Mater. Sci. (1985) 15:483-5 18.
Mekis, I. et al., “One-Pot Synthesis of Highly Luminescent CdSet.
CdS Core-Shell Nanocrystals via Organometallic and "Greener”
Chemical Approaches”, J. Phys. Chem. B. (2003) 107: 7454-7462.
Mews et al., J. Phys. Chem. (1994) 98:934.
Micic et al., “Synthesis and Characterization of InP, GaP, and GainP.
Quantum Dots”, J. Phys. Chem. (1995) pp. 7754–7759.
Milliron et al., “Electroactive Surfactant Designed to Mediate Elec
tron Transfer between CdSe Nanocrystals and Organic Semicondic
tors.” Adv. Materials (2003) 15, No. 1, pp. 58-61.
Murray, C.B. et al., “Synthesis and Characterization of Nearly
Monodisperse CoE (E = S, Se, Te) Semiconductor Nanocrystallites”.
J. Am. Chem. Soc. (1993) 115 (19) pp. 8706-8715.
Nairn et al., Nano Letters (2006) 6:1218-1223.
Nazeeruddin et al., “Conversion of Light to Electricity by cis
X2Bis(2.2"bipyridyl-4,4'-dicarboxylate)ruthenium(II)
Charge
Transfer Sensitizers (X=C1-, Br-, I-, CN-, and SCN-) on
Nanocrystalline TiO, Electrodes.” J. Am. Chem. Soc. (1993)
115:6382-6390.

O'Brien et al., “The Growth of Indium Selenide Thin Films frorn a

Novel Asymmetric Dialkydiselenocarbamate.” 3 Chem. Vap. Depos.
4, pp. 227 (1979).
Olshavsky, M.A., et al. “Organometallic Synthesis of GaAs Crystal
lites Exhibiting Quantum Confinement”. J. Am. Chem. Soc. (1990)
1.12: 9438-9439.

GB0719073.9 dated Feb. 29, 2008.

Patent Act 1977 Search Report under Section 17 for Application No.
GB0719075.4 dated Jan. 22, 2008.

Patent Act 1977 Search Report under Section 17 for Application No.
GB0723539.3 dated Mar. 27, 2008 (1 page).
Peng et al., “Mechanisms of the Shape Evolution of CdSe
Nanocrystals”, J. AM. Chem. Soc. (2001) 123: 1389.
Peng et al., “Kinetics of I-VI and III-V Colloidal Semiconductor
Nanocrystal Growth: "Focusing” os Size Distributions”. J. Am.
Chem. Soc., (1998) 129: 5343-5344.
Penget al., “Shape control of CdSe nanocrystals', Nature, (2000) vol.
404, No. 6773, pp. 59-61.
Pradhan, N. et al. “Single-Precursor, One-Pot Versatile Synthesis
under near Ambient Conditions of Tunable. Single and Dual Band
Flourescing Metal Sulfide Nanoparticles'. J. Am. Chem. Soc. (2003)
125: 2050-2051.

Qi et al., “Efficient polymer-nanocrystal quantum-dot photodetec
tors.” Appl. Physics Lett. 86 (2005) 093103-093103-3.
Qu, L. et al. “Alternative Routes toward High Quality CdSe
Nanocrystals', Nano Lett. (2001) vol. 1, No. 6, pp. 333-337.
Robel et al., “Quantum Dot Sellar Cells. Harvesting Light Energy
with CdSe Nanocrystals Molecularly Linked to Mesoscopic TiO2
Films,” J. Am. Chem. Soc. (2006) 128; 2385-2393.
Salata, O.V. et al. “Uniform GaAs quantum dots in a polymer
matrix”, Appl. Phys. Letters (1994) 65(2): 189-191.
Sercel, P.C. et al. “Nanometer-scale GaAs clusters from

organometallic percursors”, Appl. Phys. Letters (1992)61: 696-698.
Shulz et al., J. Elect. Mat. (1998) 27:433-437.
Steigerwald, M.L. et al. “Semiconductor Crystallites: A Class of
Large Molecules”. Acc. Chem. Res. (1990) 23: 183-188.
Stroscio, J.A. et al. "Atomic and Molecular Manipulation with the
Scanning Tunneling Microscope'. Science (1991), 254: 1319-1326.
Trinidade et al., “A Single Source Spproach to the Synthesis of CdSe
Nanocrystallites”. Advanced Materials, (1996) vol. 8, No. 2, pp.
161-163.

Vayssieres et al., “Highly Ordered SnO, Nanorod Arrays from Con
trolled Aqueous Growth.” Angew. Chem. Int. Ed. (2004)43: 3666
3670.

Wang Y. et al. “PbS in polymers, From molecules to bulk solids'. J.
Chem. Phys. (1987) 87: 73.15-7322.
Weller, H. "Colloidal Semiconductor Q-Particles: Chemistry in the
Trasition Region Between Solid State and Molecules'. Angew.
Chem. int. Ed. Engl. (1993) 32: 41-53.
Weller, H. "Quantized Semiconductor Particles: A Novel State of
Mater for Materials Science”, Adv. Mater. (1993) 5: 88-95.
Wells, R.L. etal. “Synthesis of Nanocrystalline Indium Arsenide and
Indium Phosphide from Indium(III) Halides and Tris
(trimethyisilyl)pnicogens. Synthesis, Characterization, and Decom
position Behavior of I-In-P(SiMe),”, Chem. Mater. (1995)7: 793
800.

Xiao et al., J. Mater. Chem. (2001) 11:1417-1420.
Yang et al., Crystal Growth & Design (2007) 12:2562-2567.
Yu et al., “Polymer Photovoltaic Cells: Enhanced Efficiencies via a
Network of Internal Donor-Acceptor Heterojunctions,” 270 Science
5243 (1995), pp. 1789-1791.

US 8,524.365 B2
Page 4
Zhong et al., Nanotechnology 18 (2007) 025602.
Barron, “Group III Materials: New Phases and Nono-particles with
Applications in Electronics and Optoelectronics.” Office of Naval
Research Final Report (1999).
Dabousi et al., “(CdSe)ZnS Core—Shell Quantum Dots: Synthesis
and Characterization of a Size Series of Highly Luminescent
Nanocrystallites.” Jrl. Phys. Chem...(1997) 101, pp. 9463-9475.
Dehnen et al., “Chalcogen-Bridged Copper Clusters.” Eur, J. Inorg.
Chem. (2002) pp. 279-317.
Eisenmann et al., “New Phosphido-bridged Multinuclear Complexes
of Ag and Zn. Zeitschrift fur anorganische und allgemeine Chemi
(1995). (1 page—abstract).
Miller et al., “From Giant Molecular Clusters and Precursors to

Solid-state Structures.” Current Opinion in Solid State and Materials
Science, 4 (Apr. 1999) pp. 141-153.
Timoshkin, “Group 13 imido metallanes and their heavier analogs
RMYRIn (M=Al. Ga, In;Y=N, PAs, Sb.” Coordination Chemistry
Reviews (2005).
Vittal, “The chemistry of inorganic and organometallic compounds
with adameantane-like structures.” Polyhedron, vol. 15, No. 10, pp.
1585-1642 (1996).
Zhong et al., “Composition-Tunable ZnxCu1-xSe Nanocrytals with
High Luminescence and Stability”, Jrl Amer. Chem. Soc. (2003).
International Search Report for PCT/GB2006/003028 mailed Jan.
22, 2007 (5 pages).
Nielsch et al., “Uniform Nickel Deposition into Ordered Alumina
Pores by Pulsed Electrodeposition'. Advanced Materials, 2000 vol.
12, No. 8, pp. 582-586.
Huang et al., "Bio-Inspired Fabrication of Antireflection
Nanostructures by Replicating Fly Eyes', Nanotechnology (2008)

Cao, “Effect of Layer Thickness on the Luminescence Properties of
ZnS/CdS/ZnS quantum dot quantum well'. J. of Colloid and inter
face Science 284:516-520 (2005).
Harrison et al. “Wet Chemical Synthesis on Spectroscopic Study of
CdHgTe Nanocrystals with Strong Near-infrared Luminescence”
Mat. Sci and Eng.B69-70:355-360 (2000).
Sheng et al. "In-Situ Encapsulation of Quantum Dots into Polymer
Microsphers”. Langmuir 22(8):3782-3790 (2006).
W. Peter Wuelfing et al., “Supporting Information for Nanometer
Gold Clusters Protected by Surface Bound Monolayers of Thiolated
Poly (ethylene glycol) Polymer Electrolyte” Journal of the American
Chemical Society (XP002529160) (1998).
International Search Report for PCT/GB2009/000510 mailed Jul. 6,
2010 (16 pages).
International Search Peport for PCT/GB2008/00395.8 mailed Sep. 4,
2009 (4 pages).
Banger et al., “Ternary single-source precursors for polycrystaline
thin-film solar cells' Applied Organometallic Chemistry, 16:617
627, XP002525473 Scheme 1 Chemical Synthesis (2002).
D Qi. M. Fischbein, M Drindic, S. Selmic, “Efficient polymer
nanocrystal quantum-dot photodetectors'. Appl. Phys. Lett., 2004,
84, 4295.

Shen et al., “Photoacoustic and photoelectrochemical characteriza
tion of CdSe-sensitized TiO2 electrodes composed of nanotubes and
nanowires' Thin Solid Films, Elsevier-Sequoia S.A. Lausanne, CH
vol. 499, No. 1-2, Mar. 21, 2006, pp. 299-305, XP005272241 ISSN:
0040-6090.

Smestad GP, et al., “A technique to compare polythiophene Solid
state dye sensitized TiO2 solar cells to liquid junction devices' Solar
Energy Materials and Solar Cells, Elsevier Science Publishers,
Amsterdam, NL, vol. 76, No. 1, Feb. 15, 2003, pp. 85-105,

vol. 19.

XPOO440O821 ISSN: 0927-0248.

Materials Research Society Symposium Proceedings Quantum Dots,
Nanoparticles and Nanowires, 2004, ISSN: 0272-9172.
Xie et al., “Synthesis and Characterization of Highly Luminescent
CdSe-Core CdS/ZnO.5CdO.5S/ZnS Multishell Nanocrystals.” JACS
Articles published on web Apr. 29, 2005.
Kim et al., “Engineering InASXP1-X/InP/ZnSe III-V Alloyed Core
Shell Quantum Dots for the Near-Infrared.” JACS Articles published

Chen et al., “Electrochemically synthesized CdS nanoparticle-modi
fied TiO2 nanotube-array photoelectrodes: Preparation, characteriza
tion, and application to photoelectrochemical cells' Journal of Pho
tochemistry and Photobiology, a: Chemistry, Elsevier Sequoia
Lausanne, CH, vol. 177, No. 2-3, Jan. 25, 2006, pp. 177-184,

on web Jul. 8, 2005.

