Abstract: There is disclosed a process of making nano-sized or micro-sized precipitate particles. The process comprising the steps of mixing, in a reaction zone, a metal salt solution with a precipitant solution to form a precipitate, said precipitate being at least one of a metal chalcogenide, metal hydroxide and metal oxide; and applying a shear force to said mixing solutions in said reaction zone during said mixing step, wherein said shear force and the conditions within said reaction zone form said nano-sized or micro-sized precipitate particles.

Abstract: A method for producing a thiometallate or selenometallate material is provided in which a first salt containing an anionic component selected from the group consisting of MoS42?, MoSe42?, WS42?, WSe42? and a second salt containing a cationic component comprising copper in any non-zero oxidation state are mixed under anaerobic conditions in an aqueous mixture at a temperature of from 50° C. to 150° C.

Abstract: The present invention is directed to a manganese tetrathiotungstate composition.

Abstract: A multi-element metal chalcogenide and a method for preparing the same are provided. The multi-element metal chalcogenide includes multiple metal elements. A multi-element metal chalcogenide powder is prepared, and all of the multiple metal elements of the multi-element metal chalcogenide are derived from at least one of simple substance powders of the metal elements and one or more alloy powders mixed in accordance with a mole ratio. A solution phase synthesis of the powder of the multi-element metal chalcogenide is then conducted under normal pressure to prepare the multi-element metal chalcogenide. The multi-element metal chalcogenide can be coated to obtain a film or used to make a target and then bombard the target for sputtering a film. In such a way, a selenization process which is conventional in fabricating the semiconductor solar cell is eliminated, thus improving production yield and efficiency.

Abstract: The present invention provides a process for obtaining fullerene-like metal chalcogenide nanoparticles, comprising feeding a metal precursor selected from metal halide, metal carbonyl, organo-metallic compound and metal oxyhalide vapor into a reaction chamber towards a reaction zone to interact with a flow of at least one chalcogen material in gas phase, the temperature conditions in said reaction zone being such to enable the formation of the fullerene-like metal chalcogenide nanoparticles product. The present invention further provides novel IF metal chalcogenides nanoparticles with spherical shape and optionally having a very small or no hollow core exhibiting excellent tribological behaviour. The present invention further provides an apparatus for preparing various IF nanostructures.

Abstract: A method for preparing III-VI2 nanoparticles and a thin film of polycrystalline light absorber layers. The method for preparing I-III-VI2 nanoparticles comprises the steps of: (a1) preparing a mixed solution by mixing each element from groups I, III and VI in the periodic table with a solvent; (a2) sonicating the mixed solution; (a3) separating the solvent from the sonicated mixed solution; and (a4) drying the product resulted from the above step (a3) to obtain nanoparticles.

Abstract: A blue light emitting semiconductor nanocrystal having an quantum yield of greater than 20% can be incorporated in a light emitting device.

Abstract: A method for producing hydrogen from a light hydrocarbon gas with the hydrocarbon gas being converted to particulate carbon and hydrogen and thereafter quenched with liquid sulfur with the purified hydrogen being recovered as a product.

Abstract: The invention is directed to a process for the manufacture of a ceria based polishing composition, comprising (a) suspending an inorganic cerium salt or cerium hydroxide with a cerium content calculated as cerium oxide in the range of 50%-100% based on Total rare earth oxide (TREO) in an aqueous medium thereby obtaining an aqueous suspension, (b) treating said aqueous suspension with an acid or a salt of an acid selected from the group of HF, H3PO4 and H2SO4, thereby obtaining a solid suspended in said aqueous medium, (c) separating said solid from said aqueous medium, and (d) calcining the separated solid at a temperature between 750° C. and 1,200° C. and grinding the calcined solid to grain sizes in the range of 0.5 ?m to 5.0 ?m.

Abstract: A method for preparing a chalcopyrite-type semiconductor compound which is widely used as a sunlight-absorbing material. More specifically, disclosed is a method for preparing a chalcopyrite-type compound, in which microwaves are used as heat sources in the preparation of the chalcopyrite-type compound, and the chalcopyrite-type compound can be produced in a large amount in a short reaction time using a batch or continuous reactor.

