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 2

USOO78O3423B2

(12) United States Patent

(10) Patent No.:
US 7.803,423 B2
(45) Date of Patent:
Sep. 28, 2010

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

(56)

References Cited

MATERLALS

U.S. PATENT DOCUMENTS

(75) Inventors: Paul O'Brien, High Peak (GB); Nigel

3,524,771
4,609.689
6,114,038
6,207,229
6,221,602
6,261,779
6,322.901

Pickett, East Croydon (GB)
(73) Assignee: Nanoco Technologies Limited,
Manchester (GB)
(*) Notice:

Subject to any disclaimer, the term of this
patent is extended or adjusted under 35
U.S.C. 154(b) by 1003 days.

A
A
A
B1
B1
B1
B1

8, 1970
9, 1986
9, 2000
3/2001
4/2001
7/2001
11/2001

Green
Schwartz et al.
Castro et al.
Bawendi et al.
Barbera-Guillem et al.
Barbera-Guillem et al.
Bawendi et al.

(Continued)
FOREIGN PATENT DOCUMENTS

(21) Appl. No.:

11/579,050

(22) PCT Fled:

Apr. 27, 2005

(86). PCT No.:

PCT/GB2OOS/OO1611

CN

1394599

2, 2003

(Continued)
OTHER PUBLICATIONS

S371 (c)(1),
(2), (4) Date:
(87)

Oct. 27, 2006

PCT Pub. No.: WO2OOS/106082

PCT Pub. Date: Nov. 10, 2005
(65)

Prior Publication Data

US 2007/O2O2333 A1

Aug. 30, 2007

Foreign Application Priority Data
(30)
Apr. 30, 2004 (GB) ................................. O4O9877.8

(51) Int. Cl.
B82B 3/00
COIB 700

(2006.01)
(2006.01)

C30B 700
(2006.01)
C30B 7/4
(2006.01)
(52) U.S. Cl. ............... 427/213.34; 427/212; 427/213.3:

427/213.31; 427/214; 427/215; 428/402;

(58)

428/403
Field of Classification Search .................. 427/212

See application file for complete search history.

Cumberland et al., “Inorganic Clusters as Single-Source Precursors
for Preparation of CdSe, ZnSe, and CdSe/ZnS Nanomaterials”,
Chemistry of Materials, (2002).*

(Continued)
Primary Examiner Michael Cleveland
Assistant Examiner—Lisha Jiang
(74) Attorney, Agent, or Firm Goodwin Procter LLP
(57)

ABSTRACT

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.
25 Claims, 14 Drawing Sheets
(c)

Diagram of a) core particle, b) core-shell particle, c) core-multishell organic capped particle

US 7,803.423 B2
Page 2
U.S. PATENT DOCUMENTS

6,326,144 B1
6,333,110 B1
6,379,635 B2

6,423,551
6.426,513
6,607,829
6,660,379
6,699,723
6,815,064
6,855,551
6,914,264
7,041,362
7,151,047
7,235,361
7,264,527

WO-2009016354 A1
WO-2009 10681.0 A1

12/2001 Bawendi et al.
12/2001 Barbera-Guillem

2, 2009
9, 2009

OTHER PUBLICATIONS

4/2002 O'Brien et al.

B1
7/2002 Weiss et al.
B1
7/2002 Bawendi et al.
B1
8, 2003 Bawendi et al.
B1 12/2003 Lakowicz et al.
B1
3, 2004 Weiss et al.
B2 * 1 1/2004 Treadway et al. ........... 428,403
B2
2/2005 Bawendi et al.
B2
7/2005 Chen et al.
B2
5, 2006 Barbera-Guillem
B2 12/2006 Chan et al.
B2
6, 2007 Bawendi et al.
B2
9, 2007 Bawendi et al.

2003/0017264 A1

WO
WO

Agger, J.R. et al., J. Phys. Chem. B (1998) 102, p. 3345.
Aldana, J. et al., J. Am. Chem. Soc. (2001), 123:8844.
Alivisatos, A.P.J. Phys. Chem., (1996), 100, p. 13226.
Alivisatos, A.P.J. Am. Chem. Soc., (1998) 120, p. 5343.
Bawendi, M.G., Annu. Rev. Phys. Chem. (1990), 42:477.
Berry, C.R., Phys. Rev. (1967) 161:848.
Bunge, S.D. et al., J. Mater: Chem. (2003) 13: 1705.
Cumberland et al., “Inorganic Clusters as Single-Source Precursors
for Preparation of CdSe, ZnSe, and CdSe/ZnS Nanomaterials”
Chemistry of Materials, 14, pp. 1576-1584. (2002).
Eychmüller, A. et al., Chem. Phys. Lett. 208, p. 59. (1993).
Fendler, J.H. et al., Adv. Mater. (1995) 7: 607.

2003/0106488 A1

6/2003 Huang et al.

1/2003 Treadway et al.

Gao, M. et al., J. ChemSoc. Commun (1994)2779.

2003/0148024
2004/01 10002
2004/01 10347
2006/006 1017
2006.0118757
2007/0012941

8, 2003
6/2004
6/2004
3f2006
6, 2006
1/2007

Guzelian, A. et al., J. Phys. Chem. (1996) 100: 7212.
Hagfeldt, A. et al., Chem. Rev. (1995) 95: 49.
Henglein, A., Chem Rev. (1989) 89: 1861.
Jegier, J.A. et al., Chem. Mater. (1998) 10.
Kher, S. et al., Chem. Mater. (1994) 6: 2056.
Lieber, C. et al., Angew: Chem. Int. Ed. Engl. (1996) 35: 687.

