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

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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)

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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 U.S. Patent ŽIJ (I Sep. 28, 2010 Sheet 1 of 14 US 7,803.423 B2 U.S. Patent Sep. 28, 2010 Sheet 2 of 14 US 7,803.423 B2 U.S. Patent Sep. 28, 2010 Sheet 3 of 14 US 7,803.423 B2 U.S. Patent Sep. 28, 2010 US 7,803.423 B2 Sheet 4 of 14 | la | U.S. Patent Sep. 28, 2010 Sheet 5 of 14 US 7,803.423 B2 U.S. Patent US 7,803.423 B2 U.S. Patent Sep. 28, 2010 Sheet 7 of 14 US 7.803.423 B2 U.S. Patent Sep. 28, 2010 Sheet 8 of 14 US 7,803.423 B2 8 N - C S g S wr s - 9 9 S SP S o O N v- y v- we s v- C d r N O ; : w (ne) (Sueu S U.S. Patent US 7.803.423 B2 U.S. Patent Sep. 28, 2010 Sheet 10 of 14 US 7,803.423 B2 U.S. Patent Sep. 28, 2010 Sheet 11 of 14 O|0o-8 co co t vt o c (ne) A Sueu US 7.803.423 B2 U.S. Patent Sep. 28, 2010 Sheet 14 of 14 US 7,803.423 B2 00A 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

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