Abstract: A reservoir for one or more chemical reactants has means for heating the reactants and optional means for stirring the reactants. A pumped reactant feed line and a return line provide fluid communication between the reservoir and a 4-way valve system. The 4-way valve system is also in fluid communication with a reactor vessel and a source of inert gas for purging the system. In a first state, the 4-way valve provides fluid communication between the reservoir and the reactor. In a second state, the 4-way valve provides a continuous circulation path for the heated reactants from the reservoir, to the valve system, and back to the reservoir via the return line. In a third state, the 4-way valve provides a fluid pathway for purging the reactor with inert gas. In a fourth state, the 4-way valve provides a fluid pathway for purging the reservoir with inert gas.

Abstract: Embodiments of the present invention relate to a formulation for use in the fabrication of a light-emitting device, the formulation including a population of semiconductor nanoparticles incorporated into a plurality of discrete microbeads comprising an optically transparent medium, the nanoparticle-containing medium being embedded in a host light-emitting diode encapsulation medium. A method of preparing such a formulation is described. There is further provided a light-emitting device including a primary light source in optical communication with such a formulation and a method of fabricating the same.

Abstract: The present invention relates to a primary particle comprised of a primary matrix material containing a population of semiconductor nanoparticles, wherein each primary particle further comprises an additive to enhance the physical, chemical and/or photo-stability of the semiconductor nanoparticles. A method of preparing such particles is described. Composite materials and light emitting devices incorporating such primary particles are also described.

Abstract: The addition of a chain transfer agent (CTA) or a reversible-addition fragmentation chain transfer agent (RAFT CTA) such as (2-(dodecyl-thiocarbonothioylthio)-2-methylpropionic acid) during the formation of quantum dot polymer films yields films characterized by high and stable quantum yields.

Abstract: Compositions for solution-based deposition of CIGS films are described. The compositions include ternary, quaternary or quinary chalcogenide nanoparticles (i.e., CIGS nanoparticles) and one or more inorganic salts dissolved or dispersed in a solvent to form an ink. The ink can be deposited on a substrate by conventional coating techniques and then annealed to form a crystalline layer. Further processing can be employed to fabricate a PV device. The inorganic salts are included to (i) tune the stoichiometry of the CIGS precursor ink to a desirable ratio, thus tuning the semiconductor band gap, to (ii) dope the CIGS layer with additives, such as Sb and/or Na, to promote grain growth, and/or to (iii) modify and improve the coating properties of the CIGS precursor ink.

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 for formulating a CIGS nanoparticle-based ink, which can be processed to form a thin film with a crack-free limit (CFL) of 500 nm or greater, comprises: dissolving or dispersing Cu(In,Ga)S2 and Cu(In,Ga)Se2 nanoparticles; mixing the nanoparticle solutions/dispersions and adding oleic acid to form an ink; depositing the ink on a substrate; annealing to remove the organic components of the ink formulation; forming a film with a CFL ?500 nm; and, repeating the deposition and annealing process to form a CIGS film having a thickness ?1 ?m. The film so produced may be incorporated into a thin film photovoltaic device.

Abstract: Quantum dot semiconductor nanoparticle compositions that incorporate ions such as zinc, aluminum, calcium, or magnesium into the quantum dot core have been found to be more stable to Ostwald ripening. A core-shell quantum dot may have a core of a semiconductor material that includes indium, magnesium, and phosphorus ions. Ions such as zinc, calcium, and/or aluminum may be included in addition to, or in place of, magnesium. The core may further include other ions, such as selenium, and/or sulfur. The core may be coated with one (or more) shells of semiconductor material. Example shell semiconductor materials include semiconductors containing zinc, sulfur, selenium, iron and/or oxygen ions.

Abstract: Surface-modified nanoparticles are produced by associating ligand interactive agents with the surface of a nanoparticle. The ligand interactive agents are bound to surface modifying ligands that are tailored to impart particular solubility and/or compatibility properties. The ligand interactive agents are crosslinked via a linking/crosslinking agent, such as hexamethoxymethylmelamine or a derivative thereof. The linking/crosslinking agent may provide a binding site for binding the surface modifying ligands to the ligand interactive agents.

