US 2006006 1017A1 (19) United States (12) Patent Application Publication (10) Pub. No.: US 2006/0061017 A1 Strouse et al. (43) Pub. Date: Mar. 23, 2006

(54) METHOD FOR SYNTHESIS OF COLLOIDAL (22) Filed: Sep. 20, 2004 NANOPARTICLES Publication Classification (75) Inventors: Geoffrey Fielding Strouse, Tallahassee, FL (US); Jeffrey A. Gerbec, Goleta, (51) Int. Cl. CA (US); Donny Magana, Madera, CA B29C 67/00 (2006.01) (US) (52) U.S. Cl...... 264/489 Correspondence Address: (57) ABSTRACT GATES & COOPER LLP HOWARD HUGHES CENTER A method for Synthesis of high quality colloidal nanopar 6701 CENTER DRIVE WEST, SUITE 1050 ticles using comprises a high heating rate proceSS. Irradia LOS ANGELES, CA 90045 (US) tion of Single mode, high power, microwave is a particularly well Suited technique to realize high quality Semiconductor (73) Assignee: The Regents of the University of Cali nanoparticles. The use of microwave radiation effectively fornia automates the Synthesis, and more importantly, permits the use of a continuous flow microwave reactor for commercial (21) Appl. No.: 10/945,053 preparation of the high quality colloidal nanoparticles. Patent Application Publication Mar. 23, 2006 Sheet 1 of 6 US 2006/0061017 A1

U O a O S. - 4.5mm CC Se - - - 5.5nm CC Se s D s N

500 600 Wavelength (nm)

FIG. 1 Patent Application Publication Mar. 23, 2006 Sheet 2 of 6 US 2006/0061017 A1

18 2O

1 O

O O. 8 9. 2. O O 6 B 2 O o f 0. 4.

O 2 7. O. 5 rus

0. O O O 400 500 600 700 Wavelength (nm)

FIG. 2 Patent Application Publication Mar. 23, 2006 Sheet 3 of 6 US 2006/0061017 A1

d . he O ot a. CN 400 450 500 550 600 650 700 600 700 800 Wavelength (nm) Wavelength (nm)

FIG. 3A FIG. 3B Patent Application Publication Mar. 23, 2006 Sheet 4 of 6 US 2006/0061017 A1

30 32

9. al O s s S O d S. iC o

34

400 500 600 700 800 Wavelength (nm)

FIG. 4 Patent Application Publication Mar. 23, 2006 Sheet 5 of 6 US 2006/0061017 A1

PREPAIRE 38 CONSTITUENT ELEMENTS

HIGH-RATE 40 HEATING

42 TEMPERATURE STABILIZATION

HIGH-RATE 44 COOLING

FIG. 5 Patent Application Publication Mar. 23, 2006 Sheet 6 of 6 US 2006/0061017 A1

S. US 2006/0061017 A1 Mar. 23, 2006

METHOD FOR SYNTHESIS OF COLLODAL SUMMARY OF THE INVENTION NANOPARTICLES 0009. To overcome the limitation in the prior art BACKGROUND OF THE INVENTION described above, and to overcome other limitations that will become apparent upon reading and understanding the 0001) 1. Field of the Invention present specification, the present invention describes meth 0002 The invention is related to chemical synthesis of ods of chemical Synthesis of nanoparticles, Such as quantum nanoparticles, and more particularly, to the large-scale, Safe, dots, comprising a high temperature ramp process, warrant convenient, reproducible, energy-conserving Synthesis of ing large-scale, Safe, convenient, reproducible, and energy highly-dispersive inorganic nanoparticles with narrow size efficient production. distribution. 0010. In the present invention, inorganic nanoparticles 0003 2. Description of the Related Art are Synthesized by a Scheme that comprises heating of the 0004 (Note: This application references a number of reaction System. It has been found that the above mentioned different publications as indicated throughout the Specifica limitation can be overcome by including a heating process tion by one or more reference numbers within brackets, e.g., with high ramping rate. Hence, the critical issues that X). A list of these different publications ordered according distinguish the present invention are: to these reference numbers can be found below in the section 0011 (1) a method for synthesizing nanoparticles that entitled “References.” Each of these publications is incor comprises a high temperature ramping rate during heating, porated by reference herein.) 0012 (2) the above mentioned method wherein micro 0005 Over the past decade, numerous advances have wave irradiation is used for the heating process, been made in the Synthetic procedures for formation and isolation of high quality inorganic nanoparticles. These 0013 (3) the above mentioned method wherein the materials are finding applications in a wide range of disci dielectric constant of the main constituent element, which is plines, including optoelectronic devices, biological tagging, the element that dominates the largest amount of molar ratio optical Switching, Solid-State lighting, and Solar cell appli among the entire reactant, is 20 or lower, and cations. 1-11 0014 (4) high crystallinity of the nanoparticles that is 0006. One of the major hurdles for industrialization of often achieved by employing the results of the present these materials has been the development of a reproducible, invention. high quantity Synthetic methodology that is adaptable to high throughput automation for preparation of quantities of BRIEF DESCRIPTION OF THE DRAWINGS >100's of grams of single size (<5% RMS) crystalline 0015 Referring now to the drawings in which like ref quantum dots of various composition to be isolated. 12-13 erence numbers represent corresponding parts throughout: 0007. The general synthetic approach for preparation of colloidal Semiconductor nanoparticles employs a bulky 0016 FIG. 1 is a graph that illustrates the absorption and reaction flask under continuous Ar flow with a heating photoluminescence for 4.5 nm and 5.5 nm CdSe; mantle operating in excess of 240 C. The reaction is 0017 FIG. 2 is a graph that illustrates the absorption and initiated by rapid injection of the precursors, which are the photoluminescence for 4.6 mm CdSe; Source materials for the nanoparticles, at high temperatures and growth is controlled by the addition of a strongly 0018 FIGS. 3A and 3B are graphs that illustrate the coordinating ligand to control kinetics. And to a more absorption and photoluminescence of InGaP nanocrystals limited extent, domestic microwave ovens have been used to synthesized with hexadecene (HDE) and octadecene as the Synthesize nanoparticles. 14-19 The high temperature non-coordinating Solvents, method imposes a limiting factor for industrial Scalability and rapid nanomaterial discovery for Several reasons: (1) 0019 FIG. 4 is a graph that illustrates the absorption and random batch-to-batch irregularities Such as temperature photoluminescence of InGaP showing the dependence of ramping rates and thermal instability; (2) time and cost crystallinity on power; required for preparation for each individual reaction; and (3) 0020 FIG. 5 is a flowchart that illustrates the processing low product yield for device applications. StepS used in the preferred embodiment of the present 0008 While recent advances in the field have developed invention; and better reactants, including inorganic Single Source precur 0021 FIG. 6 is an illustration of the processing steps Sors, metal Salts, and oxides, better passivants, Such as used in the preferred embodiment of the present invention. amines and non-coordinating Solvents, and better reaction technologies, Such as thermal flow reactors, the reactions are DETAILED DESCRIPTION OF THE still limited by reproducibility. Coupled to this problem is INVENTION the lack of control over reaction times, which require continuous monitoring. In the case of III-V compound 0022. In the following description of the preferred Semiconductors, the Synthetic pathways have rates of growth embodiment, reference is made to the accompanying draw on the order of days, while in the case of II-VI's, size control ings which form a part hereof, and in which is shown by way is very difficult and depends on the ability to rapidly cool the of illustration a specific embodiment in which the invention reaction. In these cases, the reaction depends on heating rate, may be practiced. It is to be understood that other embodi heat uniformity over the reaction vessel, Stirring and rapid ments may be utilized and Structural changes may be made and uniform cool-down. without departing from the Scope of the present invention. US 2006/0061017 A1 Mar. 23, 2006