A1
A1
A1
A1
A1
A1

Kodas et al.
Kim et al.
Yamashita
Strouse et al.
Klimov et al.
Cheon

Guzelian, A. et al., Appl. Phys. Lett. (1996) 69: 1432.

2007/OO58705 A1

3/2007 Wang et al.

LOver, T. et al., J. Mater: Chem. (1997) 7(4): 647.

2007/0059.705 A1
2007, 0104865 A1
2007, 011081.6 A1

3/2007 Lu et al.
5, 2007 Pickett
5, 2007 Jun et al.

Matijevic, E., Ann. Rev. Mater: Sci. (1985) 15:483.
Matijevic, E., Langmuir (1986) 2:12.
Mekis, I. et al., J. Phys. Chem. B. (2003) 107: 7454.

2007/O125983 A1

6/2007 Treadway et al.

Micic et al., “Synthesis and Characterization of InP, GaP, and GalnP

2007/013 1905
2007/0199.109
2007/0202333
2007/0238126

A1
A1
A1
A1

2008.0160306 A1
2008.O220593
2008/0257.201
2008/0264479
2009, O139574
2009, 0212258
2009,0263816

A1
A1
A1
A1
A1
A1

6, 2007
8, 2007
8, 2007
10, 2007

Sato et al.
Yi et al.
O'Brien et al.
Pickett et al.

7/2008 Mushtaq et al.
9, 2008
10, 2008
10, 2008
6, 2009
8, 2009
10, 2009

Pickett et al.
Harris et al.
Harris et al.
Pickett et al.
McCairn et al.
Pickett et al.

FOREIGN PATENT DOCUMENTS
GB
GB
JP
WO
WO
WO
WO
WO
WO
WO
WO
WO
WO
WO
WO
WO
WO
WO
WO
WO
WO
WO
WO
WO
WO
WO
WO
WO
WO

9518910.6
2429838
2005-139389
WO 97.101.75
WO-00-17642
WO-02-004527
WOO2.29.140
WOO3,099708
WO-2004OO8550
WO-2004-066361
WO-2004.0065.362
WO-2005-021150
WO 2004/033366
WO 2005,106082
WO-2005O123575
WO-2006-017125
WO-2006O75974
WO-2006-116337
WO-2006118543
WO-2006O134599
WO-2007020416
WO-2007-049052
WO-2007-060591
WO-2007049052
WO-2007-065039
WO-2007 102799
WO-2008O13780
WO-2008O54874
WO-2008133660

A

A2
A2

A1
A1
A1
A1
A1

A2
A2
A2
A2
A2

9, 1995
3, 2007
6, 2005
3, 1997
3, 2000
1, 2002
4/2002
4/2003
1, 2004
8, 2004
8, 2004
3, 2005
11, 2005
11, 2005
12/2005
2, 2006
T 2006
11, 2006
11, 2006
12/2006
2, 2007
5/2007
5/2007
5/2007
6, 2007
9, 2007
1, 2008
5, 2008
11, 2008

Quantum Dots”, J. Phys. Chem. (1995) pp. 7754–7759.
Murray, C.B. et al., “Synthesis and characterization of nearly
monodisperse CoE (E = Sulfur, selenium, tellurium) semiconductor
nanocrystallites”, J. Am. Chem. Soc. (1993) 115 (19) pp. 8706-8715.

Olshaysky, M.A., et al., J. Am. Chem. Soc. (1990) 1.12: 9438.
Peng et al., “Shape control of CdSe nanocrystals', Nature, (2000)
vol. 404, No. 6773, pp. 59-61.
Pradhan, N. et al., J. Am. Chem. Soc. (2003) 125: 2050.
Qu, L. et al., Nano Lett. (2001) 1: 333.
Salata, O.V. et al., Appl. Phys. Letters (1994) 65: 189.
Sercel, P.C. et al., Appl. Phys. Letters (1992) 61: 696.

Steigerwald, M.L. et al., Acc. Chem. Res. (1990) 23: 183.
Stroscio, J.A. et al., Science (1991), 254: 1319.
Trinidade et al., “A single source approach to the synthesis of CdSe
nanocrystallites'. Advanced Materials, vol. 8, No. 2, pp. 161-163.
(1996).
Wang Y. et al., J. Chem. Phys. (1987) 87:7315.
Weller, H., Adv. Mater. (1993) 5:88.
Weller, H., Angew: Chem. Int. Ed. Engl. (1993) 32: 41.
Wells, R.L. et al., Chem. Mater. (1995) 7:793.
International Search Report for PCT/GB2005/00 1611 mailed Sep. 8,
2005 (5 pages).
Patents Act 1977: Search Report under Section 17 for Application
No. GB0409877.8 dated Oct. 7, 2004 (1 page).
Patent Act 1977 Search Report under Section 17 for Application No.
GB0522027.2 dated Jan. 27, 2006 (1 page).
Arici et al. Thin Solid Films 451-452 (2004) 612-618.
Battaglia et al., “Colloidal Two-dimensional Systems: CodSe Quan
tum Shells and Wells.” Angew Chem. (2003) 115:5189.
Castro et al., “Synthesis and Characterization of Colloidal CuInS2
Nanoparticles from a Molecular Single-Source Precursors.” J. Phys.
Chem. B (2004) 108: 12429.
Castro et al., Chem. Mater. (2003) 15:3142-3147.
Chun et al. Thin Solid Films 480-481 (2005) 46-49.
Contreras et al., “ZnO/ZnS(O,OH)/Cu(ln,Ga)Se /Mo Solar Cell
with 18:6% Efficiency.” from 3d World Conf. on Photovol. Energy
Conv., Late News Paper (2003) pp. 570-573.
Cui et al., “Harvest of near infrared light in PbSe nanocrystal-poly
mer hybrid photovoltaic cells.” Appl. Physics Lett. 88 (2006)
183111-183111-3.