Abstract: Mixing small amounts of an inorganic halide, such as NaCl, to basic copper carbonate followed by calcination at a temperature sufficient to decompose the carbonate results in a significant improvement in resistance to reduction of the resulting copper oxide. The introduction of the halide can be also achieved during the precipitation of the carbonate precursor. These reduction resistant copper oxides can be in the form of composites with alumina and are especially useful for purification of gas or liquid streams containing hydrogen or other reducing agents. These reduction resistant copper oxides can function at near ambient temperatures.

Abstract: A nanoparticle composition is disclosed comprising a copper indium gallium selenide, a copper indium sulfide, or a combination thereof. Also disclosed is a layer comprising the nanoparticle composition. A photovoltaic device comprising the nanoparticle composition and/or the absorbing layer is disclosed. Also disclosed are methods for producing the nanoparticle compositions, absorbing layers, and photovoltaic devices described herein.

Abstract: CuInS2 nanoparticles have been prepared from single source precursors via microwave irradiation. Also, CuInGaS2 alloy nanoparticles have been prepared. Microwave irradiation methods have allowed an increase in the efficiency of preparation of these materials by providing increased uniformity of heating and shorter reaction times. Nanoparticle growth has been controlled in the about 1 to 5 nm size range by variation of thiolated capping ligand concentrations as well as reaction temperatures and times. Investigation of the photophysical properties of the colloidal nanoparticles has been performed using electronic absorption and luminescence emission spectroscopy. Qualitative nanoparticles sizes have been determined from the photoluminescence (PL) data and compared to TEM images.

Abstract: Related are a copper indium sulfide nanoparticle and a preparation method thereof. Copper salts, indium salts and alkane thiol are added to a non-polar organic solvent, and then are heated with stirring under inert gas atmosphere to dissolve until a dark red colloidal solution is obtained. The obtained colloidal solution is cooled to room temperature, and then a polar solvent is added. The copper indium sulfide semiconductor nanoparticles are obtained through centrifugal settling. The obtained copper indium sulfide semiconductor nanoparticles could be further washed and vacuum dried to give copper indium sulfide semiconductor nanoparticle powders. The obtained copper indium sulfide semiconductor nanoparticles have an average particle size of 2 to 10 nm and an emission spectrum of 600 to 800 nm in the near infrared region, quantum efficiency being close to 10%. The yield of the present method is up to 90%.

Abstract: Hydrogen sulfide H2S is prepared from a crude gas stream containing H2S and polysulfanes (H2Sx). The crude gas stream is passed at temperatures of from 114 to 165° C. through catalytically active material present in a vessel, and sulfur is collected in the bottom of the vessel and recycled to the preparation of H2S. This process may be accomplished in an apparatus including a reactor for reacting sulfur and hydrogen, a cooler for receiving and cooling an H2S-containing crude gas stream passed out of the reactor to between 114 to 165° C., a vessel coupled to the cooler, the vessel including catalytically active material and a bottom for collecting sulfur obtained from the crude gas stream, and a line which is connected to the bottom of the vessel and opens into the cooler or into the reactor, for recycling sulfur.

Abstract: A method for synthesizing a chalcogenide nanoparticle is provided. The method comprises reacting a metal component with an elemental chalcogen precursor in the presence of an organic solvent. The chalcogenide nanoparticles include ternary, binary and/or multinary chalcogenide nanoparticles and the metal component comprises metal halides or elemental metal precursors. The alkylamine solvent has a normal boiling temperature of above about 220° C. and an average particle size of from about 5 nm to about 1000 nm.

Abstract: The present disclosure provides a solid dopant for doping a conductive polymer, which has a high dispersibility in a solvent by a plasma treatment, a method and an apparatus for preparing the solid dopants, a solid doping method of a conductive polymer using the solid dopants, and a solid doping method of a conductive polymer using plasma.

Abstract: Process of making high purity, synthetic FeS2, and an electrochemical battery employing such synthetic FeS2 in the positive electrode. Synthetic FeS2 may be prepared by a sulfidation process comprising reacting ferric oxide, hydrogen sulfide, and elemental sulfur at a temperature above the melting point of element sulfur. Synthetic FeS2 may also be produced by a milling process that comprises (i) milling iron powder and sulfur powder in the presence of a milling media and a processing agent to provide a homogenous powder mixture, and (ii) treating the powder mixture to form FeS2. In the milling process, the powder mixture may be treated to form FeS2 by heating the powder mixture or subjecting the powder mixture to a subsequent milling operation.