Rao et al. “The Chemistry of Nanomaterials: Synthesis, Properties
and Applications” (2004).
Trinidade et al., “Nanocrystalline Seminconductors: Synthesis, Prop
erties, and Perspectives”. Chemistry of Materials, (2001) vol. 13, No.
11, pp. 3843-3858.
International Search Report for PCT/GB2009/001928 mailed Dec. 8,
2009 (3 pages).
International Search Report for PCT/GB2009/002605 mailed Feb.
22, 2010 (3 pages).
Search Report for GB0813273.0 searched Dec. 8, 2008 (1 page).
Search Report for GB0814458.6 searched Dec. 5, 2008 (2 pages).
Search Report for GB0820101.4 searched Mar. 3, 2009 (1 page).
Search Report for GB0821122.9 searched Mar. 19, 2009 (2 pages).
Foneberoy et al., “Photoluminescence of tetrahedral quantum-dot
quantum wells' Physica E, 26:63-66 (2005).

XPOO5239590 ISSN: 1010-6030.

Wang, et al., “In situ polymerization of amphiphilic diacetylene for
hole transport in Solid state dye-sensitized Solar cells' Organic Elec
tronics, El Sevier, Amsterdam NL, vol. 7, No. 6, Nov. 18, 2006, pp.
546-550, XP005773063 ISSN: 1566-1199.

International Search Report and Written Opinion for PCT/GB2008/
001457 mailed Aug. 21, 2008 (14 pages).
Richardson et al., “Chemical Engineering: Chemical and Biochemi
cal Reactors and Process Control.” vol. 3. Third Edition pp. 3-5
(1994).
Hu et al., Solar Cells: From basics to advanced systems. McGraw
Hill Book Co. pp. 73-74 (1983).
Talapinet al. “Synthesis of Surface-Modified Colloidal Serniconduc
tor Nanocrystals and Study of Photoinduced Charge Separation and
Transport in Nanocrystal-Polymer Composites.” Physica E. vol. 14.
pp. 237-241 (2002).

* cited by examiner

U.S. Patent

Sep. 3, 2013

HN

Sheet 3 of 18

O

O

50S

US 8,524,365 B2

U.S. Patent

0C0

sz DO

Sep. 3, 2013

Sheet 4 of 18

US 8,524,365 B2

U.S. Patent

Sep. 3, 2013

Sheet 5 of 18

US 8,524,365 B2

U.S. Patent

Sep. 3, 2013

(EIWNOLTAV|)9

E=|ZNHWTNORJWX:H

O

S

CfO
c

CD
s

g

SO
RO
CS

S

US 8,524,365 B2

Sheet 6 of 18

U.S. Patent

Sep. 3, 2013

Sheet 7 of 18

US 8,524,365 B2

U.S. Patent

Sep. 3, 2013

X

$-

Sheet 8 of 18

US 8,524,365 B2

U.S. Patent

Sep. 3, 2013

Sheet 9 of 18

US 8,524,365 B2

U.S. Patent

Sep. 3, 2013

Sheet 10 of 18

US 8,524,365 B2

U.S. Patent

Sep. 3, 2013

US 8,524,365 B2

Sheet 12 of 18

(ne) ALISNLN

0/9 7 8

(H10uNET )WM

U.S. Patent

Sep. 3, 2013

Sheet 13 of 18

US 8,524,365 B2

CD O O O CD O O O d
O O O O CD O C
O
Cd Cd Cd Cd Cd Cd Cd Cd
co S Lb od co cird S. Ld
r
x
x
.
CN CN CN CN

:

Cd
Cd
N

i i :

:

:

Cd
O
CCd

s
3.
CO

Cd

CO

Cd

St.

Cd

(n'e) ALISNLN

S

U.S. Patent

Sep. 3, 2013

Sheet 14 of 18

US 8,524,365 B2

097
(n'e) ALISNLN

(H10uNETHA)WM

U.S. Patent

Sep. 3, 2013

Sheet 15 of 18

O

ne) ALISNLN

US 8,524,365 B2

0/9 7

(H10uNElT W)M

`5)|–|
|

U.S. Patent

Sep. 3, 2013

Sheet 16 of 18

US 8,524,365 B2

(H10uNET)WM

U.S. Patent

Sep. 3, 2013

Sheet 18 of 18

US 8,524,365 B2

s

|
o

O

CC

O

N.

O

WISNN

CN

O

US 8,524,365 B2
1.
PREPARATION OF NANOPARTICLE
MATERALS
CROSS REFERENCE TO RELATED
APPLICATIONS

This application is a continuation of U.S. patent applica
tion Ser. No. 12/854,611 filed Aug. 11, 2010, now U.S. Pat.
No. 8,062.703, which is a continuation of U.S. patent appli
cation Ser. No. 1 1/579,050, filed Oct. 27, 2006, now U.S. Pat.

No. 7,803,423, issued Sep. 28, 2010, which is a U.S. national
stage application of International (PCT) Patent Application
Serial No. PCT/GB2005/001611, filed Apr. 27, 2005, which
claims the benefit of GB Application No. 0409877.8, filed
Apr. 30, 2004. The entire disclosures of each of these appli
cations are hereby incorporated by reference as if set forth at
length herein in their entirety.

10

non-radiative electron-hole recombination. One method to

15

in the core from surface states that would otherwise act as

There has been substantial interest in the preparation and
characterization, because of their optical, electronic and
chemical properties, of compound semiconductors consisting

little lattice mismatch to that of the core material, so that the
interface between the two materials has as little lattice strain

of particles with dimensions in the order of 2-100 nm, often

25

miniaturization of both optical and electronic devices' that

now range from commercial applications as diverse as bio
logical labeling, Solar cells, catalysis, biological imaging,
light-emitting diodes amongst many new and emerging appli

30

35

using "wet" chemical procedures.' " Rather, from “top

40

45

50

Surface atoms to those in the interior increases. This leads to

the Surface properties playing an important role in the overall
properties of the material. The second factor is that, with
semiconductor nanoparticles, there is a change in the elec
tronic properties of the material with size, moreover, the band
gap gradually becoming larger because of quantum confine
ment effects as the size of the particles decreases. This effect
is a consequence of the confinement of an electron in a box
giving rise to discrete energy levels similar to those observed
in atoms and molecules, rather than a continuous band as in

the corresponding bulk semiconductor material. Thus, for a
semiconductor nanoparticle, because of the physical param
eters, the “electron and hole', produced by the absorption of
electromagnetic radiation, a photon, with energy greater than
the first excitonic transition, are closer together than in the
corresponding nacrocrystalline material, so that the Coulom
bic interaction cannot be neglected. This leads to a narrow

lattice as a result of high latticed strain. Another approach is
to prepare a core-multi shell structure where the “electron
hole' pair is completely confined to a single shell Such as the
quantum dot-quantum well structure. Here, the core is of a
wide bandgap material, followed by a thin shell of narrower
bandgap material, and capped with a further wide bandgap
layer, such as CdS/HgS/CdS grown using a substitution of Hg
for Cd on the surface of the core nanocrystal to depositjust 1

monolayer of HgS.''The resulting structures exhibited clear

tallinebulk form. Two fundamental factors, both related to the

size of the individual nanoparticle, are responsible for their
unique properties. The first is the large Surface to Volume
ratio; as a particle becomes smaller, the ratio of the number of

mismatch between CdSe and ZnS, is large enough that in a
core-shell structure only a few monolayers of ZnS can be
grown before a reduction of the quantum yield is observed,
indicative of the formation of defects due to breakdown in the

Although some earlier examples appear in the literature.''

down” techniques involving the milling of Solids to finer and
finer powders.
To-date the most studied and prepared of semiconductor
materials have been the chalcogenides II-VI materials namely
ZnS, ZnSe, CdS, CdSe, CdTe; most noticeably CdSe due to
its tuneability over the visible region of the spectrum. As
mentioned semiconductor nanoparticles are of academic and
commercial interest due to their differing and unique proper
ties from those of the same material, but in the macro crys

as possible. Excessive strain can further result in defects and
non-radiative electron-hole recombination resulting in low
quantum efficiencies.
However, the growth of more than a few mono layers of
shell material can have the reverse effect thus; the lattice

cations.

recently methods have been developed from reproducible
“bottom up' techniques, whereby particles are prepared
atom-by-atom, i.e. from molecules to clusters to particles

eliminate defects and daggling bonds is to grow a second
material, having a wider band-gap and Small lattice mismatch
with the core material, epitaxially on the surface of the core
particle, (e.g. another II-VI material) to produce a “core-shell
particle'. Core-shell particles separate any carriers confined
non-radiative recombination centers. One example is ZnS
grown on the surface of CdSe cores. The shell is generally a
material with a wider bandgap then the core material and with

BACKGROUND OF THE DISCLOSURE

referred to as quantum dots and/or nanocrystals. These stud
ies have occurred mainly due to their size-tunable electronic,
optical and chemical properties and the need for the further

2
bandwidth emission, which is dependent upon the particle
size and composition. Thus, quantum dots have higher kinetic
energy than the corresponding nacrocrystalline material and
consequently the first excitonic transition (band gap)
increases in energy with decreasing particle diameter.
Single core nanoparticles, which consist of a single semi
conductor material along with an outer organic passivating
layer, tend to have relatively low quantum efficiencies due to
electron-hole recombination occurring at defects and dag
gling bonds situated on the nanoparticle Surface which lead to

55

60

confinement of photoexcited carriers in the HgSlayer.
The coordination about the final inorganic Surface atoms in
any core, core-shell or core-multi shell nanoparticles is
incomplete, with highly reactive “daggling bonds' on the
Surface, which can lead to particle agglomeration. This prob
lem is overcome by passivating (capping) the "bare' surface
atoms with protecting organic groups. The capping or passi
Vating of particles not only prevents particle agglomeration
from occurring, it also protects the particle from its Surround
ing chemical environment, along with providing electronic
stabilization (passivation) to the particles in the case of core
material. The capping agent usually takes the form of a Lewis
base compound covalently bound to Surface metal atoms of
the outer most inorganic layer of the particle, but more
recently, so as to incorporate the particle into a composite, an
organic system or biological system can take the form of an
organic polymer forming a sheaf around the particle with
chemical functional groups for further chemical synthesis, or
an organic group bonded directly to the Surface of the particle
with chemical functional groups for further chemical synthe
S1S.

65

Many synthetic methods for the preparation of semicon
ductor nanoparticles have been reported, early routes applied
conventional colloidal aqueous chemistry, with more recent
methods involving the kinetically controlled precipitation of
nanocrystallites, using organometallic compounds.