Dance et al., J. Am. Chem. Soc. (1984) 106.6285-6295.
Daniels et al., “New Zinc and Cadmium Chalcogenide Structured
Nanoparticles.” Mat. Res. Soc. Symp. Proc. 789 (2004) pp.31-36.

US 7,803.423 B2
Page 3
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.
Hirpo et al., “Synthesis of Mixed Copper-Indium Chalcogenolates.
Single-Source Precursors for the Photovoltaic Materials CulnO, (Q=
S. Se).” J. Am. Chem. Soc. (1993) 115:1597.
Hu et al., “Hydrothermal preparation of CuGaS crystallites with
different morphologies”. Sol. State Comm. (2002) 121:493-496.
Jiang et al., linorg. Chem. (2000) 39:2964-2965.
Kaelin et 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 Ga Se Solar cells
on rigid and flexible Substrates using nanoparticle precursor inks.”
Thin Solid Films 431-432 (2003) pp. 53-57.
Kim et al., “Synthesis of CuInGaSe Nanoparticles by Low Tempera
ture Colloidal Route”. J. Mech. Sci. Tech. (2005) 19: 2085-2090.
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.
Little et al., “Formation of Quantum-dot quantum-well
heteronanostructures with large lattice mismatch: Zn/CdS/ZnS,” 114
J. Chem. Phys. 4 (2001).
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.
Mews et al., J. Phys. Chem. (1994) 98:934-941.
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.
Nairn et al., Nano Letters (2006) 6:1218-1223.

Yu et al., “Polymer Photovoltaic Cells: Enhanced Efficiencies via a
Network of Internal Donor-Acceptor Heterojunctions,” 270 Science
5243 (1995), pp. 1789-1791.
Zhong et al., "A facile route to synthesize chalcopyrite CuInSe
nanocrystals in non-coordinating solvent 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).
Cao, (2005) “Effect of Layer Thickness on the Luminescence Prop
erties of ZnS/CdS/ZnSquantum dot quantum well'. J. of Colloid and
Interface Science 284:516-520.

Dabousiet 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. lnorg.
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).
Foneberov et al., (2005) “Photoluminescence of tetrahedral quan
tum-dot quantum wells' Physica E, 26:63-66.
Hagfeldt, A. et al. “Light-induced Redox Reactions in Nanocrystal
line Systems”, Chem. Rev. (1995) 95: 49-68.
Harrison et al. (2000) “Wet Chemical Synthesis on Spectroscopic
Study of CdHgTe Nanocrystals with Strong Near-Infrared Lumines
cence” Mat. Sci and Eng.B69-70:355-360.
Huang et al., “Bio-Inspired Fabrication of Antireflection
Nanostructures by Replicating Fly Eyes', Nanotechnology (2008)
vol. 19.

Nazeeruddin et al., "Conversion of Light to Electricity by cis-X

International Search Report for PCT/GB2006/003028 mailed Jan.
22, 2007 (5 pages).
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).
Kim et al. “Engineering InASXP1-X/InP/ZnSe III-V Alloyed Core
Shell Quantum Dots for the Near-Infrared” JACS Articles published

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

Materials Research Society Symposium Proceedings Quantum Dots,
Nanoparticles and Nanowires, 2004, ISSN: 0272-9172.

Bis(2.2 bipyridyl-4,4'-dicarboxylate)ruthenium(II) Charge-Trans
fer Sensitizers (X= Cl, Br, I, CN, and SCN) on Nanocrystalline
TiO, Electrodes.” J. Am. Chem. Soc. (1993) 115:6382-6390.
Nazeeruddin et al., “Engineering of Efficient Panchromatic Sensitiz
ers for Nanocrystalline TiO-Based Solar Cells,” J. Am. Chem. Soc.
(2001) 123:1613-1624.
Novel Asymmetric Dialkydiselenocarbamate.” 3 Chem. Vap. Depos.
4, pp. 2227 (1979).
Olson et al., J. Phys. Chem. C. (2007) 1 11:16640-16645).
Patent Act 1977 Search Report under Section 17 for Application No.
GBO7190754.

Patent Act 1977 Search Report under Section 17 for Application No.
GB0723539.3 dated Mar. 27, 2008.

Patents Act 1977: Search Report under Section 17 for Application
No. GB 0606845.6 dated Sep. 14, 2006.
Patents Act 1977: Search Report under Section 17 for Application No.
GB 0719073.9.