Abstract: The invention relates to the use, in the manufacturing of materials or devices for photonic applications, of chalcogenide-type compounds having an octahedrally coordinated indium element and wherein a transition element is introduced in octahedral position generating a partially occupied intermediate band separate from those of valence and conduction of the initial semiconductor, according to quantum mechanics calculations. This enables, by absorption of two photons having energy lower than the prohibited bandwidth of the initial semiconductor, a result equivalent to that achieved, without said intermediate band, by the absorption of a higher-energy photon. The use of such a material can thereby improve yield and performance of various photovoltaic, photocatalytic, photoelectrochemical, optoelectronic or photonic conversion devices. Indium sulfide substituted in part with vanadium or titanium is one of the specific materials having these properties that is synthesised according to the invention.

Abstract: Methods of processing nanocrystals to remove excess free and bound organic material and particularly surfactants used during the synthesis process, and resulting nanocrystal compositions, devices and systems that are physically, electrically and chemically integratable into an end application.

Abstract: Soluble chalcogenido clusters together with transition metal ions and main group elements are shown to provide gels having interconnected, open frameworks. Following supercritical drying with liquid carbon dioxide, the chalcogels may be converted to aerogels. The aerogels possess high internal surface areas with a broad pore size distribution that is dependent upon the precursors used and the aging conditions applied. Some of the gels are encompassed by formulas such as M4[M?4Qx]n, M4[M?2Qy]n, M4[M?Qx]n, M3[M?Qx]n, or Me2[M??Qx]n, where M is a divalent, trivalent, or tetravalent metal ion; M?, M?, and M?? are typically Ge, Sn, P, As, Sb, Mo, or W; and Q is typically S, Se, or Te. Methods of preparing the chalcogenido clusters are also provided.

Abstract: A method for preparing III-VI2 nanoparticles and a thin film of polycrystalline light absorber layers. The method for preparing I-III-VI2 nanoparticles comprises the steps of: (a1) preparing a mixed solution by mixing each element from groups I, III and VI in the periodic table with a solvent; (a2) sonicating the mixed solution; (a3) separating the solvent from the sonicated mixed solution; and (a4) drying the product resulted from the above step (a3) to obtain nanoparticles.

Abstract: Devices and components that can interact with or modify propagation of electromagnetic waves are provided. The design, fabrication and structures of the devices exploit the properties of reactive composite materials (RCM) and reaction products thereof.

Abstract: The invention provides a preparation method of Zn1-xCdxA quantum dot capable of emitting white light, in which A is S or S1-ySey; 0<x<1 and 0<y<1. The method includes preparing a sulfur-containing organic solution; mixing a zinc-containing precursor and a cadmium-containing precursor with an organic acid, and dissolving them in a co-solvent to obtain a homogeneous solution; and mixing sulfur-containing organic solution with the homogeneous solution to produce Zn1-xCdxA quantum dot.

Abstract: A sulfur species-containing feed gas is processed in a treatment plant in which COS is hydrolyzed, and in which so produced hydrogen sulfide and other sulfur species are absorbed in a lean hydrocarbon liquid. The sulfur species in the so formed rich hydrocarbon liquid are then subjected to catalytic conversion into disulfides, which are subsequently removed from the rich solvent. Most preferably, sulfur free lean solvent is regenerated in a distillation column and/or refinery unit, and light components are recycled from the rich hydrocarbon liquid to the absorber.

Abstract: A semiconductor nanocrystal capable of emitting light with an improved photoluminescence quantum efficiency. The present invention further relates to compositions and devices including semiconductor nanocrystals capable of emitting light with an improved photoluminescence quantum efficiency. A semiconductor nanocrystal wherein the semiconductor nanocrystal is capable of emitting light with a photoluminescence quantum efficiency greater than about 50% upon excitation and including a maximum peak emission with a FWHM less than 20 nm is disclosed. Also disclosed are a device, a population of semiconductor nanocrystals, and a composition including a semiconductor nanocrystal wherein the semiconductor nanocrystal is capable of emitting light with a photoluminescence quantum efficiency greater than about 50% upon excitation and including a maximum peak emission with a FWHM less than 20 nm.

Abstract: Methods for forming colloidal metal chalcogenide nanoparticles generally include forming soluble inorganic metal chalcogen cluster precursors, which are then mixed with a surfactant and heated to form the colloidal metal chalcogenide nanoparticles. The soluble inorganic metal chalcogen cluster precursors are generally formed using a hydrazine-based solvent. The methods can be used with main group and transition metals.