US 8,524,365 B2
4
polar solvent (methanol or ethanol or sometimes acetone) to
produce a precipitate of the particles that can be isolated by
filtration or centrifugation.

3
Over the past six years the important issues have concerned
the synthesis of high quality semiconductor nanoparticles in
terms of uniform shape, size distribution and quantum effi
ciencies. This has led to a number of methods that can rou

Due to their increased covalent nature III-V and IV-VI

tinely produce semiconductor nanoparticles, with monodis
persity of <5% with quantum yields >50%. Most of these
methods are based on the original “nucleation and growth

highly crystalline semiconductor nanoparticles are more dif
ficult to prepare and much longer annealing time are usually

other precursors that the organometallic ones used. Murray et
al originally used organometallic Solutions of metal-alkyls
(RM) M=Cd, Zn, Te: R=Me, Et and tri-n-octylphosphine
sulfide/selenide (TOPS/Se) dissolved in tri-n-octylphosphine
(TOP). These precursor solutions are injected into hot tri-noctylphosphine oxide (TOPO) in the temperature range 120
400° C. depending on the material being produced. This
produces TOPO coated/capped semiconductor nanoparticles
of II-VI material. The size of the particles is controlled by the
temperature, concentration of precursor used and length of
time at which the synthesis is undertaken, with larger par
ticles being obtained at higher temperatures, higher precursor
concentrations and prolonged reaction times. This organome
tallic route has advantages over other synthetic methods,
including near monodispersity <5% and high particle cystal
linity. As mentioned, many variations of this method have
now appeared in the literature which routinely give high
quality core and core-shell nanoparticles with monodisper
sity of <5% and quantum yield >50% (for core-shell particles
of as-prepared solutions), with many methods displaying a

2. GaP2? GaAs,’ 23, 24, 25, 26, InP27. 28, 29 InAs

required. However, there are now many reports' II-VI and
IV-VI materials being prepared by a similar procedure GaN.

method described by Murray, Norris and Bawendi..' but use

high degree of size' and shape' control.

10

15

Solution upon injection Subsequently lowers the reaction tem
perature (the volume of solution added is about/3 of the total
Solution) and inhibits further nucleation maintaining a narrow
nanoparticle size distribution. Particle growth being a Surface
catalyzes process or via Ostwald ripening, depending on the

precursor's used, continues at the lower temperature and
25

30

precursors which are less exotic and less expensive but not
necessary more environmentally friendly. Some of these new

precursors include the oxides, CdO;' carbonates MCO,
35

other.' 'The use of the term “greener” precursors in semi

conductor particle synthesis has generally taken on the mean
ing of cheaper, readily available and easier to handle precur
Sor starting materials, than the originally used
organometallics which are volatile and air and moisture sen
sitive, and does not necessary mean that “greener precursors'
are any more environmentally friendly).
Single-source precursors have also proved useful in the
synthesis of semiconductor nanoparticle materials of II-VI.
as well as other compound semiconductor nanoparticles. Bis
(dialkyldithio-/diseleno-carbamato)cadmium(II)/zinc.(II)
compounds, M(ECNR) (M=Zn or Cd, E=S or Se and
R=alkyl), have used a similar one-pot synthetic procedure,
which involved dissolving the precursor in tri-n-octylphos
phine (TOP) followed by rapid injection into hot tri-n-oc
tylphosphine oxide/tri-n-octylphosphine (TOPO/TOP)

clusters which Subsequently grow into nanoparticles of

40

CdS.34

Strouse and co-workers used a similar synthetic

45

50

55

method by Murray et al" which involves the rapid injection

of the precursors into a hot solution of a Lewis base coordi
nating solvent (capping agent) which may also contain one of
the precursors. The addition of the cooler solution subse
quently lowers the reaction temperature and assist particle
growth but inhibits further nucleation. The temperature is
then maintained for a period of time, with the size of the
resulting particles depending on reaction time, temperature
and ratio of capping agent to precursor used. The resulting
solution is cooled followed by the addition of an excess of a

thus nucleation and growth are separated. This method works
well for small scale synthesis where one solution can be
added rapidly to another while keeping a homogenous tem
perature throughout the reaction. However, on larger prepara
tive scale whereby large Volumes of Solution are required to
be rapidly injected into one another a temperature differential
can occur within the reaction which can Subsequently lead to
a large particle size distribution.
Preparation from single-source molecular clusters,
Cooney and co-workers used the cluster S.Cdo (SPh)
MeNHL to produce nanoparticles of CdS via the oxidation
of surface-capping SPh ligands by iodine. This route fol
lowed the fragmentation of the majority of clusters into ions

which were consumed by the remaining S.Cdo (SPh).It

above 200° C.

For all the above methods rapid particle nucleation fol
lowed by slow particle growth is essential for a narrow par
ticle size distribution. All these synthetic methods are based
on the original organometallic “nucleation and growth

Fundamentally all these preparations rely on the principle
of particle nucleation followed by growth, moreover, to have
a monodisperse ensemble of nanoparticles there must be
proper separation of nanoparticles nucleation from nanopar
ticle growth. This is achieved by rapid injection of one or both
precursors into a hot coordinating solvent (containing the
other precursor if otherwise not present) which initiates par
ticles nucleation, however, the sudden addition of the cooler

Recently attention has focused on the use of “greener”

M-Cd, Zn; acetates M(CH-CO), M=Cd, Zn and acetylac
etanates CH-COCH=C(O)CH M=Cd, Zn; amongst

27 and for

PbS and PbSe..?

60

65

approach but employed thermolysis (lyothermal) rather than
a chemical agent to initiate particle growth. Moreover, the
single-source precursors IMoSea (SPh) X, X—Li' or
(CH)NH, M-Cd or Zn were thermolysised whereby frag
mentation of some clusters occurs followed by growth of
other from scavenging of the free M and Se ions or simply
from clusters aggregating to form larger clusters and then
Small nanoparticles which Subsequently continue to grow
into larger particles.
According to the present invention there is provided a
method of producing nanoparticles comprising effecting con
version of a nanoparticle precursor composition to the mate
rial of the nanoparticles, said precursor composition compris
ing a first precursor species containing a first ion to be
incorporated into the growing nanoparticles and a separate
second precursor species containing a second ion to be incor
porated into the growing nanoparticles, wherein said conver
sion is effected in the presence of a molecular cluster com
pound under conditions permitting seeding and growth of the
nanoparticles.
The present invention relates to a method of producing
nanoparticles of any desirable form and allows ready produc
tion of a monodisperse population of such particles which are
consequently of a high purity. It is envisaged that the inven
tion is suitable for producing nanoparticles of any particular
size, shape or chemical composition. A nanoparticle may

US 8,524,365 B2
5
have a size falling within the range 2-100 nm. A sub-class of
nanoparticles of particular interest is that relating to com
pound semiconductor particles, also known as quantum dots
or nanocrystals.
An important feature of the invention is that conversion of
the precursor composition (comprising separate first and sec
ond precursor species) to the nanoparticles is effected in the
presence of a molecular cluster compound (which will be
other than the first or second precursor species). Without
wishing to be bound by any particular theory, one possible
mechanism by which nanoparticle growth may take place is
that each identical molecule of the cluster compound acts as
a seed or nucleation point upon which nanoparticle growth
can be initiated. In this way, nanoparticle nucleation is not
necessary to initiate nanoparticle growth because Suitable
nucleation sites are already provided in the system by the
molecular clusters. The molecules of the cluster compound
act as a template to direct nanoparticle growth. Molecular
cluster is a term which is widely understood in the relevant
technical field but for the sake of clarity should be understood

6
cluster compound compared to the total number of moles of
the first and second precursor species lies in the range 0.0035
O.OO45:1.
5

10

15

herein to relate to clusters of 3 or more metal or non-metal

atoms and their associated ligands of Sufficiently well-de
fined chemical structure such that all molecules of the cluster

compound possess the same relative molecular mass. Thus

25

the molecular clusters are identical to one another in the same

way that one H2O molecule is identical to another H2O mol
ecule. The use of the molecular cluster compound provides a
population of nanoparticles that is essentially monodisperse.
By providing nucleation sites which are so much more well
defined than the nucleation sites employed in previous work
the nanoparticles formed using the method of the present
invention possess a significantly more well defined final
structure than those obtained using previous methods. A fur
ther significant advantage of the method of the present inven
tion is that it can be more easily scaled-up for use in industry
than current methods. Methods of producing suitable
molecular cluster compounds are known within the art,
examples of which can be found at the Cambridge Crystallo
graphic Data Centre (www.ccdc.ca.ac.uk).
The conversion of the precursor composition to nanopar

30

35

40

ticle is carried out under conditions to ensure that there is

either direct reaction and growth between the precursor com
position and cluster, or some clusters grow at the expense of
others, due to Ostwald ripening, until reaching a certain size
at which there is direct growth between the nanoparticle and
the precursor composition. Such conditions ensure that the
monodispersity of the cluster compound is maintained
throughout nanoparticle growth which, in turn, ensures that a
monodisperse population of nanoparticles is obtained.
Any suitable molar ratio of the molecular cluster com
pound to first and second nanoparticle precursors may be
used depending upon the structure, size and composition of
the nanoparticles being formed, as well as the nature and
concentration of the other reagents, such as the nanoparticle
precursor(s), capping agent, size-directing compound and
solvent. It has been found that particularly useful ratios of the
number of moles of cluster compound compared to the total
number of moles of the first and second precursor species
preferably lie in the range 0.0001-0.1 (no. moles of cluster
compound): 1 (total no. moles of first and second precursor
species), more preferably 0.001-0.1:1, yet more preferably
0.001-0.060:1. Further preferred ratios of the number of
moles of cluster compound compared to the total number of
moles of the first and second precursor species lie in the range
0.002-0.030:1, and more preferably 0.003-0.020:1. In par
ticular, it is preferred that the ratio of the number of moles of