Peng et al., “Kinetics of II-VI and III-V Colloidal Semiconductor
Nanocrystal Growth: "Focusing” os Size Distributions”. J. Am.
Chem. Soc., (1998) 129: 5343-5344.
Peng et al., “Mechanisms of the Shape Evolution of CdSe
Nanocrystals”. J. Am. Chem. Soc. (2001) 123: 1389-1395.
Qi et al., “Efficient polymer-nanocrystal quantum-dot photodetec
tors.” Appl. Physics Lett. 86 (2005) 093103-093103-3.
Robel et al., “Quantum Dot Solar Cells. Harvesting Light Energy
with CdSe Nanocrystals Molecularly Linked to Mesoscopic TiO,
Films,” J. Am. Chem. Soc. (2006) 128: 2385-2393.
Shulz et al., J. Elect. Mat. (1998) 27:433-437.
Vayssieres et al., “Highly Ordered SnO, Nanorod Arrays from Con
trolled Aqueous Growth.” Angew. Chem. Int. Ed. (2004) 43:3666
3670.

Xiao et al., J. Mater: Chem. (2001) 11:1417-1420.
Yang et al., Crystal Growth & Design (2007) 12/2562.

on web Jul. 8, 2005.
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.
Nielsch et al., “Uniform Nickel Deposition into Ordered Alumina
Pores by Pulsed Electrodeposition'. Advanced Materials, 2000 vol.
12, No. 8, pp. 582-586.
Rao et al. (2004) “The Chemistry of Nanomaterials: Synthesis, Prop
erties and Applications' p. 443.
Search Report for GB0813273.0 searched Dec. 8, 2008 (1 page).
Search Report for GB0814458.6 searched Dec. 5, 2008 (1 page).
Search Report for GB0820101.4 searched Mar. 3, 2009 (1 page).
Search Report for GB0821122.9 searched Mar. 19, 2009 (2 pages).
Timoshkin, “Group 13 imido metallanes and their heavier analogs
RMYRI (M=Al, Ga. In;Y=N, PAs, Sb).” Coordination Chemistry
Reviews (2005).
Trinidade et al., “Nanocrystalline Seminconductors: Synthesis, Prop
erties, and Perspectives”. Chemistry of Materials, (2001) vol. 13, No.
11, pp. 3843-3858.
Vittal, “The chemistry of inorganic and organometallic compounds
with adameantane-like structures.” Polyhedron, vol. 15, No. 10, pp.
1585-1642 (1996).
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.
Zhong et al., “Composition-Tunable ZnCu-XSe Nanocrytals with
High Luminescence and Stability”, Jrl Amer. Chem. Soc. (2003).

* cited by examiner

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US 7,803,423 B2
1.

2

PREPARATION OF NANOPARTICLE
MATERALS

non-radiative electron-hole recombinations. One method to

This application is the U.S. national stage application of
International (PCT) Patent Application Serial No. PCT/
GB2005/001611, filed Apr. 27, 2005, which claims the ben
efit of GB Application No. 0409877.8, filed Apr. 30, 2004.
The entire disclosures of these two applications are hereby
incorporated by reference as if set forth at length herein in
their entirety.
There has been substantial interest in the preparation and
characterisation, because of their optical, electronic and
chemical properties, of compound semiconductors consisting

5

in the core from surface states that would otherwise act as
10

little lattice mismatch to that of the core material, so that the

15

shell material can have the reverse effect thus; the lattice

devices" that now range from commercial applications as

indicative of the formation of defects due to breakdown in the

Although some earlier examples appear in the literature.''

25

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

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

30

35

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

40

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 then
the first excitonic transition, are closer together than in the
corresponding macrocrystalline material, so that the Coulom
bic interaction cannot be neglected. This leads to a narrow
bandwidth emission, which is dependent upon the particle
size and composition. Thus, quantum dots have higher kinetic
energy than the corresponding macrocrystalline 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

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 monolayers 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,

diverse as biological labelling, Solar cells, catalysis, biologi
cal imaging, light-emitting diodes amongst many new and
emerging applications.
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

non-radiative recombination centres. 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
interface between the two materials has as little lattice strain

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

Often referred to as quantum dots and/or nanocrystals. These
studies have occurred mainly due to their size-tuneable elec
tronic, optical and chemical properties and the need for the
further miniaturization of both optical and electronic

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

45

50

lattice as a result of high latticed strain. Another approach is
to prepare a core-multi shell structure where the “electron
hole' pair are 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

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.

55

60

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.
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 lead to a number of methods that can

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

method described by Murray, Norris and Bawendi," but use

65

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

US 7,803,423 B2
3
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 crys
tallinity. As mentioned, many variations of this method have
now appeared in the literature which routinely give high
quality core and core-shell nanoparticles with monodispesity
of <5% and quantum yield >50% (for core-shell particles of
as-prepared solutions), with many methods displaying a high

4
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

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

10

15

degree of size' and shape' control.
Recently attention has focused on the use of “greener”

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

precursors include the oxides, CdO;'

carbonates

MCOM-Cd, Zn; acetates M(CHCO),M-Cd, Zn and
acetylacetanates CH-COCH=C(O)CHM-Cd, Zn;

amongst other.'

25

f(The use of the term “greener precursors in semiconductor particle synthesis

has generally taken on the meaning of cheaper, readily available and easier to
handle precursor starting materials, than the originally used organometallics
which are volatile and air and moisture sensitive, 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)

30

35

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

40

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
polar solvent (methanol or ethanol or sometimes acetone) to
produce a precipitate of the particles that can be isolated by
filtration or centrifugation.