Abstract: Tractable metal oxide sols are made by combining at least one metal oxide compound, at least one organofunctional silane, at least one boron oxide compound, and a liquid, or metal oxide sols are made by combining at least one metal oxide compound, at least one organofunctional silane, at least one of an acid catalyst and salt/complex catalyst, and a liquid. Also disclosed are nanocomposites containing the metal oxide sols and at least one of metal nanoparticle, metal-chalcogenide nanoparticle, metal oxide nanoparticle, and metal phosphate nanoparticle. Further disclosed are composites containing a polymer material and at least one of the metal oxide sol and the nanocomposite.

Abstract: The present invention provides a process for obtaining fullerene-like metal chalcogenide nanoparticles, comprising feeding a metal precursor (INi) selected from metal halide, metal carbonyl, organo-metallic compound and metal oxyhalide vapor into a reaction chamber (12) towards a reaction zone to interact with a flow of at least one chalcogen material (IN2) in gas phase, the temperature conditions in said reaction zone being such to enable the formation of the fullerene-like metal chalcogenide nanoparticles product. The present invention further provides novel IF metal chalcogenides nanoparticles with spherical shape and optionally having a very small or no hollow core and also exhibiting excellent tribological behavior. The present invention further provides an apparatus for preparing various IF nanostructures.

Abstract: The present invention relates to an ultramarine pigment synthesis process which includes a calcination step in the absence of air of a mixture including zeolite A, possibly sodium sulfide and/or sulfur, possibly hydroxide ions, and polysulfides of composition Na2Sn, n being a number greater than 1, the product resulting from the calcination reaction being cooled in the absence of air, leading to obtaining a raw product which includes the synthesized ultramarine pigment, polysulfides and possibly sulfur. The Na2Sn polysulfides taking part in the calcination reaction come at least in part from the recycling of the polysulfides and possibly of the sulfur present in excess in the aforesaid raw product.

Abstract: A process for synthesizing nanostructures is disclosed. The process involves forming a liquid crystalline template by combining a block copolymer, a first reactant in a polar phase, and a nonpolar phase, then contacting the template with a gas phase composed of a second reactant, under conditions effective to form nanostructures.

Abstract: There is provided a process for preparing compounds of formula M3M1A2. The process comprises reacting a compound of formula M2M1A2 with a compound of formula M3X2, in the presence of at least one coordinating solvent. M1 can be chosen from B3+, Al3+, Ga3+, In3+, Tl3+, Fe3+, and Au3+; M2 can be chosen from Li+, Na+, K+, Cs+, (T1)3Si—, and N(T2)4+; M3 can be chosen from Cu+, Ag+, Li+, Na+, K+, Cs+, Rb+, Fr+, Au+, and Hg+; A can be chosen from S and Se; and X2 can be chosen from Cl?, Br?, I?, F?, CH3COO?, NO3?, and CN?. Such compounds can be used for various purposes in the field of electrochemistry.

Abstract: A method for preparing nanowires is disclosed, which comprises the following steps: (a) providing a first precursor solution containing IIB group elements, and a second precursor solution containing VIA group elements; (b) mixing and heating the first precursor solution and the second precursor solution to form a mixed solution; and (c) cooling the mixed solution and filtering the mixed solution to obtain nanowires. The first precursor solution includes compounds of IIB group elements and a surfactant. The second precursor solution includes compounds of VIA group elements. Besides, the surfactant is an organic acid having an aromatic group or a salt thereof.

Abstract: Methods for forming colloidal metal chalcogenide nanoparticles generally include forming soluble inorganic metal chalcogen cluster precursors, which are then mixed with a surfactant and heated to form the colloidal metal chalcogenide nanoparticles. The soluble inorganic metal chalcogen cluster precursors are generally formed using a hydrazine-based solvent. The methods can be used with main group and transition metals.

Abstract: Photo-oxidation catalysts and methods for cleaning a metal-based catalyst are disclosed. An exemplary catalyst system implementing a photo-oxidation catalyst may comprise a metal-based catalyst, and a photo-oxidation catalyst for cleaning the metal-based catalyst in the presence of light. The exposure to light enables the photo-oxidation catalyst to substantially oxidize absorbed contaminants and reduce accumulation of the contaminants on the metal-based catalyst. Applications are also disclosed.