0023 1. The Reaction System free of any heat input/output. Here, Stable temperature refers to processes in which the temperature change is 5 C./min or 0024. In the present invention, nanoparticles are synthe leSS. sized by heating the reaction System from room temperature to elevated temperatures. The reaction System herein is a 0031 Cool-down of the reaction system can be achieved closed System that consists of materials that are necessary by removing heat from the System by Standard means Such for the synthetic reaction. Each of these materials will as air, , ice, oil or cryogenic gas. Microwave irradiation hereafter be called a constituent element. In the most primi with or without other heat Sources can be used to control this tive reaction System, the Sole constituent element is the cool-down process. The average cooling rate of each cool precursor. However, in general, the constituent elements are down process is defined as: Solvent and precursor. The Solvent can be a mixture of plural (Temperature at the beginning of cooling ( C.)-Tem Solvents, and also the precursor can be a mixture of plural perature at the end of cooling( C.))/(Duration of precursors. These elements can either be dispersed homo cooling (min)) geneously or inhomogeneously. 0032. The synthetic scheme described in the present invention comprises one or more Stages of high cooling rate. 0.025 The constituent elements of the reaction system are Here, high cooling rate refers to a rate of 80 C./min or mixed at or near room temperature and heated for nanopar higher, more preferably 85 C/min or higher, most favor ticle synthesis. Here, near room temperature is below 100 ably 90° C./min or higher. When the average cooling rate is C. below 80 C./min, synthesis may result in nanoparticulate 0.026 2. Heating and Cooling of the Reaction System materials with unfavorable properties Such as lower disperS ibility or wider size distribution. Hereinafter, this high rate 0027. In the present invention, the temperature of the cooling proceSS may be referred to as quenching. Hence, the reaction System is typically monitored by devices Such as Simplest embodiment of the present invention for Synthe thermometer, pyrometer, or thermocouples. The reaction sizing nanoparticles comprise of three Stages that are high described in the present invention comprise one or more of rate heating, temperature Stabilization, and high-rate cool each of the (1) heating at a high heating rate, (2) Stabilization Ing. at elevated temperature, and (3) cooling at a high cooling rate. 0033 3. Additives to the Reaction System 0034. In order to control the heating and cooling rates of 0028. As a specific feature in one of the preferred the reaction System, additives can be intentionally intro embodiments, heating of the reaction System is performed duced to the System as a constituent element. In general, by microwave irradiation. 20-23 The heating of the reac there is no limitation to the nature of Such additives, and can tion System can either be achieved by Sole use of microwave be either organic or inorganic materials. The additives can or with the aid of other heat Sources Such as oil-bath, either be dispersed homogeneously or inhomogeneously in mantle-heater, or burners. The frequency of the microwave is typically 2.45 GHz but not limited. Use of focused the reaction System. Moreover, the additives can be present microwave is preferred over unfocused, and Single-mode is in the reaction System from the beginning of the process or preferred over multimode for efficient heating. Ramping the can be introduced during the course of the reaction. temperature of the reaction System up is done Solely by Examples of Such additives are: graphite, Silicon carbide, microwave irradiation or microwave irradiation with the use glycols, ionic liquids, tetrabutylammonium bromide and of additional heat Sources, during which the heating rate can cholesterols. be controlled by the input power of the microwave by a 0035) Furthermore, for synthesizing the same or different continuous or pulsed power Supply. The average heating rate nanoparticles, in addition to the precursors that exist in the during each process of the Synthesis is defined as: reaction System, one may further introduce the same or (Temperature at the end of heating(C.)-Temperature different precursors during the course of reaction. at the beginning of heating(C.))/(Duration of heating 0036 4. The Main Constituent Elements of the Reaction (min)) System 0029. The synthetic scheme described in the present invention comprises one or more Stages of high heating rate. 0037 AS described above, the reaction system comprises Here, high heating rate refers to a rate of 30° C./min or one or more constituent elements. The main constituent higher, more preferably 32 C./min or higher, most favor element is the element with the largest molar equivalent. In ably 34 C./min or higher. When the average heating rate is the present invention, the dielectric constant of the main below 30° C./min, synthesis may result in nanoparticulate constituent element is 20 or less, preferably 18 or less, more materials with unfavorable properties Such as lower disperS preferably 16 or less, and most preferably 14 or less. If the dielectric constant is over 20, it may result in loss of stability ibility or wider size distribution. of the precursors in the System due to the exceedingly high 0.030. During the stage where the temperature is stable at polarity of the main constituent element. Additives can be elevated temperature, heating by microwave irradiation with introduced into the System before or during the course of or without other heat Sources is performed together with reaction as long as their amounts are less than the main cooling by using means as flow of air or water, ice, oil or constituent element in molar equivalent. cryogenic gas, to balance the input/output of heat to/from the system to hold the temperature constant. When the heat 0038) 5. Nanoparticles capacitance of the reaction System is large enough Such that 0039 The nanoparticles synthesized by the method the change in the temperature can be ignored, temperature described in the present invention comprise mainly inor Stabilization may be achieved by merely leaving the System ganic materials, and their diameters are on the order of US 2006/0061017 A1 Mar. 23, 2006

