Abstract: A core/shell semiconductor nanoparticle structure comprises a core comprising a halide perovskite semiconductor and a shell comprising a semiconductor material that is not a halide perovskite (and that is substantially free of halide perovskites). The halide perovskite semiconductor core may be of the form AMX3, wherein: A is an organic ammonium such as CH3NH3+, (C8H17)2(CH3NH3)+, PhC2H4NH3+, C6H11CH2NH3+ or 1-adamantyl methyl ammonium, an amidinium such as CH(NH2)2+, or an alkali metal cation such as Li+, Na+, K+, Rb+ or Cs+; M is a divalent metal cation such as Mg2+, Mn2+, Ni2+, Co2+, Pb2+, Sn2+, Zn2+, Ge2+, Eu2+, Cu2+ or Cd2+; and X is a halide anion (F?, Cl?, Br?, I?) or a combination of halide anions.

Abstract: Materials and methods for preparing Cu2XSnY4 nanoparticles, wherein X is Zn, Cd, Hg, Ni, Co, Mn or Fe and Y is S or Se, (CXTY) are disclosed herein. The nanoparticles can be used to make layers for use in thin film photovoltaic (PV) cells. The CXTY materials are prepared by a colloidal synthesis in the presence of labile organo-chalcogens. The organo-chalcogens serves as both a chalcogen source for the nanoparticles and as a capping ligand for the nanoparticles.

Abstract: Materials and methods for preparing Cu2XSnY4 nanoparticles, wherein X is Zn, Cd, Hg, Ni, Co, Mn or Fe and Y is S or Se, (CXTY) are disclosed herein. The nanoparticles can be used to make layers for use in thin film photovoltaic (PV) cells. The CXTY materials are prepared by a colloidal synthesis in the presence of labile organo-chalcogens. The organo-chalcogens serves as both a chalcogen source for the nanoparticles and as a capping ligand for the nanoparticles.

Abstract: Materials and methods for preparing Cu2XSnY4 nanoparticles, wherein X is Zn, Cd, Hg, Ni, Co, Mn or Fe and Y is S or Se, (CXTY) are disclosed herein. The nanoparticles can be used to make layers for use in thin film photovoltaic (PV) cells. The CXTY materials are prepared by a colloidal synthesis in the presence of labile organo-chalcogens. The organo-chalcogens serves as both a chalcogen source for the nanoparticles and as a capping ligand for the nanoparticles.

Abstract: Materials and methods for preparing Cu2XSnY4 nanoparticles, wherein X is Zn, Cd, Hg, Ni, Co, Mn or Fe and Y is S or Se, (CXTY) are disclosed herein. The nanoparticles can be used to make layers for use in thin film photovoltaic (PV) cells. The CXTY materials are prepared by a colloidal synthesis in the presence of labile organo-chalcogens. The organo-chalcogens serves as both a chalcogen source for the nanoparticles and as a capping ligand for the nanoparticles.

Abstract: Various methods are used to provide a desired doping metal concentration in a CIGS-containing ink when the CIGS layer is deposited on a photovoltaic device. When the doping metal is sodium, it may be incorporated by: adding a sodium salt, for example sodium acetate, together with the copper-, indium- and/or gallium-containing reagents at the beginning of the synthesis reaction of Cu(In,Ga)(S,Se)2 nanoparticles; synthesizing Cu(In,Ga)(S,Se)2 nanoparticles and adding a sodium salt to the reaction solution followed by mild heating before isolating the nanoparticles to aid sodium diffusion; and/or, using a ligand that is capable of capping the Cu(In,Ga)(S,Se)2 nanoparticles with one end of its molecular chain and binding to sodium atoms with the other end of its chain.

Abstract: Various methods are used to provide a desired doping metal concentration in a CIGS-containing ink when the CIGS layer is deposited on a photovoltaic device. When the doping metal is antimony, it may be incorporated by: adding an antimony salt together with copper-, indium- and/or gallium-containing reagents at the beginning of the synthesis reaction of Cu(In,Ga)(S,Se)2 nanoparticles; synthesizing Cu(In,Ga)(S,Se)2 nanoparticles and adding an antimony salt to the reaction solution followed by mild heating before isolating the nanoparticles to aid antimony diffusion; and/or, using a ligand that is capable of capping the Cu(In,Ga)(S,Se)2 nanoparticles with one end of its molecular chain and binding to antimony atoms with the other end of its chain.

Abstract: A method for the preparation of copper indium gallium diselenide/disulfide (CIGS) nanoparticles utilizes a copper-rich stoichiometry. The copper-rich CIGS nanoparticles are capped with organo-chalcogen ligands, rendering the nanoparticles processable in organic solvents. The nanoparticles may be deposited on a substrate and thermally processed in a chalcogen-rich atmosphere to facilitate conversion of the excess copper to copper selenide or copper sulfide that may act as a sintering flux to promote liquid phase sintering and thus the growth of large grains. The nanoparticles so produced may be used to fabricate CIGS-based photovoltaic devices.

Abstract: A method of synthesis of two-dimensional metal chalcogenide monolayers, such as WSe2 and MoSe2, is based on a chemical vapor deposition approach that uses H2Se or alkyl or aryl selenide precursors to form a reactive gas. The gaseous selenium precursor may be introduced into a tube furnace containing a metal precursor at a selected temperature, wherein the selenium and metal precursors react to form metal chalcogenide monolayers.