Abstract: In one aspect of this invention, catalytic compositions produced by calcining intermediates of the formula [NR4]x[M12M2S8] are provided, wherein M1 is Mo or W; M2 is Co, Ni, or Pd; x is 2 or 3; and R is a C3-C8 alkyl group. Another aspect provides catalytic compositions produced by calcining intermediates of the formula Ax[M12M2S8], wherein A is selected from K, Rb, Cs, Sr, and Ba. Also provided are methods for making the compositions, and methods of using the compositions for the catalytic conversion of syngas into C1-C4 alcohols such as ethanol.

Abstract: A method is provided for compounding, homogenizing and consolidating compounds. In one embodiment, the charge components are mixed in a controlled addition process, then the newly-formed compound is heated to become totally molten, followed by a rapid quench at room temperature. In an alternate embodiment, the components are supplied with an excess of one component acting as a solvent, heated to dissolve additional components, and then the solvent is separated from the compound to produce homogeneous consolidated compounds. The methods herein are advantageously applied to provide an economical and fast process for producing CdTe, CdZnTe and ZnTe compounds.

Abstract: Disclosed is a method for carrying out a reaction in a microreaction chamber. Nanoparticles which have been advantageously subjected to specific reactions in the microreaction chamber are used for carrying out the reaction. The obtained reaction product, which is preferably also provided in the form of nanoparticles. can then be removed from the microreaction chamber. Advantageously, the ongoing reaction can be specifically influenced by using the microreaction chamber. Both endothermic and exothermic reactions can be carried out with an accurately predictable result by feeding energy in a dosed manner into/out of the reaction chamber.

Abstract: The invention provides a preparation method of Zn1-xCdxA quantum dot capable of emitting white light, in which A is S or S1-ySey; 0<x<1 and 0<y<1. The method includes preparing a sulfur-containing organic solution; mixing a zinc-containing precursor and a cadmium-containing precursor with an organic acid, and dissolving them in a co-solvent to obtain a homogeneous solution; and mixing sulfur-containing organic solution with the homogeneous solution to produce Zn1-xCdxA quantum dot.

Abstract: Methods for forming colloidal metal chalcogenide nanoparticles generally include terming soluble inorganic metal chalcogen cluster precursors, which are then mixed with a surfactant and heated to form the colloidal metal chalcogenide nanoparticles. The soluble inorganic metal chalcogen cluster precursors are generally formed using a hydrazine-based solvent. The methods can be used with main group and transition metals.

Abstract: Soluble chalcogenido clusters together with transition metal ions and main group elements are shown to provide gels having interconnected, open frameworks. Following supercritical drying with liquid carbon dioxide, the chalcogels may be converted to aerogels. The aerogels possess high internal surface areas with a broad pore size distribution that is dependent upon the precursors used and the aging conditions applied. Some of the gels are encompassed by formulas such as M4[M?4Qx]n, M4[M?2Qy]n, M4[M?Qx]n, M3[M?Qx]n, or Me2[M??Qx]n, where M is a divalent, trivalent, or terravalent metal ion; M?, M?, and M?? are typically Ge, Sn, P, As, Sb, Mo, or W; and Q is typically S, Se, or Te. Methods of preparing the chalcogenido clusters are also provided.

Abstract: A method is provided for compounding, homogenizing and consolidating compounds. In one embodiment, the charge components are mixed in a controlled addition process, then the newly-formed compound is heated to become totally molten, followed by a rapid quench at room temperature. In an alternate embodiment, the components are supplied with an excess of one component acting as a solvent, heated to dissolve additional components, and then the solvent is separated from the compound to produce homogeneous consolidated compounds. The methods herein are advantageously applied to provide an economical and fast process for producing CdTe, CdZnTe and ZnTe compounds.

Abstract: Provided are methods for producing pentahalosulfur peroxides and monoxides, such as bis-(pentafluorosulfur) peroxide, that involve exposing a composition comprising a pentahalosulfur hypohalite, and optionally a sulfur hexahalide or trihalomethyl hypohalite, to a halogen free radical scavenger.

Abstract: Conventional optoconductive compounds, such as CIS or CdTe include scarce indium or environmentally-unfriendly cadmium. On the other hand, an optoconductive compound according to the present invention has high optoconductive efficiency without inclusion of indium and cadmium, wherein the optoconductive compound according to the present invention is represented by AXYY? where A is a Group 11 element, X is a Group 15 element, and Y and Y? are Group 16 elements in which Y and Y? can be identical to or different from each other.