nanometers (nm). The main crystal may be single crystal, of Group 8 and Group 16 elements, such as Fe0, FeS, FeSe polycrystal, alloys with or without phase Separation due to and RuS, compounds of Group 7 and Group 16 elements, Stoichiometric variations, or core-shell Structures that will be such as MnO, MnS, MnSe and ReS, compounds of Group 6 described later. The average diameter of Such crystals are and Group 16 elements, Such as Cr-S, Cr-Sea and MoS, 0.5-100 nm, preferably 1-20nm in order to warrant dispers compounds of Group 5 and Group 16 elements, Such as VS, ibility, more preferably 2-12mm, most preferably 2-10nm. VSe, and NbS, compounds of Group 4 and Group 16 Such diameters can be determined through characterization elements, Such as TiO, TIS, and ZrS, compounds of by transmission electron microscopy (TEM). When the Group 2 and Group 16 elements, such as BeO, MgS, and micrographs cannot be obtained with Sufficient contrast to CaSe, and chalcogen spinnels, barium titanates (BaTiO). make Such determination of the diameter, for instance when the constituent atoms are those of low atomic numbers, 0043 7. Core-Shell Structures techniques Such as matrix assisted laser desorption ioniza 0044) The crystals that form the main body of the nano tion spectroscopy, atomic force microscopy (AFM), or for particles of the present invention can be the So-called colloidal Solutions, dynamic light Scattering or neutron core-shell Structure in which the crystals comprise inner Scattering can often be used instead. core and Outer-Shell for modification of their physical and 0040. While there is no limitation in the size distribution chemical properties. Such shells are preferably metal, Semi of the above mentioned nanoparticles, in general, the Stan conductor, or insulator. AS for Semiconductor, examples of dard deviation is +20%, preferably +15%, more preferably preferred materials are compounds of Group 13 and Group +10%, and most preferably +5%. When the size distribution 15 elements, such as ME (where M=B, Al, Ga, In and E=N, exceeds the above, the nanoparticles will often not exhibit P, AS, Sb) and compounds of Group 12 and Group 16 their desired physical and chemical properties to their best elements, such as MA (where M=Zn, Cd, Hg and A=O, S, performance. Methods that are typically used to characterize Se, Te) and compounds of Group 2 and Group 16 elements, the crystallinity of the nanoparticles are dark field transmis such as TA(where T=Be, Mg, Ca Sr, Ba and A=O, S, Se, Te). Sion electron microScopy which is used to look for glide Examples of more preferred materials for the shells are III-V plane defects and/or twinning. Powder X-ray diffraction, compound semiconductors, such as BN, BAS, or GaN, II-VI which reveals the approximate diameters and shapes of the compound Semiconductors, Such as ZnO, ZnS, ZnSe, CdS, crystallites through peak intensities and Scherrer broadening compounds of Group 12 and Group 16 elements, Such as of the reflection peaks. Finally, Z-contrast transmission elec MgS, or MgSe. tron microScopy is used to image the dopant ion in nano 0045 8. Doping of Nanoparticles particle alloys. 0046. In the compositions described above in sections 5 0041 6. The Composition of Semiconductor Nanopar and 6, minute amounts of additives can be intentionally ticles doped for modification of the physical and chemical prop 0042. When the nanoparticles synthesized by the method erties of the nanoparticles. Examples of Such doping mate described in the present invention are Semiconductor, there rials are Al, Mn, Cu, Zn, Ag, Cl, Ce, Eu, Th, Er, or Tm. is no limitation in their composition, but typical examples 0047 9. Organic Compounds Present at the Nanoparticle are single Substances of Group 14 elements, Such as C, Si, Surface Ge, or Sn, Single Substances of Group 15 elements, Such as 0048. The nanoparticles synthesized by the method P (black phosphorus), single Substances of Group 16 ele described in the present invention can have organic com ments, Such as Se or Te, compounds of Group 14 elements, pounds attached to their Surface. The attachment of organic Such as SiC, compounds of Group 14 and Group 16 ele compounds to the Surface is defined as the State in which the ments, Such as GeS, GeSe, GeTe, SnS, SnSe, SnTe, PbS, organic compound is chemically bonded to the Surface. PbSe, or PbTe, and their ternary and quaternary alloys, such While there is no limitation in the form of bonding between as GeSn-S,Se (x=0-1, y=0-1), compounds of Group the organic compound and the nanoparticle Surface, 13 and Group 15 elements, such as AlN, AlP, AlAS, AISb, examples are coordination bond, covalent bond, relatively GaN, GaP, GaAs, GaSb, InN, InP, InAS, or InSb, and their Strong bonds Such as ionic bond, or through relatively weak ternary and quaternary alloys, Such as Ga, In, PAS interaction Such as Van der Waals force, hydrogen bond, (x=0-1, y=0-1), compounds of Group 13 and Group 16 hydrophobic-hydrophobic interaction, or entanglement of elements or their alloys, such as GaS, GaSe, GaTe, InS, InSe, InTe, TIS, TISe, TITe, and their ternary and quaternary molecular chains. The organic compounds can be a single alloys, such as Gain-S, Sei (X=0-1, y=0-1), compounds Species or a mixture of two or more. of Group 13 and Group 17 elements, such as TIC1, TIBr, TII, 0049. In general, in order to attach to the nanoparticle compounds of Group 12 and Group 16 elements, Such as Surface, organic compounds consist of the following coor ZnS, ZnSe, ZnTe, CdS, CdSe, CdTe. HgS, HgSe, HgTe, and dinating functional groups that form bonds to the nanopar their ternary and quaternary alloys, such as Zn, CdS,Sey ticle Surface. Typically, coordinating functional groups that (x=0-1, y=0-1), compounds of Group 15 and Group 16 comprise Group 15 or Group 16 elements constitute the elements, Such as AS2S3, ASS, AS2Sea, AS-Tes, Sb2S3, above mentioned organic compounds. Examples of Such SbSea, SbTe, BiS, Bi-Sea, BiTes, and their ternary and functional groups are, primary amines, Secondary amines, quaternary alloys, compounds of Group 11 and Group 16 tertiary amines, radicals containing nitrogen multiple bonds, elements, Such as CuO, Cu2O, AgS and CuSe, compounds Such as nitryl, or isocyanate, nitrogen containing radicals of Group 11 and Group 17 elements, such as CuCl, AgBr and Such as nitric aromatics, Such as pyridine or triazine, func AuCl, ccompounds of Group 10 and Group 16 elements, tional groups containing Group 15 element Such as phos such as NiS, PdS and Pt.Se, compounds of Group 9 and phorus containing radicals, Such as primary phosphine, Group 16 elements, such as CoSe, RhS and IrSe, compounds Secondary phosphine, tertiary phosphine, primary phosphine US 2006/0061017 A1 Mar. 23, 2006 oxide, Secondary phosphine oxide, tertiary phosphine oxide, dihalides, Such as magnesium , halides of Group 4 primary phosphine Selenide, Secondary phosphine Selenide, elements, such as titanium (IV) tetrachloride, titanium (IV) tertiary phosphine Selenide, or phosphonic acid, oxygen tetrabromide, or titanium (IV) tetraiodide; halides of Group containing radicals, Such as hydroxyl, ether, or carboxyl, 5 elements, such as vanadium (II) dichloride, vanadium (IV) Sulfur containing radicals, Such as thiol, methylsulfide, eth tetrachloride, vanadium (II) dibromide, vanadium (IV) tet ylsulfide, phenylsulfide, methyldisulphide, phenyldisulfide, rabromide, vanadium (II) diiodide, vanadium (IV) tetraio thioacid, dithioacid, Xanthogenic acid, Xanthete, isothiocy dide, tantalum (V) pentachloride, tantalum (V) pentabro anate, thiocarbamate, Sulfonic, Sulfoxide, or thiophene rings, functional groups containing Group 16 element Such as mide, and tantalum (V) pentaiodide; halides of Group 6 Selenium containing radicals, Such as -SeH, -SeCH, elements, such as chromium(III) tribromide, chromium(III) -SeCHs, or tellurium containing radicals, Such as -TeH, triiodide, molybdenum (IV) tetrachloride, molybdenum (IV) -TeCH, -TeCHs. Among these examples, functional tetrabromide, molybdenum (IV) tetraiodide, tungsten (IV) groups containing nitrogen Such as pyridine rings, functional tetrachloride, tungsten (IV) tetrabromide, and tungsten (IV) groups containing Group 15 elements Such as phosphorus, tetraiodide, halides of Group 7 elements, Such as manganese Such as primary amine, tertiary phosphine, tertiary phos (II) dichloride, manganese (II) dibromide, and manganese phine oxide, tertiary phosphine Selenide, or phosphonic acid, (III) diiodide; halides of Group 8 elements, such as iron (II) functional groups containing oxygen, Such as hydroxyl, dichloride, iron (III) trichloride, iron (II) dibromide, iron ether, or carboxyl, or functional groups containing Group 16 (III) tribromide, iron (II) diiodide, and iron (III) triiodide; elements Such as Sulfur, Such as thiol or methylsulfide, are halides of Group 9 elements, such as cobalt(II) dichloride, used preferably. More precisely, trialkylphosphines, trialky cobalt (II) dibromide, and cobalt (II) diiodide; halides of lphosphine oxides, alkane Sulfonic acids, alkane phosphonic Group 10 elements, such as nickel(II) dichloride, nickel(II) acids, alkyl amines, dialkylsulfoxides, dialkylether, and dibromide, and nickel (II) diiodide; halides of Group 11 alkylcarboxyl acids are Such examples. elements, Such as copper (I) iodide; dialkylated compounds of Group 12 elements, Such as dimethyl Zinc, diethyl Zinc, 0050. While the detailed coordination chemistry of these di-n-propyl Zinc, diisopropyl Zinc, di-n-butyl Zinc, diisobu organic compounds on the nanoparticle Surface is not totally tyl Zinc, di-n-hexyl Zinc, dicyclohexyl Zinc, dimethyl cad understood, in the present invention, as long as the nano mium, diethyl cadmium, dimethyl mercury (II), diethyl particle Surface is covered with these organic compounds, mercury (II), and dibenzyl mercury (II); alkyl halides of the functional groups may either retain their original Struc Group 12 elements, Such as methyl Zinc chloride, methyl ture or be modified. Zinc chloride, methyl Zinc iodide, ethyl Zinc iodide, methyl cadmium chloride, and methyl mercury (II) chloride; diha 0051 10. The Amount of Organic Compounds at the lides of Group 12 elements, Such as Zinc chloride, Zinc Nanoparticle Surface bromide, Zinc iodide, cadmium chloride, cadmium bromide, 0.052 In the present invention, the amount of organic cadmium iodide, mercury(II) chloride, Zinc chloride iodide, compounds present at the Surface depends on the kind of cadmium chloride iodide, mercury (II) chloride iodide, Zinc nanoparticles and their Surface area, Such as their size, after bromide iodide, cadmium bromide iodide, and mercury (II) proper Separation, among the total weight of the nanopar bromide iodide, carboxylic acid Salt of Group 12 elements, ticles and the organic compounds, is typically 1 to 90% of Such as Zinc acetate, cadmium acetate, and 2-ethylhexanoic the weight, and for chemical Stability and in order to acid cadmium; oxides of Group 12 elements, Such as cad disperse them into organic matrices Such as Solvents or resin mium oxide and Zinc oxide, trialkylated compounds of binders that are practically important preferably. 5-80%, Group 13 elements, Such as trimethyl , tri-n-propyl more preferably, 10-70%, and most preferably 15-60%. boron, triisopropyl boron, trimethyl aluminum, trimethyl The above mentioned organic composition can be deter aluminum, triethyl aluminum, tri-n-butyl aluminum, tri-n- mined, for example, by the various elemental analyses or hexyl aluminum, trioctyl aluminum, tri-n-butyl gallium (III), thermogravimetric analysis (TGA). Furthermore, informa trimethyl indium (III), triethyl indium (III), and tri-n-butyl tion regarding the chemical Species and environment can be indium (III); dialkyl monohalides of Group 13 elements, obtained by infrared (IR) spectroscopy or nuclear magnetic Such as dimethyl aluminum chloride, diethyl aluminum resonance (NMR). chloride, di-n-butyl aluminum chloride, di-ethyl aluminum bromide, di-ethyl aluminum iodide, di-n-butyl gallium (III) 0053) 11. Precursors chloride, or di-n-butyl indium (III) chloride; monoalkyl 0.054 When the nanoparticles synthesize by the method dihalides of Group 13 elements, Such as methyl aluminum described in the present invention are Semiconductor, cat dichloride, ethyl aluminum dichloride, ethyl aluminum ionic materials that can be chosen from elements in Group dibromide, ethyl aluminum diiodide, n-butyl aluminum 2-15 and anionic materials that can be chosen from elements dichloride, n-butyl gallium (III) dichloride, and n-butyl in Group 15-17 can be used as precursors. When more than indium (III) dichloride; tri-halides of Group 13 elements, one material is used, they may be mixed prior to the Such as , , boron triiodide, Synthetic reaction or may be separately introduced into the aluminum trichloride, aluminum tribromide, aluminum tri reaction System. iodide, gallium (III) trichloride, gallium (III) tribromide, gallium (III) triiodide, indium (III) trichloride, indium (III) 0.055 Examples of the precursors for semiconductors that tribromide, indium (III) triiodide, gallium (III) dichloride contain cationic elements are, dialkylated compounds of bromide, gallium (III) dichloride iodide, gallium (III) chlo Group 2 elements, Such as diethyl magnesium, or di-n-butyl ride diiodide, and indium (III) dichloride iodide; carboxylic magnesium; alkyl halides of Group 2 elements, Such as acid Salt of Group 13 elements, such as indium (III) acetate methyl magnesium chloride, methyl magnesium bromide, and gallium (III) acetate; halides of Group 14 elements, Such methyl magnesium iodide, ethynyl magnesium chloride; as germanium (IV) tetrachloride, germanium (IV) tetrabro US 2006/0061017 A1 Mar. 23, 2006 mide, germanium (IV) tetraiodide, tin (II) dichloride, tin 17 elements, such as trimethylsilyl chloride, trimethylsilyl (IV) tetrachloride, tin (II) dibromide, tin (IV) tetrabromide, bromide, and trimethysilyl iodide, etc. Among the above, tin (II) diiodide, tin (IV) tetraiodide, tin (IV) dichloride more preferably used materials are, elemental materials