Abstract: A method of synthesis of two-dimensional (2D) nanoflakes comprises the cutting of prefabricated nanoparticles. The method allows high control over the shape, size and composition of the 2D nanoflakes, and can be used to produce material with uniform properties in large quantities. Van der Waals heterostructure devices are prepared by fabricating nanoparticles, chemically cutting the nanoparticles to form nanoflakes, dispersing the nanoflakes in a solvent to form an ink, and depositing the ink to form a thin film.

Abstract: A method for the preparation of copper indium gallium diselenide/disulfide (CIGS) nanoparticles utilizes a copper-rich stoichiometry. The copper-rich CIGS nanoparticles are capped with organo-chalcogen ligands, rendering the nanoparticles processable in organic solvents. The nanoparticles may be deposited on a substrate and thermally processed in a chalcogen-rich atmosphere to facilitate conversion of the excess copper to copper selenide or copper sulfide that may act as a sintering flux to promote liquid phase sintering and thus the growth of large grains. The nanoparticles so produced may be used to fabricate CIGS-based photovoltaic devices.

Abstract: A core/shell semiconductor nanoparticle structure comprises a core comprising a halide perovskite semiconductor and a shell comprising a semiconductor material that is not a halide perovskite (and that is substantially free of halide perovskites). The halide perovskite semiconductor core may be of the form AMX3, wherein: A is an organic ammonium such as CH3NH3+, (C8H17)2(CH3NH3)+, PhC2H4NH3+, C6H11CH2NH3+ or 1-adamantyl methyl ammonium, an amidinium such as CH(NH2)2+, or an alkali metal cation such as Li+, Na+, K+, Rb+ or Cs+; M is a divalent metal cation such as Mg2+, Mn2+, Ni2+, Co2+, Pb2+, Sn2+, Zn2+, Ge2+, Eu2+, Cu2+ or Cd2+; and X is a halide anion (F?, Cl?, Br?, I?) or a combination of halide anions.

Abstract: A method of synthesizing two-dimensional (2D) nanoparticles of transition metal dichalcogenide (TMDC) material utilises a molecular cluster compound. The method allows a high degree of control over the shape, size and composition of the 2D TMDC nanoparticles, and may be used to produce material with uniform properties in large quantities.

Abstract: A method of synthesis of two-dimensional (2D) nanoflakes comprises the cutting of prefabricated nanoparticles. The method allows high control over the shape, size and composition of the 2D nanoflakes, and can be used to produce material with uniform properties in large quantities. Van der Waals heterostructure devices are prepared by fabricating nanoparticles, chemically cutting the nanoparticles to form nanoflakes, dispersing the nanoflakes in a solvent to form an ink, and depositing the ink to form a thin film.

Abstract: A method of synthesis of two-dimensional metal chalcogenide monolayers, such as WSe2 and MoSe2, is based on a chemical vapor deposition approach that uses H2Se or alkyl or aryl selenide precursors to form a reactive gas. The gaseous selenium precursor may be introduced into a tube furnace containing a metal precursor at a selected temperature, wherein the selenium and metal precursors react to form metal chalcogenide monolayers.

Abstract: A method of preparing Group XIII selenide nanoparticles comprises reacting a Group XIII ion source with a selenol compound. The nanoparticles have an MxSey Semiconductor core (where M is In or Ga) and an organic capping ligand attached to the core via a carbon-selenium bond. The selenol provides a source of selenium for incorporation into the semiconductor core and also provides the organic capping ligand. The nanoparticles are particularly suitable for solution-based methods of preparing semiconductor films.

Abstract: An illuminated sign has a primary light source in spaced apart relation to a transparent or translucent substrate having quantum dot phosphors printed or coated thereon. The primary light source may be a blue LED, a white LED or an LED having a significant portion of its emission in the ultraviolet region of the spectrum. The LED may be a backlight for the transparent or translucent substrate and/or an edge light, a down light or an up light.

Abstract: Nanoparticles containing IUPAC group 11 ions, group 13 ions and sulfur ions are synthesized by adding metal salts and an alkanethiol in an organic solvent and promoting the reaction by applying heat. Nanoparticles are formed at temperatures as low as 200° C. The nanoparticles may be thermally annealed for a certain amount of time at a temperature lower than the reaction temperature (usually ˜40° C. lower) to improve the topology and narrow the size distribution. After the reaction is complete, the nanoparticles may be isolated by the addition of a non-solvent and re-dispersed in organic solvents including toluene, chloroform and hexane to form a nanoparticle ink. Additives may be incorporated in the reaction solution to tailor the final ink viscosity.

Abstract: A method of preparing Group XIII selenide nanoparticles comprises reacting a Group XIII ion source with a selenol compound. The nanoparticles have an MxSey Semiconductor core (where M is In or Ga) and an organic capping ligand attached to the core via a carbon-selenium bond. The selenol provides a source of selenium for incorporation into the semiconductor core and also provides the organic capping ligand. The nanoparticles are particularly suitable for solution-based methods of preparing semiconductor films.

Abstract: Materials and methods for preparing Cu2XSnY4 nanoparticles, wherein X is Zn, Cd, Hg, Ni, Co, Mn or Fe and Y is S or Se, (CXTY) are disclosed herein. The nanoparticles can be used to make layers for use in thin film photovoltaic (PV) cells. The CXTY materials are prepared by a colloidal synthesis in the presence of labile organo-chalcogens. The organo-chalcogens serves as both a chalcogen source for the nanoparticles and as a capping ligand for the nanoparticles.