45

method by Murray et al" which involves the rapid injection

50

55

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

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

required. However, there are now many reports' II-VI and

60

IV-VI materials being prepared by a similar procedure

GaN, GaP?? GaAs,’ 23, 24, 25, 26, InP27, 28.2°InAs30, 27 and
for PbS and PbSe..?

Fundamentally all these preparations rely on the principle
of particle nucleation followed by growth, moreover, to have
a monodispersed ensemble of nanoparticles there must be
proper separation of nanoparticles nucleation from nanopar

65

precursor's used, continues at the lower temperature and

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 an 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
clusters which Subsequently grow into nanoparticles of
CdS. Strouse and co-workers used a similar synthetic

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
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

US 7,803,423 B2
5
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

5

herein to relate to clusters of 3 or more metal or nonmetal

atoms and their associated ligands of sufficiently well defined
chemical structure such that all molecules of the cluster com

pound possess the same relative molecular mass. Thus the
molecular clusters are identical to one another in the same

way that one HO molecule is identical to another HO 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

10

15

25

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
cluster compound compared to the total number of moles of
the first and second precursor species lies in the range 0.0035

30

35

40

45

50

O.OO45:1.

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:

55

6
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 intention 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
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
mise non-radiative electron-hole recombinations and inhibit

60

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

65

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
ticles.

US 7,803,423 B2
8
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

7
A further way to avoid problems related to non-radiative
electron-hole recombinations 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
than the core material but to have as little lattice mismatch

with the core as possible to minimise lattice strain at the
core-shell interface which could lower quantum efficiencies
due to non-radiative electron-hole recombinations.

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.
The invention consists of the use of molecular clusters as

templates to seed the growth of nanoparticles, whereby other

but is not restricted to:- BP, AlP, AlAs. AlSb; GaN, GaP.
GaAs, GaSb. InN, InP, InAs, InSb, AlN, BN.
10

15

25

SnSe, SnTe.

30

40

45

50

(where L is a capping agent).

55

60

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.
Core-Shell and Core/Multi Shell Particles

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

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 (ZnCdS).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, Sel),L, nanocrystal

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

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

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 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 are not restricted to:—MgS, MgSe, MgTe, CaS,

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, AC, 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,

65

The material used on any shell or Subsequent numbers of
shells grown onto the core particle in most cases will be of a
similar lattice 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

US 7,803,423 B2
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 5
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,

10

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 15
quaternary materials and doped materials. Nanoparticle
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 20
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 25
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:- BP, AlP, AlAs. AlSb; GaN, GaP.
GaAs, GaSb. InN, InP, InAs, InSb, AlN, BN.

30

10
phosphine, t-butylphosphine), 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, monodispersed,
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

III-IV material consisting of a first element from group 13
of the periodic table and a second element from group 16 of (ME), L. particles and L being the coordinating organic
the periodic table and also including ternary and quaternary layer/capping agent, such as a II-VI semiconductor (ZnS),
materials and doped materials. Nanoparticle material include (TOPO), nanoparticle constituting of a ZnScore surrounded
35 by trioctylphosphine oxide ligands (TOPO).
but is not restricted to:—BC, Al C. GaC.
The first step for preparing nanoparticles of a semiconduc
III-VI material consisting of a first element from group 13
of the periodic table and a second element from group 16 of tor material is to use a molecular cluster as a template to seed
the periodic table and also including ternary and quaternary the growth of nanoparticles from other element source pre
materials. Nanoparticle material include but is not restricted cursors. This is achieved by mixing Small quantity of a cluster
to:-Al2S, Al-Se. Al-Tes, Ga-S, Ga-Se. In-S, InSes, 40 which is to be used as the template with a high boiling solvent
which can also be the capping agent, being a Lewis base
Ga-Tes, In-Tes.
IV-VI material consisting of a first element from group 14 coordination compound Such as but not restricted to a phos
of the periodic table and a second element from group 16 of phine, a phosphine oxide or an amine such as TOP TOPO or
the periodic table and also including ternary and quaternary HDA; or an inert Solvent such as a alkane (octadecence) with
materials and doped materials. Nanoparticle material include 45 the addition of a capping agent compound Such as oleic acid.
but is not restricted to:-PbS, PbSe, PbTe, Sb, Tes, SnS,
Further to this a source for M and a source for E (for a ME
SnSe, SnTe.
particle) are added to the reaction mixture. The M and E
Nanoparticle material consisting of a first element from precursor are in the form of two separate precursors one
any group in the transition metal of the periodic table, and a containing M and the other containing E.
second element from any group of the d-block elements of the 50 Further to this other regents may or may not be added to the
periodic table and also including ternary and quaternary reactions which have the ability to control the shape of the
materials and doped materials. Nanoparticle material include nanoparticles grown. These additives are in the form of a
compound that can preferentially bind to a specific face (lat
but is not restricted to:—NiS, CrS, CuInS.
tice plane) of the growing nanoparticle and thus inhibit or
Outer Most Particle Layer
55 slow grow along that specific direction of the particle. Other
Capping Agent
element source precursors may or may not be added to the
The outer most layer (capping agent) of organic material or reaction so as to produce ternary, quaternary or doped par
sheath material is to inhibit particles aggregation and to pro ticles.
tect the nanoparticle from the Surrounding chemical environ
Initially, the compounds of the reaction mixture are
ment and to provide a means of chemical linkage to other 60 allowed to mix on a molecular level at a low enough tempera
inorganic, organic or biological material. The capping agent ture where no particle growth will occur. The reaction mixture
can be the solvent that the nanoparticle preparation is under is then heated at a steady rate until particle growth is initiated
taken in, and consists of a Lewis base compound whereby upon the Surfaces of the molecular cluster-templates. At an
there is alone pair of electrons that are capable of donor type appropriate temperature after the initiation of particle growth
coordination to the Surface of the nanoparticle and can 65 further quantities of M and E precursors may be added to the
include momo- or multi-dentate ligands of the type but not reaction mixture if needed so as to inhibit particles consum
restricted to:- phosphines (trioctylphosphine, triphenol ing one another by the process of Ostward ripening. Further