in diiodide, tin (IV) tetraiodide, lead (II) dichloride, lead (II) Groups 15 and 16, Such as phosphorus, arsenic, antimony, dibromide, and lead (II) diiodide; hydrates of Group 14 Sulfur, and Selenium; Sillylated compounds of Group 15 elements, Such as diphenyl Silane; trialkyls of Group 15 elements, Such as tris(trimethylsilyl) phospine and tri(trim elements, Such as trimethyl antimony (III), triethyl antimony ethylsilyl) arsine; silylated compounds of Group 16 ele (III), tri-n-butyl antimony (III), trimethyl bismuth (III), ments, such as bis(trimethylsilyl)sulfide and bis(trimethyl triethyl bismuth (III), and tri-n-butyl bismuth (III); monoalkyl halides of Group 15 elements, Such as methyl silyl) selenide; alkaline metal salts of Group 16 elements, antimony (III) dichloride, methyl antimony (III) dibromide, Such as Sodium Sulfide and Sodium Selenide, trialkylphos methyl antimony (III) diiodide, ethyl antimony (III) diio phine chalcogenides Such as, tributylphosphine Sulfide, trio dide, methylbismuth(III) dichloride, and ethylbismuth(III) ctylphosphine Sulfide, tributylphosphine Selenide, and trio diiodide, trihalides of Group 15 elements, Such as arsenic ctylphosphine Selenide; etc. (III) trichloride, arsenic (III) tribromide, arsenic (III) trio 0058 Examples of precursors for metal nanoparticles for dide, antimony (III) trichloride, antimony (III) tribromide, group 4 through 13 including Au, Ag, Fe, Ni, Co, Pt, Pd, Cu, antimony (III) triiodide, bismuth (III) trichloride, bismuth Hg, In, NiPt, FePt, FeCo are: Gold: auric acid, chlorocar (III) tribromide, and bismuth(III) triiodide; etc. bonyl gold (I, and gold (I) chloride; Silver: silver (I) acetate, 0056. For synthesis of nanoparticles of Group 14 elemen silver (I) nitrate, silver (I) chloride, silver (I) bromide, silver tal SemiconductorS Such as Si, Ge, or Sn, halides of Group (I) iodide, and silver sulfate; Iron (either as II or III oxidation 14 elements, Such as germanium (IV) tetrachloride, germa State): iron chloride, iron bromide, iron iodide, iron (O) nium(IV) tetrabromide, germanium(IV) tetraibdide, tin (II) carbonyl, iron acetate, iron acetyl acetonate, iron hexapyri dichloride, tin (IV) tetrachloride, tin(II) dibromide, tin (IV) dine, iron hexamine, iron Sterate, iron palmitate, iron Sul tetrabromide, tin (II) diiodide, tin (IV) diiodide, tin (IV) fonate, iron nitrate, iron dithiocarbamate, iron dodecylsul dichloride diiodide, tin (IV) tetraiodide, lead (II) dichloride, fate, and iron tetrafluroborate; Nickel: nickel (II) nitrate, lead(II) dibromide, and lead(II) diiodide; or hydrides and/or nickel (II) chloride, nickel(II) bromide, nickel (II) iodide, alkylated compounds of Group 14 elements, Such as diphe nickel (II) carbonyl, nickel (II) acetate, nickel (II) acetyl nyl Silane, can be used as precursors. acetonate, nickel (II) hexapyridine, nickel (II) hexamine, 0057 Examples of anionic compounds that can be used nickel(II) sterate, nickel(II) palmitate, nickel(II) sulfonate, as precursors for Semiconductors are, elements of Groups nickel (II) nitrate, nickel (II) dithiocarbamate, nickel (II) 15-17, Such as N, P, AS, Sb, Bi, O, S, Se, Te, F, Cl, Br, and dodecylsulfate, and nickel (II) tetrafluroborate; Cobalt: I, hydrides of Group 15 elements, Such as ammonia, phos cobalt(II) nitrate, cobalt(II) chloride, cobalt(II) bromide, phine (PH), arsine (ASH), and stibine (SbH); silylated cobalt(II) iodide, cobalt (II) carbonyl, cobalt (II) acetate, compounds of elements of Group 15 of the periodic table, cobalt (II) acetyl acetonate, cobalt (II) acetyl acetonate Such as tris(trimethylsilyl) amine, tris(trimethylsilyl) phos cobalt (II) hexapyridine, cobalt (II) hexamine, cobalt (II) phine, and tris(trimethylsilyl) arsine; hydrides of Group 16 sterate, cobalt(III) palmitate, cobalt(II) sulfonate, cobalt(II) elements, Such as hydrogen Sulfide, hydrogen Selenide, and nitrate, cobalt (II) dithiocarbamate, cobalt (II) dodecylsul hydrogen telluride; Sillylated compounds of Group 16 ele fate, and cobalt(II) tetrafluroborate; Platinum: platinum (II) ments, such as bis(trimethylsilyl)sulfide and bis(trimethyl nitrate, platinum (II) chloride, platinum (II) bromide, plati silyl) selenide, alkaline metal Salts of Group 16 elements, num (II) iodide, platinum carbonyl, platinum (II) acetate, Such as Sodium Sulfide and Sodium Selenide, trialkylphos platinum (II) acetyl acetonate, platinum (II) hexapyridine, phine chalcogenides, Such as tributylphosphine Sulfide, tri platinum (II) hexamine, platinum (II) Sterate, platinum (II) hexylphosphine Sulfide, trioctylphosphine Sulfide, tribu palmitate, platinum (II) sulfonate, platinum (II) nitrate, tylphosine Selenide, trihexylphosphine Selenide, and platinum (II) dithiocarbamate, platinum (II) dodecylsulfate, trioctylphosphine Selenide, hydrides of Group 17 elements, and platinum (II) tetrafluroborate; Palladium: palladium (II) Such as hydrogen fluoride, hydrogen chloride, hydrogen nitrate, palladium (II) chloride, palladium (II) bromide, bromide, and , and Sillylated compounds of palladium (II) iodide, palladium carbonyl, palladium (II) Group 17 elements, such as trimethylsilyl chloride, trimeth acetate, palladium (II) acetyl acetonate, palladium (II) ylsilyl bromide, and trimethylsilyl iodide, etc. Among these, hexapyridine, palladium (II) hexamine, palladium (II) Ster from the Stand points of reactivity, Stability, and handling, ate, palladium (II) palmitate, palladium (II) sulfonate, pal the preferred materials are, elemental materials in Groups ladium (II) nitrate, palladium (II) dithiocarbamate, palla 15-17, Such as phosphorus, arsenic, antimony, bismuth, dium (II) dodecylsulfate, and palladium(II) tetrafluroborate; Sulfur, Selenium, tellurium, and , Sillylated compounds Copper (I or II oxidation state): copper nitrate, copper of Group 15 elements, Such as tris(trimethylsilyl) phospine chloride, copper bromide, copper iodide, copper carbonyl, and tri(trimethylsilyl) arsine; hydrides of Group 16 ele copper acetate, copper acetyl acetonate, copper hexapyri ments, Such as hydrogen Sulfide, hydrogen Selenide and dine, copper hexamine, copper Sterate, copper palmitate, hydrogen telluride; Sillylated compounds of Group 16 ele copper Sulfonate, copper nitrate, copper dithiocarbamate, ments, such as bis(trimethylsilyl)sulfide and bis(trimethyl copper dodecylsulfate, and copper tetrafluroborate; Mer silyl) selenide; alkaline metal salts of Group 16 elements, cury:, dimethyl mercury (0), diphenyl mercury (O), mercury Such as Sodium Sulfide and Sodium Selenide, trialkylphos (II) acetate, mercury (II) bromide, mercury (II) chloride, phine chalcogenides Such as, tributylphosphine Sulfide, tri mercury (II) iodide, and mercury (II) nitrate; Indium: trim hexylphosphine Sulfide, trioctylphosphine Sulfide, tribu ethyl indium (III), indium (III) dichloride, indium (III) tylphosphine Selenide, trihexylphosphine Selenide, and trichloride, indium (II) tribromide, and indium (III) trio trioctylphosphine Selenide; Sillylated compounds of Group dide. US 2006/0061017 A1 Mar. 23, 2006