45

50

55

60

65

It is envisaged that any suitable molar ratio of the first
precursor species compared to the second precursor species
may be used. For example, the molar ratio of the first precur
Sor species compared to the second precursor species may lie
in the range 100-1 (first precursor species): 1 (second precur
sor species), more preferably 50-1:1. Further preferred ranges
of the molar ratio of the first precursor species compared to
the second precursor species lie in the range 40-5:1, more
preferably 30-10:1. In certain applications it is preferred that
approximately equal molar amounts of the first and second
precursor species are used in the method of the invention. The
molar ratio of the first precursor species compared to the
second precursor species preferably lies in the range 0.1-1.2:
1, more preferably, 0.9-1.1:1, and most preferably 1:1. In
other applications, it may be appropriate to use approximately
twice the number of moles of one precursor species compared
to the other precursor species. Thus the molar ratio of the first
precursor species compared to the second precursor species
may lie in the range 0.4–0.6:1, more preferably the molar ratio
of the first precursor species compared to the second precur
sor species is 0.5:1. It is to be understood that the above
precursor molar ratios may be reversed such that they relate to
the molar ratio of the second precursor species compared to
the first precursor species. Accordingly, the molar ratio of the
second precursor species compared to the first precursor spe
cies may lie in the range 100-1 (second precursor species):1
(first precursor species), more preferably 50-1:1, 40-5:1, or
30-10:1. Furthermore, the molar ratio of the second precursor
species compared to the first precursor species may lie in the
range 0.1-1.2:1, 0.9-1.1:1, 0.4–0.6:1, or may be 0.5:1.
The method of the present invention concerns the conver
sion of a nanoparticle precursor composition to a desired
nanoparticle. Suitable precursor compositions comprise two
or more separate precursor species each of which contains at
least one ion to be included in the growing nanoparticle. The
total amount of precursor composition required to form the
final desired yield of nanoparticles can be added before nano
particle growth has begun, or alternatively, the precursor
composition can be added in stages throughout the reaction.
The conversion of the precursor composition to the mate
rial of the nanoparticles can be conducted in any Suitable
solvent. In the method of the present invention it is important
to ensure that when the cluster compound and precursor com
position are introduced into the solvent the temperature of the
Solvent is sufficiently high to ensure satisfactory dissolution
and mixing of the cluster compound and precursor composi
tion. Once the cluster compound and precursor composition
are sufficiently well dissolved in the solvent the temperature
of the solution thus formed is raised to a temperature, or range
of temperatures, which is/are sufficiently high to initiate
nanoparticle growth. The temperature of the solution can then
be maintained at this temperature or within this temperature
range for as long as required to form nanoparticles possessing
the desired properties.
A wide range of appropriate solvents are available. The
particular solvent used is usually at least partly dependent
upon the nature of the reacting species, i.e. precursor compo
sition and/or cluster compound, and/or the type of nanopar
ticles which are to be formed. Typical solvents include Lewis
base type coordinating solvents, such as a phosphine (e.g.
TOP), a phosphine oxide (e.g. TOPO) or an amine (e.g.
HDA), or non-coordinating organic solvents, e.g. alkanes and
alkenes. If a non-coordinating solvent is used then it will

US 8,524,365 B2
8
16 of the periodic table and also including ternary and qua
ternary materials and doped materials. Nanoparticle material
include but are not restricted to:—MgS, MgSe, MgTe, CaS,

7
usually be used in the presence of a further coordinating agent
to act as a capping agent for the following reason.
If the nanoparticles being formed are intended to function
as quantum dots it is important to ensure that any dangling
bonds on the Surface of the nanoparticles are capped to mini

CaSe, CaTe, SrS, SrSe, SrTe, BaS, BaSe, BaTe.

IIB-VIB (12-16) material consisting of a first element from
group 12 of the periodic table and a second element from
group 16 of the periodic table and also including ternary and
quaternary materials and doped materials. Nanoparticle

mize non-radiative electron-hole recombination and inhibit

particle agglomeration which can lower quantum efficien
cies. A number of different coordinating solvents are known
which can also act as capping or passivating agents, e.g.TOP,
TOPO or HDA. If a solvent is chosen which cannot act as a

10

capping agent then any desirable capping agent can be added
to the reaction mixture during nanoparticle growth. Such
capping agents are typically Lewis bases but a wide range of
other agents are available. Such as oleic acid and organic
polymers which form protective sheaths around the nanopar

15

ticles.

A further way to avoid problems related to non-radiative
electron-hole recombination is to grow one or more shells
around the nanoparticle core to form a “core-shell nanopar
ticle. Such shells are well known in the art and are typically
comprised of a different material to that of the core. The shell
material is usually selected so as to have a wider band gap

but is not restricted to:- BP, AlP, AlAs. AlSb; GaN, GaP.
GaAs, GaSb. InN, InP, InAs, InSb, AlN, BN.

than the core material but to have as little lattice mismatch

with the core as possible to minimize lattice strain at the
core-shell interface which could lower quantum efficiencies

25

due to non-radiative electron-hole recombination.

The progress of nanoparticle growth can be monitored in
any convenient way, such as photoluminescence (PL) or UV
visible (UV-vis) spectroscopy. Once nanoparticles have been
produced having the desired properties, e.g. when a nanopar
ticle peak is observed on the PL/UV-vis emission spectra at
the desired wavelength, further growth is inhibited by altering
the reaction conditions, e.g. reducing the temperature of the
Solution below that necessary to Support nanoparticle growth.
At this stage the nanoparticles can be isolated immediately
from Solution by any convenient means, such as precipitation,
or allowed to anneal at a Suitable temperature for any desir
able amount of time, e.g. 10 minutes to 72 hours, to size
focus via Ostwald ripening prior to isolation. Following ini
tial isolation, the nanoparticle material may then be subject to
one or more rounds of Washing to provide a final product of
high purity.
It is also envisaged that a shape directing compound. Such
as a phosphonic acid derivative, may be added to the reaction
mixture to encourage the growing nanoparticles to adopt a
particular shape, e.g. spheres, rods, disks, tetrapods or stars,
which may be of use in particular applications.
The invention comprises of a method to produce nanopar
ticle materials mainly but not restricted to compound semi
conductor nanoparticles from the use of molecular clusters,
whereby the clusters are defined identical molecular entities,
as compared to ensembles of Small nanoparticles, which
inherently lack the anonymous nature of molecular clusters.

30

35

40

45

50

Nanoparticle material consisting of a first element from
any group in the transition metal of the periodic table, and a
second element from any group of the d-block elements of the
periodic table and also including ternary and quaternary
materials and doped materials. Nanoparticle material include
but is not restricted to: NiS, CrS, CuInS.
By the term doped nanoparticle for the purposes of speci
fications and claims, refer to nanoparticles of the above and a
dopant comprised of one or more main group or rare earth
elements, this most often is a transition metal or rare earth

55

molecular sources "molecular feedstocks' are used to facili

tate particle growth. These molecular feedstocks are a com
bination of separate precursors each containing one or more
element/ion required within the as to be grown nanoparticles.
Type of System to be Made
The present invention is directed to the preparation of a
number of nanoparticles materials and includes compound
semiconductor particles otherwise referred to as quantum
dots or nanocrystals, within the size range 2-100 nm and
include core material comprising:—
IIA-VIB (2-16) material, consisting of a first element from
group 2 of the periodic table and a second element from group

III-IV material consisting of a first element from group 13
of the periodic table and a second element from group 16 of
the periodic table and also including ternary and quaternary
materials and doped materials. Nanoparticle material include
but is not restricted to:—BC, AlC, GaC.
III-VI material consisting of a first element from group 13
of the periodic table and a second element from group 16 of
the periodic table and also including ternary and quaternary
materials. Nanoparticle material include but is not restricted
to:-Al2S3, Al-Sea. Al-Tes. Ga2S3, Ga-Sea, GeTe; In 2S,
In Sea, Ga-Tes, InTes, InTe.
IV-VI material consisting of a first element from group 14
of the periodic table and a second element from group 16 of
the periodic table, and also including ternary and quaternary
materials and doped materials. Nanoparticle material include
but is not restricted to:-PbS, PbSe, PbTe, SbTe, SnS,
SnSe, SnTe.

The invention consists of the use of molecular clusters as

templates to seed the growth of nanoparticles, whereby other

material includes but are not restricted to:—ZnS, ZnSe, ZnTe,

CdS, CdSe, CdTe. HgS, HgSe, HgTe.
II-V material consisting of a first element from group 12 of
the periodic table and a second element from group 15 of the
periodic table and also including ternary and quaternary
materials and doped materials. Nanoparticle material include
but is not restricted to:—Zn-P, ZnAS, Cd-P, Cd. As
Cd.N., Zn-N.
III-V material consisting of a first element from group 13 of
the periodic table and a second element from group 15 of the
periodic table and also including ternary and quaternary
materials and doped materials. Nanoparticle material include

60

65

element, Such as but not limited to Zinc sulfide with manga
nese, such as ZnS nanoparticles doped with Mn".
Ternary Phase
By the term ternary phase nanoparticle for the purposes of
specifications and claims, refer to nanoparticles of the above
but a three component material. The three components are
usually compositions of elements from the as mentioned
groups Example being (Zn, CdS).L. nanocrystal (where L
is a capping agent).
Quaternary Phase
By the term quaternary phase nanoparticle for the purposes
of specifications and claims, refer to nanoparticles of the
above but a four-component material. The four components
are usually compositions of elements from the as mentioned

groups Example being (Zn, CdS, Sei),L, nanocrystal
(where L is a capping agent).

US 8,524,365 B2
9

10

Solvothermal

By the term Solvothermal for the purposes of specifica
tions and claims, refer to heating the reaction Solution so as to
initiate and Sustain particle growth and can also take the
meaning Solvothermal, thermolysis, thermolsolvol. Solution
pyrolysis, lyothermal.

5

Core-Shell and Core/Multi Shell Particles

The material used on any shell or Subsequent numbers of
shells grown onto the core particle in most cases will be of a
similarlattice type material to the core material i.e. have close
lattice match to the core material so that it can be epitaxially
grown on to the core, but is not necessarily restricted to
materials of this compatibility. The material used on any shell
or Subsequent numbers of shells grown on to the core present
in most cases will have a wider band-gap then the core mate
rial but is not necessarily restricted to materials of this com
patibility. The materials of any shell or subsequent numbers
of shells grown on to the core can include material comprising

10

15

of—

IIA-VIB (2-16) material, consisting of a first element from
group 2 of the periodic table and a second element from group
16 of the periodic table and also including ternary and qua
ternary materials and doped materials. Nanoparticle material
include but is not restricted to:—MgS, MgSe, MgTe, CaS,

25

CaSe, CaTe, SrS, SrSe, SrTe.

IIB-VIB (12-16) material consisting of a first element from
group 12 of the periodic table and a second element from
group 16 of the periodic table and also including ternary and
quaternary materials and doped materials. Nanoparticle

30

material include but is not restricted to:—ZnS, ZnSe, ZnTe,

CdS, CdSe, CdTe. HgS, HgSe, HgTe.
II-V material consisting of a first element from group 12 of
the periodic table and a second element from group 15 of the
periodic table and also including ternary and quaternary
materials and doped materials. Nanoparticle material include
but is not restricted to:—Zn-P, ZnAS, Cd-P, Cd. As
Cd.N., Zn-N.
III-V material consisting of a first element from group 13 of
the periodic table and a second element from group 15 of the
periodic table and also including ternary and quaternary
materials and doped materials. Nanoparticle material include

35

40

but is not restricted to:- BP, AlP, AlAs. AlSb; GaN, GaP.
GaAs, GaSb. InN, InP, InAs, InSb, AlN, BN.