US 7,803,423 B2
11
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

12

E=S, Se, Te: RCdSR's R=O(CIO), R=PPhs, Pr: CdE.
(EPh), (PR) E, E=Te, Se, S: CdSe(SePh)Cl]:
M.Te M–Cd, Hg: Ph.MsCdo (PEts), M-Te, Se:
II-V: RCdNRL R=C1, Br, I, PEt, C=CSMe: R'=PEt,
I: RCdNR's R-alkyl or aryl group and R-alkyl or aryl

group: {RZn}{PR'al R=I, PEtPh, R'=SiMe: MC1
(PPh)(P"Prs), M-Zn, Cd: Li(thf). (Ph-P)Cd: Zn
(PPh)Cl(PRR), PRR'—PMe"Pra P"Bus, PEtPh: Zn

(PBu)Cl.

10

15

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
ME/NY core-shell material.

25

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

30

35

IIB-VIB:-{(PPh)Hg (SPh):

Cu sTec ("Bu)(PPh.Et), . .
CuoTea (Bu),(PEts):
NiaSe(PPh3); Ago (Te
Ph)Te(PEt); Ago,Ses(Se'Bu) (PnPrs); Co4(LL
Se),(PPh3)]; CO(l-Se)s(PPh3); WSea (dmpe).Br.
Cu, Tes(PPrMe);

MSource
40

45

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:—

50

Organometallic such as but not restricted to a MR where

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

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

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

55

include:—

(PhP)(SEt) (Br)

(HgEBr): (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: DXLEM
(SR), E=S, Se, Te, M=Zn, Cd, Hg: X-MeNH", Li",
EtNH: CdS (SPh).L.: Hg Sea (SePh)(PPh"Pr):
Hg-Sea (SePh); CdoSea (SePh)2(PPrs); CdSea
(SePh) (PPh); M.(SPh)"C. M=Zn, Cd, Hg:
X-Me-N", Li": Zn(SEt)Eto: MeMEiPr M=Zn, Cd, Hg:

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:

RuBi(CO): FeP(CO): FeN(CO)

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.
Examples, clusters to be used but not restricted to

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

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

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

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'=Me H, Br, C=CPh, Pr, (CH), Me,
(CH)2NMe, SiPh: CHGa NCHCH(CH): MeGa
NBul: RGaNR' R=Ph, Me: R'=Ph, CFs, SiMe, Bu:
EtGaNEt: RGaPR'R=Pr, C.H. 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, SiPrs: 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="Bu, CMe Et, CEt: SAIR R=C(SMe),
CEtMe: SAINMes: TeAlR4 R=Cp*, CEtMe: (C
(SiMe))GaSa: TBuGaSI: RGaSea R="Bu, CMeEt,

60

65

Coordination compound Such as a carbonate but not
restricted to a MCO, M=Ca, Sr., Ba, magnesium carbonate
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)CHIM = 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(CHCOO), M-Mg, Ca, Sr, Ba, Zn, Cd, Hg.
Inorganic salt such as but not restricted to a Oxides SrO.
ZnO, CdC). In O, Ga-O. SnO, PbO; Nitrates Mg(NO),

US 7,803,423 B2
13
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.

5

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 spices 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
element include but are not restricted to:—

10

15

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, Ash R, SbH.R. (R-Me, Et, Bu, Bu, Pr, Phetc.);

PH, AsH; M(NMe), MP, Sb, As; dimethyldrazine
(MeNNH); ethylazide (Et-NNN); hydrazine (HNNH);
MeSiN.

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

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, Sb2O, Sb2O, SbOs, BiO, SO, SeO, TeC),
SnO, PbO, PbO; Nitrates Bi(NO), Sn(NO), Pb(NO),

25

30

35

14
FIG. 6) 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 element
Source precursors and with Hexadecylamine used as the cap
ping agent;
FIG. 7) 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 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 Et NHLCdSe (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 EtNHCdSe (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.
Preparation from Et NHLCdSe (SPh)/TOPSe/
(C7HCOO). 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.