0059) 12. Solvents groups. For example, 5 ml of technical grade hexadecy 0060. The solvent effect for nanoparticle formation under lamine can be dielectrically heated at 300 W to 280° C. in dielectric heating is twofold: (1) it provides the matrix for 11 minutes with 1 atm of pressure. In the Same manner, which the reactants form products; and (2) they have the trioctylphosphine oxide can be dielectrically heated to 280 ability to absorb microwaves to intrinsically heat the reac C. in 15 seconds with 1 atm of pressure. tion matrix. The matrix effect can be noncoordinating or coordinating in nature. Noncoordinating implies that the 13. EXAMPLES Solvent does not form bonds to the precursor molecules or 0068 AS provided hereunder, embodiments of the intermediate complexes during nanoparticle formation (it present invention will be illustrated in more detail by ways usually does not have functional groups). Coordinating of examples, although the present invention is not limited to implies the Solvent forms bonds to the precursor molecules these examples provided that the outcome is within the gist and intermediates during nanoparticle formation. of the present invention. 0061 Noncoordinating solvents used for nanoparticle 0069. With regard to the material reagents, commercially formation usually consist of long chain, high boiling alkanes available reagents were used without purification unless and alkenes Such as hexadecane, octadecane, eicosane, otherwise Stated. 1-hexadecene, 1-octadecene and 1-eicosene. Typical coor dinating Solvents consist of long chain (backbone of 6 to 20 0070) Instrument Setup, Conditions, etc., for Measure carbons) alkyl amines (primary, Secondary and tertiary), ment carboxylic acids, Sulfonic acids phosphonic acids, phos 0071 (1) Microwave assisted synthesis setup: phines and phosphine oxides. 0072 a. DISCOVER system, CEM Corporation, 0062) The ability for a solvent to absorb microwaves is NC, U.S.A. highly dependant on its dipole moment. The dipole moment is defined as the product of the distance between two charges 0073) b. MILESTONE ETHOS system (continuous and the magnitude of the charge; hence, when a coordinating and pulsed power Supply), Milestone Corporation, Solvent is used as the Solvent, it has a higher propencity of Monroe, Conn., U.S.A. heating the bulk Solution faster than a noncoordinating 0074) (2) UV/v is absorption spectroscopy: CARY solvent that has a lower dipole moment by definition. When 50BIO WIN UV Spectrometer. comparing the heating rates of trioctylphosphineoxide (760 C./min) to 1-aminohexadecane (30° C./min), trioctylphos 0075 (3) Photoluminescence spectroscopy: CARY phineoxide converts electric energy to heat more efficiently. ECLIPSE Fluorescence Spectrometer. Comparing these to the heating rate of tetradecene (12 0076) (4) X-ray diffractometry: SCINTAG X2 powder C./min) shows that the choice of solvents has a substantial diffractometer. influence on the rate at which the heat is transferred to the bulk Solution. 0077 (5) Transmission electron microscopy: JEOL 2010 Transmission Electron Microscope 0.063. One way to slow down the rate of heating for a Solvent that absorbs microwave Strongly, like trioctylphos 0078 General Procedure phineoxide, is to reduce the incident microwave power. This 0079 The duration of nanoparticle reactions have been will allow the ramp rate to be tailored to Suite a particular optimized to 15 minutes at a maximum temperature of 280 nanoparticle formation. C. It is shown that under the influence of microwave 0.064 Technical grade solvent dielectric heating rates for radiation, the crystallinity becomes dependant on the power nanoparticle Synthesis will depend on Several factors: the of the radiation in concert with the temperature of the dielectric constant, the Volume of Solvent, and its boiling reaction. The microwave reactor allows the precursors to be point. For nonpolar Solvents Such as C-C straight chain prepared at or near room temperature (RT) and loaded into alkanes, the heating rates are slow for 5 ml of solvent at 300 a reaction vessel prior to its introduction into an RT chamber W of incident power. of the microwave reactor. The reaction vessel is then heated to temperatures between 200° C. and 300° C. with active 0065 For example, Super-heated noncoordinating tech cooling. The microwave reactor operates at 2.45 GHZ and nical grade octane plateaus at 147 C. after 15 minutes of can be adapted to a continuous flow or autoSampler System. heating at 300W with 10 atm of pressure. However, in the Incorporation of integrated absorption and fluorescent detec presence of Cd and Se monomers (57 mM), Super-heating tors allow the reaction Stream to be continuously monitored octane can reach nanoparicle formation temperatures as high for applications where high throughput, high Volume prepa as 250° C. in 6 minutes with 15 atm of pressure with 300 W of incident microwave power. ration of colloidal Semiconductor nanoparticles is desired. 0080. In a typical small scale synthesis (5 ml or less), the 0.066 The lower boiling point alkanes will have a lower reactants are mixed in a high-pressure reaction vessel and plateau temperature in terms of the maximum Sustained placed in the RT chamber of the microwave reactor. The temperature at high pressure. The higher boiling alkanes can reaction is controlled by a predetermined program that achieve higher temperatures in a shorter period of time when controls and monitorS reaction time, temperature, pressure, compared to alkanes. When 5 ml of technical grade tet and microwave power (wattage) in real time. These reaction radecene is dielectrically heated at 300 W, it can reach 250 parameters control material size, purity, crystallinity, and C. in 13 min. dispersity. The Synthetic protocol allows reproducible pro 0067 Coordinating solvents typically heat faster at lower duction of materials. The isolation and Storage of the mate preSSure due to their higher boiling points and functional rials can be done directly inside the high-pressure reaction US 2006/0061017 A1 Mar. 23, 2006 vessel, thereby eliminating the Step of material transfer that later use. The anion Solution was prepard by mixing 182 mg potentially exposes the materials to contaminants Such as of 200 mesh Se powder in 2.8 ml TOP The coordinating oxygen and water. The Teflon liner in the chamber of the solvent, trioctyphosphine oxide (TOPO), was degassed microwave reactor was re-designed from typical commer under vacuum at 110° C. three times and back filled with Ar cial Specifications in order to tolerate high temperatures for over a two hour period. The Cd (0.5 ml) and Se (0.6 ml) were extended periods of time. The reaction vessel comprises a 5 mixed in a teflon sealed reaction vial, and diluted with 3.9 ml vial with a high-pressure aluminum crimp top with Teflon ml molten TOPO (approximately 65° C) to make a 5 ml Septa. All glassware was dried prior to use. All reagents were Solution. The reaction vessel was placed in the chamber of manipulated by Standard airleSS techniques. the microwave reactor at room temperature. 300 Watts were applied for Several Seconds, at which time the temperature 0081. In a typical large scale reaction (5 ml or greater), spiked from 40°C. to 230 C. in 15 seconds. The power was the reactants are placed in a Standard round bottom flask reduced to 40 Watts to stabilize the temperature at 250 C. (Kirmax, Pyrex or Chemglass) and placed in a RT chamber for 8 minutes. At 8 minutes, the power was turned off and the and irradiated with continuous or pulsed power with dual reaction was quenched. This resulted in a 4.6 mm CdSe magnetrons until the desired temperature is reached. nanoparticle, approximated by the excitonic peak position, Example 1 as shown in FIG. 2, wherein traces 18 and 20 represent the absorption and photoluminescence, respectively, of CdSe Preparation of CdSe From a Single Source Precur grown from cadmium nitrate and trioctylphosphineselenide. Note that nanoparticle diameter can be tuned by reaction Sor LiLCdSe (SPh), temperature. 0082 It has been shown by Cumberland et al. in 7 that a novel single Source precursor based upon Li 0087 High heating rate: 760° C./min CdSe (SPh) in the presence of mild coordinating alkyl 0088 Main constituent of the reactant (Dielectric con amine Solvent can yield CdSe quantum dots in the Size range stant): TOPO (<20) of 2-9 nm with a reaction time of 720 minutes on average. Using this Single Source precursor in the presence of hexa 0089 Ref: Dielectric constants of materials similar to decylamine (HDA) microwave irradiation yields nanopar TOPO 24, 25 ticles in a fraction of the time. 0.083 50 g of HDA was degassed under vacuum at 110 C. 80 mg of LiCdoSea (SPh) was placed in the reaction Dielectric vessel and Sealed with a high pressure crimp cap followed by Temp.( C.) Const. the addition of 4 ml of molten, degassed HDA (at approxi Triethylphosphine oxide (C.H.S)P=O 323.2 35.5 mately 70° C.). The reaction vessel was placed in the Tributylphosphine oxide (CH)P=O 323.2 26.4 chamber of the microwave reactor and irradiated with 300 Triheptylphosphine oxide (C7Hs). P=O 323.2 30.4 Watts of power until it reached 230 C., at which time the Trioctylphosphine oxide (CH)P=O TOPO --19 power was decreased to 230 Watts. This power and tem Trinonylphosphine oxide (CHo).P=O 323.2 15.4 perature was held constant for 60 minutes. At 60 minutes, the power was turned off and the latent heat of the reaction vessel was quickly removed by passing compressed air Example 3 across it. This produced monodisperse 4.5 nm to 5.5 nm CdSe nanoparticles. Smaller sizes can be isolated under Preparation of InP From InCOAc) and P(SiMe.) these experimental parameters simply by quenching the 0090 The preparation of the stock precursor solutions reaction at Shorter time intervals. Increasing the microwave was done according to literature methods, Such as those in power to 250 Watts for 60 minutes at 230 C. can yield sizes 9. A Solution of indium acetate and hexadecanoic acid was larger than 4.5 nm, e.g., 5.5 nm, as shown in FIG. 1, wherein prepared in hexadecene. The mole ratio of In to hexade traces 10 and 12 represent the absorption and photolumi canoic acid was adjusted to a 1 to 3. The Salts were dissolved nescence, respectively, of 4.5 nm CdSe synthesized at 230 at 100° C. to make a 15.6 mM solution in In. The solution C. and 230W, while traces 14 and 16 represent the absorp was degassed at this temperature for 1 hour and purged with tion and photoluminescence, respectively, of 5.5 nm CdSe Ar three times. A stock solution of tris(trimethylsilyl) phos grown at 230° C. and 250W. phine at 86.1 mM was prepared in dry hexadecene. 0084) High heating rate: 30° C./min 0091. The In and P precursors were mixed at 50° C. in a 0085 Main constituent of the reactant (Dielectric con 10 ml Sealed reaction vessel in a 2:1 ratio to make a total stant): Hexadecylamine (2.71).5 volume of 5 ml precursor Solution. The reaction vessel was irradiated with 300 watts of power until the solution reached Example 2 a temperature of 280 C. The power was reduced to maintain 280 watts. This temperature and power was maintained for Preparation of CdSe From CdNO3 and TOP:Se 15 minutes, at which time the reaction was rapidly quenched. 0.086 Stock solutions of Cd and Se were prepared sepa rately. The cation Solution was prepared by dissolving 435 0092 High heating rate: 30° C./min mg of cadmium nitrate tetrahydrate in 9.6 ml of trioctylphos phine (TOP). This solution was heated to 100° C. under 0093 Main constituent of the reactant (Dielectric con Vacuum for 30 minutes. The reaction mixture was purged stant): Hexadecene (2.1-2.2) with Arthree times and then cooled to room temperature for 0094 (Ref: Dielectric constant of 1-tridecene is 2.139) US 2006/0061017 A1 Mar. 23, 2006