III-IV material consisting of a first element from group 13
of the periodic table and a second element from group 16 of
the periodic table and also including ternary and quaternary
materials and doped materials. Nanoparticle material include
but is not restricted to:—BC, Al C. GaC.
III-VI material consisting of a first element from group 13
of the periodic table and a second element from group 16 of
the periodic table and also including ternary and quaternary
materials. Nanoparticle material include but is not restricted
to:-Al2S, Al-Se. Al-Tes, Ga-S, Ga-Se: In-S, InSes,
Ga-Tes, In-Tes.
IV-VI material consisting of a first element from group 14
of the periodic table and a second element from group 16 of
the periodic table and also including ternary and quaternary
materials and doped materials. Nanoparticle material include
but is not restricted to:-PbS, PbSe, PbTe, Sb, Tes, SnS,

45

50

55

60

SnSe, SnTe.

Nanoparticle material consisting of a first element from
any group in the transition metal of the periodic table, and a
second element from any group of the d-block elements of the
periodic table and also including ternary and quaternary
materials and doped materials. Nanoparticle material include
but is not restricted to:—NiS, CrS, CuInS.

65

Outer Most Particle Layer
Capping Agent
The outer most layer (capping agent) of organic material or
sheath material is to inhibit particles aggregation and to pro
tect the nanoparticle from the Surrounding chemical environ
ment and to provide a means of chemical linkage to other
inorganic, organic or biological material. The capping agent
can be the solvent that the nanoparticle preparation is under
taken in, and consists of a Lewis base compound whereby
there is a lone pair of electrons that are capable of donor type
coordination to the Surface of the nanoparticle and can
include mono- or multi-dentate ligands of the type but not
restricted to:- phosphines (trioctylphosphine, triphenol
phosphine, thutylphosphine), phosphine oxides (trio
ctylphosphine oxide), alkyl-amine (hexadecylamine, octy
lamine), ary-amines, pyridines, and thiophenes.
The outer most layer (capping agent) can consist of a
coordinated ligand that processes a functional group that can
be used as a chemical linkage to other inorganic, organic or
biological material Such as but not restricted to:—mercapto
functionalized amines or mercaptocarboxylic acids.
The outer most layer (capping agent) can consist of a
coordinated ligand that processes a functional group that is
polymerisable and can be used to form a polymer around the
particle, polymerisable ligands such as but not limited to
styrene functionalized amine, phosphine or phosphine oxide
ligand.
Nanoparticle Shape
The shape of the nanoparticle is not restricted to a sphere
and can consist of but not restricted to a rod, sphere, disk,
tetrapod or star. The control of the shape of the nanoparticle is
by the addition of a compound that will preferentially bind to
a specific lattice plane of the growing particle and Subse
quently inhibit or slow particle growth in a specific direction.
Example of compounds that can be added but is not restricted
to include: phosphonic acids (n-tetradecylphosphonic acid,
hexylphoshonic acid, 1-decanesulfonic acid, 12-hydroxy
dodecanoic acid, n-octadecylphosphonic acid).
Description of Preparative Procedure
The current invention should lead to pure, monodisperse,
nanocrystalline particles that are stabilized from particle
aggregation and the Surrounding chemical environment by an
organic layer, where M and E are two different elements in a

(ME),L, particles and L being the coordinating organic layer/
PO), nanoparticle constituting of a ZnScore surrounded by

capping agent, such as a II-VI semiconductor (ZnS),(TO

trioctylphosphine oxide ligands (TOPO).
The first step for preparing nanoparticles of a semiconduc
tor material is to use a molecular cluster as a template to seed
the growth of nanoparticles from other element source pre
cursors. This is achieved by mixing Small quantity of a cluster
which is to be used as the template with a high boiling solvent
which can also be the capping agent, being a Lewis base
coordination compound Such as but not restricted to a phos
phine, a phosphine oxide or an amine such as TOP TOPO or
HDA; or an inert Solvent such as a alkane (octadecence) with
the addition of a capping agent compound Such as oleic acid.
Further to this a source for M and a source for E (for a ME
particle) are added to the reaction mixture. The M and E
precursor are in the form of two separate precursors one
containing M and the other containing E.
Further to this other regents mayor may not be added to the
reactions which have the ability to control the shape of the
nanoparticles grown. These additives are in the form of a
compound that can preferentially bind to a specific face (lat
tice plane) of the growing nanoparticle and thus inhibit or
slow grow along that specific direction of the particle. Other

US 8,524,365 B2
11
element source precursors may or may not be added to the
reaction so as to produce ternary, quaternary or doped par

12
Examples, clusters to be used but not restricted to
include:—

IIB-VIB:—{(PPh.)Hg (SPh):

ticles.

Initially, the compounds of the reaction mixture are
allowed to mix on a molecular level at a low enough tempera
ture where no particle growth will occur. The reaction mixture
is then heated at a steady rate until particle growth is initiated
upon the Surfaces of the molecular cluster-templates. At an
appropriate temperature after the initiation of particle growth
further quantities of M and E precursors may be added to the
reaction mixture if needed so as to inhibit particles consum
ing one another by the process of Ostwald ripening. Further
precursor addition can be in the form of batch addition
whereby solid precursor or solutions containing precursor are
added over a period of time or by continuous dropwise addi
tion. Because of the complete separation of particle nucle
ation and growth, the current invention displays a high degree
of control in terms of particle size, which is controlled by the
temperature of the reaction and concentrations of precursors
present. Once the desired particle size is obtained, as estab
lished from UV and/or PL spectra of the reaction solution
either by an in situ optical probe or from aliquots of the
reaction solution, the temperature may or may not be reduced
by ca. 30–40° C. and the mixture left to “size-focus’ for a
period of time being from 10 minutes to 72 hours.
Further consecutive treatment of the as formed nanopar
ticles to form core-shell or core-multi shell particles may be
undertaken. Core-shell particle preparation is undertaken
either before or after nanoparticle isolation, whereby the
nanoparticles are isolated from the reaction and redissolved
in new (clean) capping agent as this results in a better quan
tum yield. A source for N and a source for Y precursor are

10

15

aryl group: {RZn}{PR'al R=I, PetPh, R—SiMe:
MCl(PPh2)(PPrs), M=Zn, Cd: Li(thf). (Ph.
P)Cd:Zn(PPh)CI(PRR), PRR'—PMe"Pr, PBus,

25

30

35

40

IV-VI S{SnR}. R=C(SiMe), Me, Ph; Se{SnR}

45

R—CFs, C.H. Mes, p-Tol, C(SiMe)
Material consisting of a first element from any group in the
transition metals of the periodic table and a second element
from any group of the d-block elements include but are not
restricted to:—CuSe(PR). R=EtPh, "Prs, Cy:

50

Cu,Tes(PPreMe),
NiaSe(PPh3);
Agso
(TePh) Teo (PEt3);
AgaoSes(Se'Bu) (PnPrs)sl:
Co. (LL-Se) (PPh3): Co(L-Se)(PPh3): IWSea
(dmpe). Br: RuBi(CO): FeaP(CO): FeN(CO)12

Cu sTec ("Bu)(PPh.Et),

CuoTea (Bu),(PEt3)s:

MSource

used can consist of—

Both elements required within the as to be grown nanopar
ticle either with or without other elements present plus
organic moieties;
One element required within the as to be grown nanopar
ticle either with or without other elements present plus
organic moieties;
Neither element required within the as to be grown nano
particle either with or without other elements present plus
organic moieties;
The requirement of a cluster used, is to initiate particle
growth either via consumption of other clusters or from reac
tion with the precursors present. Thus, the cluster can be used
as a template for particle growth.

NBull RGaNR'R=Ph, Me: R'=Ph, CFs, SiMe, Bu: Et
GaNEt RGaPR' R—Pr. CH Me: R=Bu: CH Me:
RNInRI R—Cl, Br, I, Me: R'='Bu, CF, CHF: RInPR'
R=Pr, C.H.Me, Et; R'—SiPh, C.H.Me, Si'Prs:
RInPR R=Et, R'—SiMe(CMe"Pr)
III-VI (TBu)GaSel. TBuGaS); RInSel, R="Bu,
CMeEt, Si(Bu), C((SiMe)); RInS, R=Bu, CMeEt:
RGaS, R=TBu, CMe, Et, CEt: SAIR R=C(SMe),
CEtMe: SAINMes: TeAlR4 R=Cp*, CEtMe: (C
(SiMe))GaS: tBuGaS6: RGaSela R=Bu, CMeEt,

CEt, C(SiMe), Cp*, Bu: CdIn S. (H2O)2(CoHs
N4)2.s:

The invention includes the use of molecular clusters,

whereby the clusters used are identical molecular entities as
compared to nanoparticles, which inherently lack the anony
mous nature of molecular clusters in an assembly. The clus
ters act as "embryo-type' templates for the growth of nano
particles whereby other molecular sources precursors
contribute ions to the growth process and thus clusters Sub
sequently grow into particles. The molecular clusters to be

PEtPh: Zn(PBu)Cl.
III-V EtGaNEt; MeCaN(4-CHF); (MeGaNiBu);
RAINR' R=Me, CHiPr', Ph; R'=Pr', CHiPr', C.H.Me:
(SiPr). ASAIH): PrNAIHL: RAINR, R-Me, Et, Cl,
CHPh, CHiPr', Ph; R=MeH, Br, C=CPh, Pr, (CH), Me,
(CH)2NMe, SiPh: CHGa NCHCH(CH): MeGa

ME/NY core shell material.