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,

EXAMPLES
40

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).Eo; b) RGaSa; c) Bu'GaS, d) IRInSea; and e)
DXLIMoSe(SPh) X=cation, M=Zn, Cd, Te;
FIG. 3) Formation of a Cadmium selenide quantum dot
using MoSea (SPh) XX=Li' or (CH)NH", EtNHas
the molecular seed and cadmium acetate and tri-n-octylphos
phine selenide as the cadmium and selenium element-source
precursors and with Hexadecylamine used as the capping

45

50

55

agent,

FIG. 4) Formation of a Gallium sulfide quantum dot using

TBuGaS), as the molecular seed and gallium(II)acetylaceto

nate and tri-n-octylphosphine Sulfide as the gallium and Sul
fide element-source precursors and with Hexadecylamine
used as the capping agent;
FIG. 5) Formation of a indium selenide quantum dot using
as the molecular seed and Indium(II)acetylacetonate and tri
n-octylphosphine Sulfide as the Indium and selenide element
Source precursors and with Hexadecylamine and tri-n-oc
tylphosphine oxide used as the capping agent;

60

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 (Adrich) were procured commercially and used with
out further purification.
UV-vis absorption spectra were measured on a Hewios?
Thermospectronic. Photoluminescence (PL) spectra were
measured with a Fluorolog-3 (FL3-22) photospectrometer at
the excitation wavelength 380 nm. Powder X-Ray diffraction
(PXRD) measurements were preformed 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
a dynamic vacuum for at lest 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 HNEtCd (SPh)
65

To a stirred methanol (60 ml) solution of benzenethiol
(20.00 g, 182 mmol) and triethylamine (18.50 g., 182 mmol)

US 7,803,423 B2
15
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 CHNSCd C=49.53;

5

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%.
10

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

et al.

To a stirred acetonitrile (100 ml) solution of HNEtCd
(SPh) (80.00g, 45.58 mmol) was added 3.57g 45.21 mmol
of selenium powder, the resulting slurry was left to stir for 12
hours, this produced a white precipitate. A further 750 ml of

15

Example 3
Preparation of CdSe Nanoparticles from Et NHL
CdSe (SPh)/TOP/Se/CdO in HDA

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 acetonitrile. To
give 22.50 g of IHNEtCdSe (SPh). FW=3595.19
Anal. Calc for CHNSeaSCdo. 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

Example 1

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

30

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.

35

40

45

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 EtsNHCdSe (SPh)
(0.311 mmol), TOPSe (1M, 4 ml, 4.00 mmol) previously
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 a hour period. A further 17 ml
(17.00 mmol) of TOPSe and 27 ml of a 0.5M Cd(CHCO)

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 (6.231 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.
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

Example 2
Preparation of CdSe Nanoparticles from Et NHL
CdSe (SPh)/TOPSe/Cd(CHCO), in HDA

16
dissolved in TOP (13.50 mmol) were added dropwise while
the temperature was gradually increased to 200°C. over a 24
h period. The progressive formation/growth of the nanopar
ticles 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 emis
sion 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 in toluene
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.

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 7,803,423 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 Et NHL
CdSe (SPh)/TOPSe/MeCd in HDA
HDA (10 g) was placed in a three-neck flask and 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 8
15

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
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.

40

45

50

55

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

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 Et NHCdSe (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 re-precipitation from
warm ethanol to remove any excess HDA. This produced 0.95
g of HDA capped CdSe nanoparticles.
Example 9

Example 7

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

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

Example 6

HDA (100g) 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.

Preparation of CdTe Nanoparticles from Et NH
CdSe (SPh)/TOPTe/Cd(CHCO), in RDA
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

added 1.0 g of EtNHCdSe (SPh) (0.31 mmol), a
brown slurry of TOP (20 ml) with tellurium (2.55g, 20.00
mmol) along with Cd(CH-CO) (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
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 nanoparticles.
REFERENCES

65

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

US 7,803,423 B2
19
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.

5

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 AEychmüller, A. Mews, and H. Weller, Chem. Phys. Lett.
208, p. 59 (1993).
15 Murray, C.B.; Norris, D. J.; Bawendi, M. G. J. Am. Chem.

10

15

Soc. 1993, 115,8706.

4. A method in accordance with claim 1, wherein the

17X. 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.
25

30

Mater, 1998, 10, 2041.

35

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.

temperature is selected from a range of 50° C. to 70° C.
10. A method in accordance with claim 1, wherein the

method comprises forming a precipitate of the nanoparticle
material by addition of a precipitating reagent.
45

11. A method in accordance with claim 1, wherein the first

precursor species is selected from the group consisting of an
organometallic compound, an inorganic salt, and a coordina
tion compound.
12. A method in accordance with claim 1, wherein the first

50

precursor species is obtained by dissolving in a suitable sol
vent an elemental source selected from the group consisting
of Mg, Ca, Sr., Ba, Zn, Cd, Hg, B, Al. Ga, In, Sn, and Pb.

13. A method in accordance with claim 1, wherein the
55

second precursor species is selected from the group consist
ing of an organometallic compound, an inorganic salt, and a
coordination compound.
14. A method in accordance with claim 1, wherein the

60

second precursor species is obtained by dissolving in a Suit
able solvent an elemental source selected from the group
consisting of Sn, Ge, N. P. As, Sb, Bi, S, Se, Te, Sn and Pb.

15. A method in accordance with claim 1, wherein the

molecular cluster compound comprises a third ion and a
fourth ion to be incorporated into the nanoparticles.