0.095 Ref: Dielectric constants of materials similar to synthesized at 280 C. for 15 minutes at 280 Watts. Traces hexadecane 24 22 and 26 represent InCap synthesized with hexadecene (HDE) as the non-coordinating solvent, and traces 24 and 28 represent InGaP Synthesized with octadecene as the non coordinating Solvent. Temp.( C.) Dielectric Const. 1-Hexene CH12 2.94.O 2.007 0103) An important feature of the specific microwave 1-Heptene C7H1 293.2 2.092 effect on III-V ternary compound crystal growth is that the 1-Octene C8H16 293.2 2.113 crystallinity (optical properties of the final product) is 1-Nonene CoH1s 293.2 2-18O dependant on the microwave power. If the reaction time and 1-Decene CoHoo 293.2 2.136 1-Undecene C11H22 293.2 2.137 temperature are held constant while the power is reduced, 1-Dodecene C12H24 293.2 2.152 low energy defect emission begins to form, as shown in 1-Tridecene C13H25 293.2 2.139 FIG. 4. 0104 FIG. 4 illustrates the absorption and photolumi neScence of InCapshowing the dependence of crystallinity Example 4 on power, wherein trace 30 represents the absorption for InGaP and trace 32 represents the photoluminescence for Preparation of InCaP From InCOAc), Ga (acac), InGaP that were synthesized with a constant power of 230 and P(SiMe.) watts, while trace 34 represents the absorption for InCap and 0096. The stock solution was prepared by a modification trace 36 represents the photoluminescence for InCap that of literature methods 9). Indium III acetate (0.700 mmol), were synthesized at a constant power of 270 watts. gallium III 2.4-pentanedionate (0.070 mmol) and hexade 0105 The defect emission can be attributed to surface canoic acid (2.30 mmol) were mixed with 50 ml either vacancies or glide plane defects. It is clear that not only high octadecene or hexadecene. The mixture was heated to 160 temperature is important for high quality material, but high C. until the solution turned clear. The temperature of the stock solution was reduced to 110° C. under vacuum and power is needed as well. The Structural characterization of purged with Ar three times. the material exhibits the Zinc blende structure of bulk InP. 0097. For 4.8 nm quantum dots, the cation stock solution 0106) 14. Processing Steps was prepared with octadecene and mixed with tris(trimeth 0107 FIG. 5 is a flowchart that illustrates the processing ylsilyl)phosphine in the reaction vessel via syringe at 50° C. Steps for Synthesizing nanoparticles used in the preferred with a cation: anion mole ratio of 2:1. 5 ml of the stock embodiment of the present invention. These StepS are typi solution was placed in a 10 ml sealed reactor vial (CEM). cally performed using a Single reaction vessel, continuous The 2.3 nm quantum dots were prepared in the same fashion, flow reactor or Stopped flow reactor. but the Stock Solution was prepared in hexadecene. 0.108 Block 38 represents the step of preparing one or 0.098 Reactor temperature and pressures were monitored more constituent elements at or near room temperature, continuously to ensure Safety, with preSSures not exceeding wherein the room temperature is below 100° C. Preferably, 1.7 atm during the course of the reaction. The power level a dielectric constant of a main one of the constituent of the ramp was 300 watts. The hold temperature was 280 elements is 20 or higher. C. for 15 min., with a constant power level of 280 watts during the reaction. To ensure controlled dispersity, the 0109 Block 40 represents the step of heating the pre reaction vessel was rapidly cooled, via a quenching Oswald pared constituent elements to an elevated temperature using Ripening process, from 280 C. to 95 C. over a period of high-rate heating, in order to create a reaction mixture. 2 min using compressed air. Depending on the concentration Preferably, the heating Step is performed using microwave of precursors, the ramp rate to achieve the hold temperature irradiation, and the high heating rate comprises a rate of 30 ranged from 4-6 minutes with the more dilute Samples C./min or higher. taking longer, due to the heating arising from direct dielec tric heating of the precursors, rather then the thermal heating 0110 Block 42 represents the step of stabilizing the of the Solvent. Size control for these materials was achieved reaction mixture at the elevated temperature. Preferably, the by controlling the concentration of the constituent elements elevated temperature is greater than 240 C. in the reactant. 0111 Block 44 represents the step of cooling the stabi 0099 High heating rate: 32° C./min lized reaction mixture to a reduced temperature using high rate cooling. Preferably, the high cooling rate comprises a 0100 Main constituent of the reactant: octadecene rate of 125 C./min or higher. (Dielectric constant estimated to be 2.1-2.2) 0112 FIG. 6 is an illustration of the processing steps for 0101 When hexadecene was used as the non-coordinat Synthesizing nanoparticles used in the preferred embodi ing solvent, approximately 2.3 nm InCap was grown. When ment of the present invention. AS noted above, the reactor 46 octadecene was used as the non-coordinating Solvent, 4.8 typically comprises a single reaction vessel, continuous flow nm nanoparticles were grown. The Size is determined by reactor or stopped flow reactor. The reactant 48 includes the Scherrer broadening of the powder X-ray diffraction peaks, consituent elements, Such as one or more precursors 50 and as shown in FIGS. 3A and 3B. 52 that contain elements that turn into nanoparticles, passi 0102 FIG. 3A illustrates the absorption and FIG. 3B vants 54, and/or solvents 56. Arrow 58 represents the illustrates the photoluminescence of InGaP nanoparticles heating/cooling process that creates the nanoparticles 60. US 2006/0061017 A1 Mar. 23, 2006