Abstract: Multi-phase polymer films of quantum dots (QDs) and their use in light emitting devices (LEDs) are disclosed. The QDs are absorbed in a host matrix, which dispersed within an outer polymer phase. The host matrix is hydrophobic and is compatible with the surface of the QDs. The host matrix may also include a scaffolding material that prevents the QDs from agglomerating. The outer polymer is typically more hydrophilic and prevents oxygen from contacting the QDs.

Abstract: Quantum dots (QDs) are encapsulated within microbeads having a silyl surface shell. The microbeads are prepared by copolymerizing unsaturated resins and an unsaturated organosilane in the presence of QDs. During the copolymerization, the unsaturated resin and the organosilane phase separate, forming beads having a silyl surface shell surrounding an essentially unsilylated interior. The QDs are encapsulated within the interior. The silyl shell provides a barrier against oxygen and other contaminants diffusing into the bead and reacting with the QDs.

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: Multi-phase polymer films of quantum dots (QDs) are disclosed. The QDs are absorbed in a host matrix, which dispersed within an outer polymer phase. The host matrix is hydrophobic and is compatible with the surface of the QDs. The host matrix may also include a scaffolding material that prevents the QDs from agglomerating. The outer polymer is typically more hydrophilic and prevents oxygen from contacting the QDs.

Abstract: Certain dithio-compounds have been found to be superior capping ligands for quantum dot (QD) nanoparticles. Example dithio-ligands include dithiocarbamate ligands. These strongly binding ligands are capable of coordinating to both positive and negative atoms on the surface of the nanoparticle. The ligands are bi-dentate and thus their approach to the QD surface is not as sterically hindered as is the approach of mono-dentate ligands. These ligands can therefore completely saturate the QD surface.

Abstract: Quantum dots used to modify the spectral output of an LED exhibit less of a performance decrease (due to increased temperature) when incorporated in a chip on board (COB) as compared to conventional LED packages. A ceramic ring may be used to shield the quantum dots from the heat associated with connecting electrical leads to pads on the COB. The upper surface of the ceramic ring may be sealed with a glass disk or other transparent material.

Abstract: Light-emitting materials are made from a porous light-emitting semiconductor having quantum dots (QDs) disposed within the pores. According to some embodiments, the QDs have diameters that are essentially equal in size to the width of the pores. The QDs are formed in the pores by exposing the porous semiconductor to gaseous QD precursor compounds, which react within the pores to yield QDs. According to certain embodiments, the pore size limits the size of the QDs produced by the gas-phase reactions. The QDs absorb light emitted by the light-emitting semiconductor material and reemit light at a longer wavelength than the absorbed light, thereby “down-converting” light from the semiconductor material.

Abstract: A method of producing nanoparticles comprises effecting conversion of a nanoparticle precursor composition to the material of the nanoparticles. The precursor composition comprises a first precursor species containing a first ion to be incorporated into the growing nanoparticles and a separate second precursor species containing a second ion to be incorporated into the growing nanoparticles. The conversion is effected in the presence of a molecular cluster compound under conditions permitting seeding and growth of the nanoparticles.

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: The present invention relates to a primary particle comprised of a primary matrix material containing a population of semiconductor nanoparticles, wherein each primary particle further comprises an additive to enhance the physical, chemical and/or photo-stability of the semiconductor nanoparticles. A method of preparing such particles is described. Composite materials and light emitting devices incorporating such primary particles are also described.

Abstract: A scalable method for the manufacture of narrow, bright, monodisperse, photo-luminescent quantum dots prepared in the presence of a Group II-VI molecular seeding cluster fabricated in situ from a zinc salt and a thiol or selenol compound. Exemplary quantum dots have a core containing indium, phosphorus, zinc and either sulfur or selenium.