The process may be repeated with the appropriate element
precursors until the desired core-multi shell material is
formed. The nanoparticles size and size distribution in an
ensemble of particles is dependent by the growth time, tem
perature and concentrations of reactants in Solution, with
higher temperatures producing larger nanoparticles.
Type of Cluster Used for Seeding

PPh, Pr: CdE(EPh)PR), E, E'=Te, Se, S: CdSe
(SePh)Cl. M.Te
M–Cd, Hg: Ph.MsCdo
(PEt), M=Te, Se:
II-V: RCdNR, R-Cl, Br, I, PEt, C–CSMe:
R'=PEt, I: RCdNR's R-alkyl oraryl group and R'-alkyl or

added to the reaction mixture and can be either in the form of

two separate precursors one containing N and the other con
taining Y or as a single-source precursor that contains both N
and Y within a single molecule to form a core-shell particle of

(Ph4Ph)(SEt) (Br)

(HgBr): (Ph-P)Hg (SEt).Br. HgTeN(CHCH
Et)44
IIB-VIB:-EtNHCdSe (SPh):
RME'Bus
M=Zn, Cd, Hg: E-S, Se, Te: R=Me, Et, Ph: XLEM
(SR), E=S, Se, Te, M=Zn, Cd, Hg: X-MeNH", Li",
EtNH: CdS (SPh)|L: Hg, Sea (SePh)(PPh"Pr):
Hg2Sea (SePh); CdoSea (SePh)2(PPrs); CdSea
(SePh) (PPh); M.(SPh)"DX, M=Zn, Cd, Hg:
X-Me-N", Li": Zn(SEt)Eto: MeMEiPr M=Zn, Cd, Hg:
E=S, Se, Te: RCdSR's R'—O(CIO), R=

55

60

For a compound semiconductor nanoparticle consisting of
elements (ME),L, a source for element M is further added to
the reaction and can consist of any M-containing species that
has the ability to provide the growing particles with a source
of M ions. The precursor can consist of but are not restricted
to an organometallic compound, an inorganic salt, a coordi
nation compound or the element.
Examples for II-VI, III-V, III-VI or IV-V for the first ele
ment include but are not restricted to:—

Organometallic such as but not restricted to a MR where

M-MgR-alkyl or aryl group (MgTBu); MR where M-Zn,

Cd, Te: R-alkyl oraryl group (MeZn, EtZnMeCd, EtCd);
MR. Where M-Ga, In, Al, B: R-alkyl or aryl group AlR.
65

GaR, InR (R-Me, Et, Pr).

Coordination compound Such as a carbonate but not
restricted to a MCO M=Ca, Sr., Ba, magnesium carbonate

US 8,524,365 B2
13
hydroxide (MgCO). Mg(OH); M(CO), M=Zn, Cd;
MCO, M=Pb:acetate: M(CH-CO), M=Mg, Ca, Sr. Ba; Zn,
Cd. Hg; M(CH-CO). M=B, Al. Ga, In: a 3-diketonate or
derivative thereof. Such as acetylacetonate (2.4-pentanedion
ate)MCHCOCH=C(O)CH), M=Mg, Ca,Sr., Ba, Zn, Cd,
Hg. MICHCOCH=C(O)CH M=B, Al. Ga, In. Oxalate
SrCO, CaCO BaCO, SnCO. Hydroxide M(OH)
M-Mg, Ca, Sr., Ba, Zn, Cd, Hg, e.g. Cd(OH). Sterate
M(C7HCOO). M=Mg, Ca, Sr., Ba, Zn, Cd, Hg.
Inorganic salt such as but not restricted to a Oxides SrO.
ZnO, CdO. In O, Ga.O., SnO, PbO; Nitrates Mg(NO),
Ca(NO), Sr(NO), Ba(NO), Cd(NO), Zn(NO),
Hg(NO), Al(NO), InCNO), Ga(NO), Sn(NO),
Pb(NO), An element Mg, Ca,Sr., Ba, Zn, Cd, Hg, B, Al. Ga,
In, Sn, Pb.

14
FIGS. 4A & B) Formation of a Gallium sulfide quantum

dot using TBuGaS), as the molecular seed and gallium(II)

10

agent,

15

E Source

For a compound semiconductor nanoparticle consisting of
elements (ME),L, a source for element E is further added to
the reaction and can consist of any E-containing species that
has the ability to provide the growing particles with a source
of Eions. The precursor can consist ofbut are not restricted to
an organometallic compound, an inorganic salt, a coordina
tion compound or an elemental source. Examples for an II
VI, III-V, III-VI or IV-V semiconductor were the second

25

element include but are not restricted to:—

Organometallic such as but not restricted to a NR, PR,

AsR, SbR (R=Me, Et, Bu, Bu, Pr, Phetc.); NHR, PHR,
AsHR, SbHR (R-Me, Et, Bu, Bu, Pr, Phetc.); NHR,
PHR, AsFIR, SbH.R. (R=Me, Et, Bu, Bu, Pr, Phetc.);

30

MR (M=S, SeTe: R=Me, Et, Bu, Bu etc.); HMR (M=S,
SeTe: R=Me, Et, Bu, Bu, Pr, Phetc); thiourea S=C(NH);

35

PH, AsH; M(NMe), M=P. Sh, As; dimethyldrazine
(MeNNH); ethylazide (Et-NNN): hydrazine (HNNH);
MeSiN.
Se=C(NH).
Sn(CH), Sn(CH), Sn(CH)2(OOCH).
Coordination compound Such as but not restricted to a
carbonate, MCO M=P. bismuth subcarbonate (BiO)CO:
M(CO); acetate M(CHCO), M=S, Se, Te: M(CHCO),
M=Sn, Pb or M(CHCO). M=Sn, Pb: a B-diketonate or
derivative thereof. Such as acetylacetonate (2.4-pentanedion
ate) CHCOCH=C(O)CHM M=Bi; CHCOCH=C
(O) CHM M=S, Se, Te: CHCOCH=C(O)CHM
M=Sn, Pb: thiourea, selenourea (HNC(=Se)NH2.
Inorganic salt Such as but not restricted to Oxides P.O.
ASO, SbO, SbO, SbOs, BiO, SO, SeO, TeO.
SnO, PbO, PbO; Nitrates Bi(NO), Sn(NO), Pb(NO),

45

50

in which:

FIG. 1) is a diagram of a) core particle consisting of a CdSe
core and HDA as an organic capping agent, b) core-shell
particle consisting of a CdSe core a ZnS shell and HDA as an
organic capping agent, c) core-multi shell organic capped
particle consisting of a CdSe core a HgS shell followed by a
ZnS shell with a HDA capping agent;
FIG. 2) Molecular clusters used as seeding agents: a) Zno

(SEt).Eto; b) RGaSa; c) Bu'GaS)7; d) IRInSea; and e)
DXLIMoSe(SPh) X=cation, M=Zn, Cd, Te;
FIGS. 3A & B) Formation of a Cadmium selenide quan
tum dot using Mo Sea (SPh) X, X=Li" or (CH)NH",
EtNH' as the molecular seed and cadmium acetate and tri
n-octylphosphine selenide as the cadmium and selenium ele
ment-source precursors and with Hexadecylamine used as the
capping agent,

FIGS. 6 A & B) Formation of a zinc sulfide quantum dot
using Zn(SEt).Eto as the molecular seed and Zinc acetate
and tri-n-octylphosphine Sulfide as the Zinc and Sulfur ele
ment-source precursors and with Hexadecylamine used as the
capping agent;
FIG. 7) Evolution of the PL spectra of CdSe nanoparticles
as the nanoparticles become bigger during growth. Prepara
tion from Et NHLCdSe (SPh)/TOPSe/Cd(CHCO),
in HDA in accordance with Example 1:
FIG. 8) Evolution of the PL spectra of CdSe nanoparticles
as the nanoparticles become bigger during growth. Prepara
tion from EtsNHCdSe (SPh)/TOPSe/Cd(CHCO)
in HDA in accordance with Example 2:
FIG.9) Evolution of the PL spectra of CdSe nanoparticles
as the nanoparticles become bigger during growth. Prepara
tion from EtNHCdSe (SPh)/TOP/Se/CdO in HDA
in accordance with Example 3:
FIG.10) Evolution of the PL spectra of CdSe nanoparticles
as the nanoparticles become bigger during growth. Prepara
tion from Et NHLCdSe (SPh)/TOPSe/Cd(OH), in
HDA in accordance with Example 4;
FIG. 11) Evolution of the PL spectra of CdSe nanoparticles
as the nanoparticles become bigger during growth. Prepara
tion from EtNHCdSe (SPh)/TOPSe/MeCd in
HDA in accordance with Example 5:
FIG.12) Evolution of the PL spectra of CdSe nanoparticles
as the nanoparticles become bigger during growth. Prepara
tion

40

An element:–Sn, Ge, N, PAs, Sb, Bi, S, Se, Te, Sn, Pb.

The present invention is illustrated with reference to the
following non-limiting Examples and accompanying figures,

acetylacetonate and tri-n-octylphosphine Sulfide as the gal
lium and Sulfide element-source precursors and with Hexa
decylamine used as the capping agent;
FIGS. 5A & B) Formation of a indium selenide quantum
dot using as the molecular seed and Indium(II)acetylaceto
nate and tri-n-octylphosphine Sulfide as the Indium and
Selenide element-source precursors and with Hexadecy
lamine and tri-n-octylphosphine oxide used as the capping

55

60

65

from

EtNHLCdSe (SPh)/TOPSe/

(C.H.COO), Cd in HDA in accordance with Example 7:
FIG. 13) Evolution of the PL spectra of CdSe nanoparticles
as the nanoparticles become bigger during growth. Prepara
tion from EtNHCdSe (SPh)/TOPSe/CdCO, in
HDA in accordance with Example 8:
FIG.14) Evolution of the PL spectra of CdTe nanoparticles
as the nanoparticles become bigger during growth. Prepara
tion from EtsNHCdSe (SPh)/Te as a slurry in TOP/
CdCHCO) in HDA in accordance with Example 9.
EXAMPLES

All syntheses and manipulations were carried out under a
dry oxygen-free argon or nitrogen atmosphere using standard
Schlenk or glove box techniques. All solvents were distilled
from appropriate drying agents prior to use (Na/K-benzophe
none for THF, EtO, toluene, hexanes and pentane). HDA,
octylamine, TOP, Cd(CH-CO), selenium powder, CdC).
CdCO (Aldrich) were procured commercially and used
without further purification.
UV-vis absorption spectra were measured on a He Xios3
Thermospectronic. Photoluminescence (PL) spectra were
measured with a Fluorolog-3 (FL3-22) photo spectrometer at
the excitation wavelength 380 nm. Powder X-Ray diffraction
(PXRD) measurements were pre-formed on a Bruker AXS
D8 diffractometer using monochromated Cu—K radiation.
For all methods all capping agent solutions were dried and
degassed before use by heating the mixture to 120° C. under

US 8,524,365 B2
15
a dynamic vacuum for at least 1 hour. The reaction mixture
was then cooled to the desired temperature for that particular
reaction before any seeding agent or growth precursors were
added to the solution.