Abstract: There is provided a process for preparing compounds of formula M3M1A2. The process comprises reacting a compound of formula M2M1A2 with a compound of formula M3X2, in the presence of at least one coordinating solvent. M1 can be chosen from B3+, Al3+, Ga3+, In3+, Tl3+, Fe3+, and Au3+; M2 can be chosen from Li+, Na+, K+, Cs+, (T1)3Si—, and N(T2)4+; M3 can be chosen from Cu+, Ag+, Li+, Na+, K+, Cs+, Rb+, Fr+, Au+, and Hg+; A can be chosen from S and Se; and X2 can be chosen from Cl?, Br?, I?, F?, CH3COO?, NO3?, and CN?. Such compounds can be used for various purposes in the field of electrochemistry.

Abstract: A method of preparing metal chalcogenides from elemental metal or metal compounds has the following steps: providing at least one elemental metal or metal compound; providing at least one element from periodic table groups 13-15; providing at least one chalcogen; and combining and heating the chalcogen, the group 13-15 element and the metal at sufficient time and temperature to form a metal chalcogenide. A method of functionalizing the surface of semiconducting nanoparticles has the following steps: providing at least one metad compound; providing one chalcogenide having a cation selected from the group 13-15 (B, Al, Ga, In, Si, Ge, Sn, Pb, P, As, Sb and Bi); dissolving the chalcogenide in a first solution; dissolving the metal compound in a second solution; providing and dissolving a functional capping agent in at least one of the solutions of the metal compounds and chalcogenide; combining all solutions; and maintaining the combined solution at a proper temperature for an appropriate time.

Abstract: An alkali metal chalcogenide, particularly K6Sn5Zn4S17, is described as useful in a process for the removal of mercury ions or other metal ions, particularly the selective removal of mercuric or other soft metal ions from water. The resulting metal chalcogenide is new. The invention can be used for the removal of mercury ions from potable water and other metal ion contaminated solutions, or from gaseous fluids.

Abstract: Methods for forming nanoparticles under commercially attractive conditions. The nanoparticles can have very small size and high degree of monodispersity. Low temperature sintering is possible, and highly conductive films can be made. Semiconducting and electroluminescent films can be also made. One embodiment provides a method comprising: (a) providing a first mixture comprising at least one nanoparticle precursor and at least one first solvent for the nanoparticle precursor, wherein the nanoparticle precursor comprises a salt comprising a cation comprising a metal; (b) providing a second mixture comprising at least one reactive moiety reactive for the nanoparticle precursor and at least one second solvent for the reactive moiety, wherein the second solvent phase separates when it is mixed with the first solvent; and (c) combining said first and second mixtures in the presence of a surface stabilizing agent, wherein upon combination the first and second mixtures phase-separate and nanoparticles are formed.

Abstract: A chalcogenide compound synthesis method includes homogeneously mixing solid particles and, during the mixing, imparting kinetic energy to the particle mixture, heating the particle mixture, alloying the elements, and forming alloyed particles containing the compound. Another chalcogenide compound synthesis method includes, under an inert atmosphere, melting the particle mixture in a heating vessel, removing the melt from the heating vessel, placing the melt in a quenching vessel, and solidifying the melt. The solidified melt is reduced to alloyed particles containing the compound. An alloy casting apparatus includes an enclosure, a heating vessel, a flow controller, a collection pan and an actively cooled quench plate. The heating vessel has a bottom-pouring orifice and a pour actuator. The flow controller operates the pour actuator from outside the enclosure. The quench plate is positioned above a bottom of the collection pan and below the bottom-pouring orifice.

Abstract: The present disclosure relates to a nanoparticle containing at least one metal sulfide nanocrystal having a surface modified with a carboxylic acid, wherein the carboxylic acid has at least one aryl group. The present disclosure also describes a method of preparing the nanoparticle, the method consisting of: (a) providing a first solution having a first organic solvent, and a non-alkali metal salt and a carboxylic acid dissolved therein, wherein the carboxylic acid has at least one aryl group; (b) providing a sulfide material; and (c) combining the first solution and the sulfide material to form a reaction solution, thereby forming a nanoparticle containing at least one metal sulfide nanocrystal having a surface modified with the carboxylic acid, wherein the carboxylic acid has at least one aryl group.