15. REFERENCES 0133). 20 C. Gabriel, S. Gabriel, E. H. Grant, B. S. J. 0113. The following references are incorporated by ref Halstead, D. M. P. Mingos, Chemical Society Reviews erence herein: 1998, 27, 213. 0134) 21 E. T. Thostenson, T. W. Chou, Composites 0114 1) R. L. Wells, S. R. Aubuchon, S. S. Kher, M. S. Part a-Applied Science and Manufacturing 1999, 30, Lube, P. S. White, Chemistry of Materials 1995, 7, 793. 1055. 0115 (2 O. I. Micic, C. J. Curtis, K. M. Jones, J. R. Sprague, A.J. Nozik, Journal of Physical Chemistry 1994, 0135) 22 D. A. Jones, T. P. Lelyveld, S. D. Mavrofidis, S. W. Kingman, N. J. Miles, Resources Conservation and 98, 4966. Recycling 2002, 34, 75. 0116 (3 O. I. Micic, J. R. Sprague, C. J. Curtis, K. M. Jones, J. L. Machol, A. J. Nozik, H. Giessen, B. Fluegel, 0.136 23 A. Loupy, Microwaves in organic synthesis, G. Mohs, N. Peyghambarian, Journal of Physical Chem Wiley-VCH, Weinheim; Cambridge, 2002. istry 1995, 99,7754. 0137 24 D. R. Lide, ed., CRC Handbook of Chemistry 0117 4A. A. Guzelian, J. E. B. Katari, A. V. Kadavan and Physics, 76th Ed., CRC 1995 pp. 6-159. ich, U. Banin, K. Hamad, E. Juban, A. P. Alivisatos, R. H. 0138 25 Bogovikov, U. Y., et al., Zh. Obchei Himi Wolters, C. C. Arnold, J. R. Heath, Journal of Physical 1969, 40, pp. 1957-1962. Chemistry 1996, 100, 7212. 0139) 16. Conclusion 0118 5 O. I. Micic, S. P. Ahrenkiel, A. J. Nozik, Applied Physics Letters 2001, 78, 4022. 0140. This concludes the description of the preferred embodiment of the present invention. In Summary, the 0119) 6 Z.A. Peng, X. G. Peng, Journal of the American present invention has shown that colloidal nanoparticles can Chemical Society 2001, 123, 183. be rapidly Synthesized under high power microwave radia 0120) 7 S.L. Cumberland, K. M. Hanif, A. Javier, G. A. tion to provide industrial Scalability with no Sacrifice to Khitrov, G. F. Strouse, S. M. Woessner, C. S. Yun, Structural integrity or optical quality. Chemistry of Materials 2002, 14, 1576. 0.141. The foregoing description of one or more embodi 0121 8 D. V. Talapin, A. L. Rogach, I. Mekis, S. ments of the invention has been presented for the purposes Haubold, A. Kornowski, M. Haase, H. Weller, Colloids of illustration and description. It is not intended to be and Surfaces a-Physicochemical and Engineering Aspects exhaustive or to limit the invention to the precise form 2002, 202, 145. disclosed. Many modifications and variations are possible in light of the above teaching. It is intended that the Scope of 0.122 9 D. Battaglia, X. G. Peng, Nano Letters 2002, 2, the invention be limited not by this detailed description, but 102.7 rather by the claims appended hereto. 0123 10 J. J. Li, Y.A. Wang, W. Z. Guo, J. C. Keay, T. D. Mishima, M. B. Johnson, X. G. Peng, Journal of the What is claimed is: American Chemical Society 2003, 125, 12567. 1. A method for chemically Synthesizing nanoparticles, comprising a heating process of a reaction System, which 0.124. 11 I. Mekis, D. V. Talapin, A. Kornowski, M. comprises precursors, passivants, and/or Solvents in a reac Haase, H. Weller, Journal of Physical Chemistry B 2003, tor, in which a temperature of constituent elements is ramped 107, 7454. at 30° C./min or higher. 0125 12 E. M. Chan, R. A. Mathies, A. P. Alivisatos, 2. The method of claim 1, wherein microwave irradiation Nano Letters 2003, 3, 199. is used for the heating process. 3. The method of claims 1 or 2, wherein a dielectric 0126 13 H. Z. Wang, X. Y. Li, M. Uehara, Y. Yamagu constant of a main constituent element is 20 or lower. chi, H. Nakamura, M. P. Miyazaki, H. Shimizu, H. 4. A method for chemically Synthesizing nanoparticles, Maeda, Chemical Communications 2004, 48. wherein a dielectric constant of a main constituent element 0127 14 C. C. Landry, J. Lockwood, A. R. Barron, is 20 or lower. Chemistry of Materials 1995, 7, 699. 5. The method of claims 1, 2, 3 or 4, wherein the nanoparticles are metal, Semiconductor, or insulator. 0128 15 A. V. Murugan, R. S. Sonawane, B. B. Kale, 6. The nanoparticles of claim 5. S. K. Apte, A. V. Kulkarni, Materials Chemistry and 7. The nanoparticles of claim 6, wherein the nanoparticles Physics 2001, 71,98. have organic or inorganic compounds attached to their 0129) 16. H. Grisaru, O. Palchik, A. Gedanken, V. Surface. Palchik, M. A. Slifkin, A. M. Weiss, Journal of Materials 8. A method for Synthesizing nanoparticles, comprising: Chemistry 2002, 12, 339. preparing one or more constituent elements at or near 0130 17 J. He, X. N. Zhao, J. J. Zhu, J. Wang, Journal room temperature; of Crystal Growth 2002, 240, 389. heating the prepared constituent elements to an elevated 0131 18 T. Ding, J. R. Zhang, S. Long, J. J. Zhu, temperature using high-rate heating, in order to create Microelectronic Engineering 2003, 66, 46. a reaction mixture; 0132) 19 E. H. Hong, K. H. Lee, S. H. Oh, C. G. Park, Stabilizing the reaction mixture at the elevated tempera Advanced Functional Materials 2003, 13,961. ture; and US 2006/0061017 A1 Mar. 23, 2006 10

cooling the Stabilized reaction mixture to a reduced tem- 12. The method of claim 8, wherein the high heating rate perature using high-rate cooling, comprises a rate of 30° C./min or higher. So that nanoparticles are Synthesized. 13. The method of claim 8, wherein the high cooling rate 9. The method of claim 8, wherein a dielectric constant of comprises a rate of 80 C. /min or higher. a main constituent element is 20 or. lower. 14. Nanoparticles grown according to the method of claim 10. The method of claim 8, wherein the room temperature 8 is below 100° C. 11. The method of claim 8, wherein the heating step is performed using microwave irradiation. k . . . .