Cluster Preparation
Preparation of IHNEtCd(SPh)
To a stirred methanol (60 ml) solution of benzenethiol
(20.00 g, 182 mmol) and triethylamine (18.50 g., 182 mmol)
was added dropwise CdCNO)4H2O (21.00 g, 68.00 mmol)
that had previously been dissolved in methanol (60 mL). The
solution was then allowed to stir while warming until the
precipitate had completely dissolved to leave a clear Solution.
This was then place at 5° C. for 24 h in which time large
colourless crystals of HNEtCd (SPh) had formed.
FW=1745.85. Anal. Calcu for C.H.N.S.Cd C=49.53,

10

15

H=4.70, N=1.61, S=18.37, Cd=25.75%. Found C=49.73,
H=4.88, N=1.59, S=17.92%

Preparation of IHNEtCdo (SPh)
This was by a similar procedure to that described by Dance

et al. To a stirred acetonitrile (100 ml) solution of IHNEts),

Cd.(SPh) (80.00 g, 45.58 mmol) was added 3.57 g 45.2
mmol of selenium powder, the resulting slurry was left to stir
for 12 hours, this produced a white precipitate. A further 750

16
prepared from dissolving selenium powder in TOP and
Cd(CHCO), dissolved in TOP (0.5M, 4 ml, 2.00 mmol) the
temperature of reaction mixture was gradually increased
from 70° C. to 150° C. over an hour period. A further 17 ml
(17.00 mmol) of TOPSe and 27 ml of a 0.5M Cd(CHCO),
dissolved in TOP (13.50 mmol) were added dropwise while
the temperature was gradually increased to 200°C. over a 24
hour period. The progressive formation/growth of the nano
particles was monitored by their emission wavelength by
taking aliquots from the reaction mixture and measuring their
UV-vis and PL spectra. The reaction was stopped when the
emission spectra had reached the desired size 630 nm by
cooling the reaction to 60°C. followed by addition of 200 ml
of dry “warm' ethanol which gave a precipitation of particles.
The resulting CdSe were dried before re-dissolving intoluene
filtering through Celite followed by re-precipitation from
warm ethanol to remove any excess HDA. This produced 4.56
g of HDA capped CdSe nanoparticles.
Example 3
Preparation of CdSe Nanoparticles from Et NHL
CdSe (SPh)/TOP/Se/CdO in HDA

ml of acetonitrile was added and the solution warmed to 75°

C. to give a clear pale yellow solution which was allowed to
cool to 5°C., yielding large colourless crystals. The crystals
were washed in hexane and recrystallized from hot acetoni
trile. To give 22.50 g of HNEtCdSe (SPh).
FW-3595.19 Anal. Calc for CHNSeSCdo.
C=40.08, H=4.00, N=1.56, S=14.27, Se=8.78, Cd=31.26%.
Found C=40.04, H=4.03, N=1.48, S=14.22, Cd=31.20%.

25

30

Example 1
Preparation of CdSe Nanoparticles from Et NHL
CdSe (SPh)/TOPSe/Cd(CHCO) in HDA

35

HDA (300 g) was placed in a three-neck flask and dried/
degassed by heating to 120° C. under a dynamic vacuum for
1 hour. The solution was then cooled to 70° C. To this was

added 1.0 g of Et NHCdSe (SPh) (0.311 mmol),
TOPSe (20 ml. 40.00 mmol) previously prepared from dis
solving selenium powder in TOP and CdCCHCO) (10.66g
40.00 mmol) the temperature of reaction mixture was gradu
ally increased from 70° C. to 180° C. over an 8 hour period.
The progressive formation/growth of the nanoparticles was
monitored by their emission wavelength by taking aliquots
from the reaction mixture and measuring their UV-vis and PL
spectra. The reaction was stopped when the emission spectra
had reached 572 nm by cooling the reaction to 60° C. fol
lowed by addition of 200 ml of dry “warm' ethanol which
gave a precipitation of nanoparticles. The resulting CdSe
were dried before re-dissolving in toluene filtering through
Celite followed by re-precipitation from warm ethanol to
remove any excess HDA and CdCHCO). This produced
9.26 g of HDA capped CdSe nanoparticles.
Example 2
Preparation of CdSe Nanoparticles from Et NHL
CdSe (SPh)/TOPSe/Cd(CHCO), in HDA
HDA (250 g) and octylamine (20g) was placed in a three
neck flask and dried/degassed by heating to 120° C. under a
dynamic vacuum for 1 hour. The solution was then cooled to
70° C. To this was added 1.0 g of EtNHCdSe (SPh)
(0.311 mmol), TOPSe (1M, 4 ml, 4.00 mmol) previously

40

HDA (150 g) and t-decylphosphonic acid (0.75 g) was
placed in a three-neck flaskand dried and degassed by heating
to 120° C. under a dynamic vacuum for 1 hour. The solution
was then cooled to 80°C. To this was added 0.5g of EtNHL
CdSe (SPh) (0.156 mmol), 20 ml of TOP 0.6 g of
selenium powder (7.599 mmol) and 0.8 g. CdC (6.23 mmol)
the reaction mixture was allowed to stir to give a pale red
cloudy mixture. The temperature of the reaction mixture was
gradually increased from 80°C. to 250° C. overa period of 24
h. The progressive formation/growth of the nanoparticles was
followed by their emission wavelength by taking aliquots
from the reaction mixture and measuring their UV-vis and PL
spectra. The reaction was stopped when the emission spectra
had reached the desired size (593 nm) by cooling the reaction
to 60° C. followed by addition of 200 ml of dry “warm”
ethanol, which gave a precipitation of particles. The resulting
CdSe were dried before re-dissolving in toluene filtering
through Celite followed by re-precipitation from warm etha
nol to remove any excess HDA. This produced 1.55g of HDA
capped CdSe nanoparticles.

45

Example 4
Preparation of CdSe Nanoparticles from Et NHL
CdSe (SPh)/TOPSe/Cd(HO), in HDA
50

HDA (400 g) was placed in a three-neck flaskand dried and
degassed by heating to 120° C. under a dynamic vacuum for
1 hour. The solution was then cooled to 70° C. To this was
55

60

65

added 1.00 g of EtNHCdSe (SPh) (0.278 mmol),
20.0 ml of TOPSe, (2M solution) and 5.85 g of Cd(OH)
(40.00 mmol), the reaction mixture was allowed to stir to give
a pale yellow cloudy mixture. The temperature of the reaction
mixture was gradually increased from 70° C. to 240° C. over
a period of 24 h. The progressive formation/growth of the
nanoparticles was followed by their emission wavelength by
taking aliquots from the reaction mixture and measuring their
UV-vis and PL spectra. The reaction was stopped when the
emission spectra had reached the desired size (609 nm) by
cooling the reaction to 60°C. followed by addition of 200 ml
of dry “warm' ethanol, which gave a precipitation of par
ticles. The resulting CdSe were dried before re-dissolving in
toluene filtering through Celite followed by re-precipitation

US 8,524,365 B2
17
from warm ethanol to remove any excess HDA. This pro
duced 10.18 g of HDA capped CdSe nanoparticles.
Example 5
Preparation of CdSe Nanoparticles from
Et3NH|4|Cd10Se4(SPh)16/TOPSe/Me2Cd in
HDA

HDA (100g) was placed in a three-neck flaskand dried and
degassed by heating to 120° C. under a dynamic vacuum for

10

1 hour. The solution was then cooled to 70° c. To this was

added 0.13 g of EtNHCdSe (SPh) (0.036 mmol),
2.5 ml of TOPSe, (2M solution) and 0.71 g MeCd that had
previously been dissolved in TOP (0.358 ml, 5.00 mmol) the
reaction mixture was allowed to stir. The temperature of the
reaction mixture was gradually increased from 80°C. to 260°
C. over a period of 24 h. The progressive formation/growth of
the nanoparticles was followed by their emission wavelength
by taking aliquots from the reaction mixture and measuring
their UV-Vis and PL spectra. The reaction was stopped when
the emission spectra had reached the desired size (587 nm) by
cooling the reaction to 60°C. followed by addition of 100 ml
of dry “warm' ethanol, which gave a precipitation of par
ticles. The resulting CdSe were dried before re-dissolving in
toluene filtering through Celite followed by re-precipitation
from warm ethanol to remove any excess HDA. This pro
duced 1.52 g of HDA capped CdSe nanoparticles.
Example 6

Example 8
15

Preparation of CdSe Nanoparticles from Et NHL
CdSe (SPh)/TOPSe/CdCO, in HDA
HDA (50 g) was placed in a three-neck flask and dried/
degassed by heating to 120° C. under a dynamic vacuum for
1 hour. The solution was then cooled to 75° C. To this was
25

30

Preparation of CdSe Nanoparticles from Et NHL
CdSe (SPh)/TOPSe/MeCd in HDA
HDA (100g) was placed in a three-neck flaskand dried and
degassed by heating to 120° C. under a dynamic vacuum for

35

1 hour. The solution was then cooled to 70° C. To this was

added 0.13 g of EtNHCdSe (SPh) (0.036 mmol).
The temperature was then increased to 100° C. and main
tained at this temperature while 2.5 ml of TOPSe, (2M solu
tion) and 0.71 gMeCd that had previously been dissolved in
TOP (0.358 ml, 5.00 mmol) were added dropwise over a 4
hour period. The progressive formation/growth of the nano
particles was followed by their emission wavelength by tak
ing aliquots from the reaction mixture and measuring their
UV-Vis and PL spectra. The reaction was stopped when the
emission spectra had reached the desired size (500 nm) by
cooling the reaction to 60°C. followed by addition of 100 ml
of dry “warm' ethanol, which gave a precipitation of par
ticles. The resulting CdSe were dried before re-dissolving in
toluene filtering through Celite followed by re-precipitation
from warm ethanol to remove any excess HDA. This pro
duced 1.26 g of HDA capped CdSe nanoparticles.
Example 7

40

45

Preparation of CdTe Nanoparticles from Et NH
CdSe (SPh)/TOPTe/Cd(ChCO) in HDA
50

HDA (200 g) was placed in a three-neck flask and dried/
degassed by heating to 120° C. under a dynamic vacuum for
1 hour. The solution was then cooled to 70° C. To this was

Preparation of CdSe Nanoparticles from Et NHL
CdSe (SPh)/TOPSe/(CHCOO)Cd in HDA
60

1 hour. The solution was then cooled to 80° C. To this was

added 0.5g of Et NHCdSe (SPh) (0.139 mmol). 20
ml of TOPSe (2M solution) and a solution of 2.568 gCdO (20
mmol) previously dissolved insteric acid (23.00 g), the reac
tion mixture was allowed to stir to give a pale yellow clear
Solution. The temperature of the reaction mixture was gradu
ally increased from 70° C. to 220° C. over a period of 24 h.

added 0.5 g of EtNHCdSe (SPh) (0.156 mmol),
TOPSe (1.0M, 5 ml, 5.00 mmol) previously prepared from
dissolving selenium powder in TOP and CdCO dissolved in
TOP (0.5M, 5 ml, 2.50 mmol) the temperature of reaction
mixture was gradually increased from 70° C. to 200° C. over
a 48 h period. The progressive formation/growth of the nano
particles were monitored by their emission wavelength by
taking aliquots from the reaction mixture and measuring their
UV-vis and PL spectra. The reaction was stopped when the
emission spectra had reached the desired size (587 nm) by
cooling the reaction to 60°C. followed by addition of 200 ml
of dry “warm' ethanol which gave a precipitation of particles.
The resulting CdSe were dried before re-dissolving intoluene
filtering through Celite followed by reprecipitation from
warm ethanol to remove any excess HDA. This produced 0.95
g of HDA capped CdSe nanoparticles.
Example 9

55

HDA (200g) was placed in a three-neck flaskand dried and
degassed by heating to 120° C. under a dynamic vacuum for

18
The progressive formation/growth of the nanoparticles was
followed by their emission wavelength by taking aliquots
from the reaction mixture and measuring their UV-vis and PL
spectra. The reaction was stopped when the emission spectra
had reached the desired size (590 nm) by cooling the reaction
to 60° C. followed by addition of 400 ml of dry “warm”
ethanol, which gave a precipitation of particles. The resulting
CdSe were dried before re-dissolving in toluene filtering
through Celite followed by re-precipitation from warm etha
nol to remove any excess HDA. This produced 4.27g of HDA
capped CdSe nanoparticles.