36 Dance, I. G.; Choy, A.; Scudder, M. L. J. Am. Chem. Soc.,
1984, 106, 6285.
The invention claimed is:

1. A method of producing nanoparticles comprising:
effecting conversion of a nanoparticle precursor composi
tion to a material of the nanoparticles, said precursor

ond temperature is selected from a range of 120° C. to 280°C.
7. A method in accordance with claim 1, wherein effecting
conversion of the nanoparticle precursor composition com
prises:
a) monitoring an average size of the nanoparticles being
grown; and
b) terminating nanoparticle growth when the average nano
particle size reaches a predetermined value.
8. A method in accordance with claim 7, wherein nanopar
ticle growth is terminated by reducing the temperature of the
Solution from the second temperature to a third temperature.
9. A method in accordance with claim 8, wherein the third

40

Commun., 1994, 2779.

33 Mekis, I.; Talapin, D. V.: Kornowski, A.; Haase, M.:
Weller, H. J. Phys. Chem. B., 2003, 107,7454.
34LOver, T.; Bowmaker, G. A.; Seakins, J. M.; Cooney, R. P.;
Henderson, W.J. Mater: Chem., 1997, 7(4), 647.

5. A method in accordance with claim 4, wherein the first

temperature is selected from a range of 50° C. to 100° C.
6. A method in accordance with claim 4, wherein the sec

Soc. 2001, 123,8844.
20 Pradhan N.; Efrima S. J. Am. ChemSoc. 2003, 125, 2050;

22 Kher, S. S.; Wells, R. L. Chem. Mater, 1994, 6, 2056.
23 Salata, O. V.; Dobson, P. J.; Hull, P. J.; Hutchison, J. L.
Appl. Phys. Letters 1994, 65, 189.
24 Sercel, P.C.; Saunders, W.A., Atwater, H. A.; Vahala, K.J.;
Flagan, R. C. Appl. Phys. Lett., 1992, 61, 696.
25 Olshavsky, M.A.; Goldstein, A.N.: Alivisatos, A.P.J. Am.
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.;
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.

3. A method in accordance with claim 1, wherein a molar

ratio of the first precursor species to the second precursor
species is selected from a range of 100-1:1.
molecular cluster compound and nanoparticle precursor com
position are dissolved in a solvent at a first temperature to
form a solution and a temperature of the Solution is then
increased to a second temperature Sufficient to initiate seed
ing and growth of the nanoparticles on the molecular clusters
of said compound.

Soc, 1998, 120, 5343.

Qu, L.; Peng, Z. A.; Peng, X. Nano Lett. 2001, 1,333.
21 Jegier, J. A.; McKernan, S.; Gladfelter, W. L. Chem.

2. A method in accordance with claim 1, wherein a ratio of

a number of moles of the cluster compound to a total number
of moles of the first and second precursor species is selected
from a range of 0.0001-0.1:1.

16 A. P. Alivisatos, J. Wickham, X. G. Peng, J. Am. Chem.

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. J. Am. Chem.

20
composition comprising a first precursor species con
taining a first ion to be incorporated into the nanopar
ticles and a separate second precursor species containing
a second ion to be incorporated into the nanoparticles,
wherein said conversion is effected in the presence of a
molecular cluster compound different from the first pre
cursor species and the second precursor species under
conditions permitting seeding and growth of the nano
particles.

16. A method in accordance with claim 15, wherein the
65

third ion is selected from group 12, 13, 14, or 15 or from the
transition metal group of the periodic table and further
wherein:

US 7,803,423 B2
21
(i) if the third ion is selected from group 12 or 13 of the
periodic table, then the fourth ion is selected from group
15 or 16 of the periodic table; and
(ii) if the third ion is selected from group 14 of the periodic
table, then the fourth ion is selected from group 16 of the
periodic table; and
(iii) if the third ion is selected from the transition metal
group of the periodic table, then the fourth ion is selected
from the d-block of the periodic table.
17. A method in accordance with claim 1, wherein the

22
22. A method in accordance with claim 1, wherein the

nanoparticles comprise outer most layers comprising a cap
ping agent.

23. A method in accordance with claim 22, wherein the

capping agent is a solvent in which the nanoparticles are
grOWn.

24. A method in accordance with claim 22, wherein the
10

nanoparticles have cores comprising a core compound com
prising fifth and sixth ions.

18. A method in accordance with claim 17, wherein each

nanoparticle comprises at least one shell grown onto the
nanoparticle core.
19. A method in accordance with claim 18, wherein the at

least one shell has a lattice type similar to a lattice type of the
nanoparticle core.
20. A method in accordance with claim 18, wherein the at

least one shell has a wider band-gap than a band-gap of the
nanoparticle core.
21. A method in accordance with claim 1, wherein the

nanoparticles are ternary phase nanoparticles or quaternary
phase nanoparticles.

15

capping agent is a Lewis base.
25. A method of producing nanoparticles comprising
effecting conversion of a nanoparticle precursor composition
to a material of the nanoparticles, said precursor composition
comprising a first precursor species containing a first ion to be
incorporated into the nanoparticles and a separate second
precursor species containing a second ion to be incorporated
into the nanoparticles, said conversion being effected in the
presence of a molecular cluster compound different from the
first precursor species and the second precursor species under
conditions permitting seeding and growth of the nanopar
ticles, wherein the molecular cluster compound and nanopar
ticle precursor composition are dissolved in a solventata first
temperature to form a solution and the temperature of the
Solution is then increased to a second temperature which is
Sufficient to initiate seeding and growth of the nanoparticles
on the molecular clusters of said compound.
k

k

k

k

k