65

added 1.0 g of EtNHCdSe (SPh) (0.311 mmol), a
brown slurry of TOP (20 ml) with tellurium (2.55g, 20.00
mmol) along with Cd(CHCO) (4.33 g, 20.00 mmol) was
added. The temperature of reaction mixture was gradually
increased from 70° C. to 160° C. over an 8 hour period. The
progressive formation/growth on the CdTe nanoparticles was
monitored by their emission wavelengths by taking aliquots
from the reaction mixture and measuring their UV-vis and PL
spectra. The reaction was stopped when the emission spectra
had reached (624 nm) by cooling the reaction to 60° C.
followed by addition of 200 ml of dry “warm' ethanol which
gave a precipitation of particles. The resulting CdTe were

US 8,524,365 B2
19
dried before recrystallizing from toluene followed by re-pre
cipitation from warm ethanol to remove any excess
HDA.This produced 6.92 g of HDA capped CdTe nanopar

20
34. LOver, T.; Bowmaker, G. A.; Seakins, J. M.; Cooney, RP;
Henderson, W.J. Mater. Chem., 1997, 7(4),647.
35. Cumberland, S. L.; Hanif, K. M.; Javier, A.; Khitov, K.A.:
Strouse, G. F.; Woessner, S. M.; Yun, C. S. Chem. Mater.
2002, 14, 1576.

ticles.

36. Dance, I. G.; Choy, A.; Scudder, M. L. J. Am. Chem. Soc.,

REFERENCES

1984, 106, 6285.

1. Henglein, A. Chern. Rev. 1989, 89, 1861.
2. Steigerwald, M. L.; Brus, L. E. Acc. Chem. Res. 1990, 23,
183.

The invention claimed is:
10

3. Bawendi, M. G.; Steigerwald, M. L.; Brus, L. E. Annu. Rev.
Phys. Chem., 1990, 41, 477.
4. Weller, H. Angew. Chem. Int. Ed. Engl. 1993, 32, 41.
5. Weller, H. Adv. Mater, 1993, 5, 88.

6. Hagfeldt, A.; Grätzel, M. Chem. Rev. 1995, 95, 49.

15

7. Fendler, J. H.; Meldrum, F. C. Adv. Mater: 1995, 7, 607.

8. Alivisatos, A. P.; J. Phys. Chem. 1996, 100, 13226.
9. Stroscio, J. A.; Eigler, D. M. Science 1991, 254, 1319.
10. Lieber, C. M.; Liu, J.; Sheehan, P. Angew. Chem. Int. Ed
Engl. 1996, 35, 687.
11. Berry, C. R. Phys. Rev. 1967, 161,848.
12. Matijevic, E. Ann. Rev. Mater. Sci. 1985, 15, 483.
13. Matijevic, E. Langmuir 1986, 2, 12.
14. A Eychmüller, A. Mews, and H. Weller, Chern. Phys. Lett.
208, p. 59 (1993).
15. Murray, C.B.; Norris, D.J.; Bawendi, M. G.J. Am. Chem.

15, and 16 elements.

25

Soc. 1993, 115,8706.

16. A. P. Alivisatos, J. Wickham, X. G. Peng, J. Am. Chem.
Soc, 1998, 120, 5343.

30

17. X. G. Peng, L. Manna, W. D. Yang, J. Wickham, E. Scher,
A. Kadavanich, A. P. Alivisatos, Nature 2000, 404, 59.
18. Peng, Z. A.; Peng, X. G. J. Am. Chem. Soc. 2001, 123,
1389.

19.a) Bunge, S. D.; Krueger, K. M.; Boyle, T. J.; Rodriguez,
M.A.: Headley, T. J.; Colvin, V. L., J. Mater. Chem., 2003,
13, 1705:b) Aldana, J.; Wang, Y.A.; Peng, X.1. Am. Chem.
Soc. 2001, 123,8844.
20. Pradhan N.; Efrima S.J. Am. ChemSoc. 2003, 125, 2050;
Qu, L.; Peng, Z. A.; Peng, X. Nano Lett. 2001, 1,333.

35

10. The nanoparticle of claim 1, further comprising a shell
40

45

24. Sercel, P. C.; Saunders, W.A., Atwater, H. A.; Vahala, K.

J.; Flagan, R.C. Appl. Phys. Lett., 1992, 61, 696.
25. Olshaysky, M.A.: Goldstein, A.N.: Alivisatos, A.P.J. Am.

50

Arnold, C.C.; Heath, J. R.J. Phys. Chem., 1996, 100,7212.
27. Wells, R L. Aubuchon, S. R; Kher, S. S.; Lube, M. S.;
White, P. Chem. Mater, 1995, 7,793.

28. Agger, J. R. Anderson, M. W.; Pemble, M. E.; Terasaki,
O.; Nozue, Y. J. Phys. Chem. B 1998, 102,3345.
29. Micic, O.I.; Sprague, J. R.: Curtis, C.J.; Jones, K. M.:
Machol, J. L.; Nozic, A.; Giessen, J. H.; Fluegel, B. Mohs,
G.; Peyghambarian, N.J. Phys. Chem., 1995, 99,7754.
30. Guzelian, A. A.; Banin, U.: Kadavanich, A.V.; Peng, X.:
Alivisatos, A. P. Appl. Phys. Lett., 1996, 69, 1432.
31. Wang, Y.; Suna, Mahler, A. W.; Kasowski, R. J. Chem.
Phys., 1987, 87, 73.15.
32. Gao, M.; Yang, Y.; Yang, B.: Bian, F.; Shen, J. J. Chem.
Soc. Commun., 1994, 2779.

33. Mekis, I.; Talapin, D. V.: Kornowski, A.; Haase, M.:
Weller, H. J. Phys. Chem. B., 2003, 107,7454.

element.

9. The nanoparticle of claim 8, wherein the core semicon

Mater, 1998, 10, 2041.
22. Kher, S. S.; Wells, R. L. Chern. Mater, 1994, 6, 2056.
23. Salata, O. V. Dobson, P. J.; Hull, P. J.; Hutchison, J. L.

Chem. Soc., 1990, 112,9438.
26. Guzelian, A. A.; Katari, J.E.B.: Kadavanich, A.V., Banin,
U.; Hamad, K., Juban, E.; Alivisatos, A. P.; Wolters, R. H.;

3. The nanoparticle of claim 1, wherein the molecular
cluster compound comprises one or more group 12 elements
and one or more group 16 elements.
4. The nanoparticle of claim 1, wherein the molecular
cluster compound is selected from the group of molecular
compounds consisting of 12-16, 12-15, 13-15, 13-16, and
14-16 molecular compounds.
5. The nanoparticle of claim 1, wherein the molecular
cluster compound comprises a group 12 element.
6. The nanoparticle of claim 5, wherein the core semicon
ductor material does not comprise a group 12 element.
7. The nanoparticle of claim 1, wherein the core semicon
ductor material is selected from the group of semiconductor
materials consisting of 2-16, 12-16, 12-15, 13-15, 13-14,
13-16, and 14-16 semiconductor materials.
8. The nanoparticle of claim 1, wherein the core semicon
ductor material comprises a group 13 element and a group 15
ductor material is InP or InAs.

21. Jegier, J. A.; McKernan, S.; Gladfelter, W. L. Chem.
Appl. Phys. Letters 1994, 65, 189.

1. A nanoparticle comprising a molecular cluster com
pound and a core semiconductor material disposed on the
molecular cluster compound, wherein the semiconductor
material comprises one or more elements not comprised
within the molecular cluster compound.
2. The nanoparticle of claim 1, wherein the molecular
cluster compound comprises one or more elements selected
from the group of elements consisting of group 2, 12, 13, 14.

55

60

semiconductor material on the core semiconductor material
wherein the shell semiconductor material and the core semi
conductor material are different.

11. The nanoparticle of claim 10, wherein the shell semi
conductor material comprises a group 12 element.
12. The nanoparticle of claim 11, wherein the shell semi
conductor material comprises zinc.
13. The nanoparticle of claim 10, wherein the shell semi
conductor material is a ternary semiconductor material.
14. The nanoparticle of claim 10, wherein the shell semi
conductor material is a quaternary semiconductor material.
15. The nanoparticle of claim 1, wherein the core semicon
ductor material is a ternary semiconductor material.
16. The nanoparticle of claim 1, wherein the core semicon
ductor material is a quaternary semiconductor material.
17. A nanoparticle according to claim 1, wherein the nano
particle is prepared by a process comprising:
effecting conversion of a nanoparticle precursor composi
tion to the core semiconductor material, the precursor
composition comprising a first precursor species con
taining a first ion to be incorporated into the core semi
conductor material and a separate second precursor spe
cies containing a second ion to be incorporated into the
core semiconductor material, and

65

wherein the conversion is effected in the presence of the
molecular cluster compound that is different from the
first precursor species and the second precursor species
and wherein the conversion is effected under conditions

permitting seeding and growth of the nanoparticles.

US 8,524,365 B2
21
18. The nanoparticle of claim 17, wherein the molecular
cluster compound comprises one or more elements selected
from the group of elements consisting of group 2, 12, 13, 14.
15, and 16 elements.

19. The nanoparticle of claim 17, wherein the molecular 5
cluster compound comprises one or more group 12 elements
and one or more group 16 elements.
20. The nanoparticle of claim 17, wherein the molecular
cluster compound comprises a group 12 element.
21. The nanoparticle of claim 20, wherein neither the first 10
precursor species nor the second precursor species comprises
a group 12 element.
22. The nanoparticle of claim 17, wherein one of the pre
cursor species comprises a group 13 element and the other of
the precursor species comprises a group 15 element.
15
23. The nanoparticle of claim 17, wherein one of the pre
cursor species comprises. In and the other of the precursor
species comprises P or AS.
k

k

k

k

k