Abstract:
A semiconductor nanocrystal including a core comprising a first semiconductor material comprising at least three chemical elements and a shell disposed over at least a portion of the core, the shell comprising a second semiconductor material, wherein the semiconductor nanocrystal is capable of emitting light with an improved photoluminescence quantum efficiency. Also disclosed are populations of semiconductor nanocrystals, compositions and devices including a semiconductor nanocrystal capable of emitting light with an improved photoluminescence quantum efficiency. In one embodiment, a semiconductor nanocrystal includes a core comprising a first semiconductor material comprising at least three chemical elements and a shell disposed over at least a portion of the core, the shell comprising a second semiconductor material, wherein the semiconductor nanocrystal is capable of emitting light upon excitation with a photoluminescence quantum efficiency greater than about 65%. In another embodiment, a semiconductor nanocrystal includes a core comprising a first semiconductor material comprising zinc, cadmium, and sulfur and a shell disposed over at least a portion of the core, the shell comprising a second semiconductor material. In a further embodiment, a semiconductor nanocrystal includes a core comprises a first semiconductor material comprising at least three chemical elements and a shell disposed over at least a portion of the core, the shell comprising a second semiconductor material comprising at least three chemical elements, wherein the semiconductor nanocrystal is capable of emitting light with a photoluminescence quantum efficiency greater than about 60% upon excitation. In a further embodiment, a semiconductor nanocrystal including a core comprises a first semiconductor material comprising zinc, cadmium, and selenium and a shell disposed over at least a portion of the core, the shell comprising a second semiconductor material, wherein the semiconductor nanocrystal is capable of emitting light with a photoluminescence quantum efficiency greater than about 60% upon excitation.
Abstract:
A composition comprising a semiconductor nanocrystal including a core comprising a first semiconductor material comprising at least three chemical elements and a shell disposed over at least a portion of the core, the shell comprising a second semiconductor material, wherein the semiconductor nanocrystal is capable of emitting light upon excitation with a photoluminescence quantum efficiency greater than about 65%. Also disclosed is a composition comprising a semiconductor nanocrystal including a core comprising a first semiconductor material comprising at least three chemical elements and a shell disposed over at least a portion of the core, the shell comprising a second semiconductor material comprising at least three chemical elements, wherein the semiconductor nanocrystal is capable of emitting light with a photoluminescence quantum efficiency greater than about 60% upon excitation.
Abstract:
A quantum dot including a fluorine-containing ligand attached to a surface thereof and having a coating comprising a fluoropolymer over at least a portion of the outer surface of the quantum dot. A method for preparing a quantum dot with a coating comprising a fluoropolymer over at least a portion of the outer surface of the quantum dot is also disclosed. The method comprises contacting a quantum dot having a fluorine-containing ligand attached to a surface thereof with a fluoropolymer to coat the fluoropolymer over at least a portion of the outer surface of the quantum dot. A device including the quantum dot taught herein is further disclosed. An emissive material including the quantum dot taught herein is further disclosed.
Abstract:
A population of nanocrystals including a core comprising a first semiconductor material comprising one or more elements of Group IIIA of the Periodic Table of Elements and one or more elements of Group VA of the Periodic Table of Elements, and a shell disposed over at least a portion of the core, the shell comprising a second semiconductor material, wherein the nanocrystal is capable of emitting light having a photoluminescence quantum efficiency of at least about 30% upon excitation. Also disclosed is a nanocrystal comprising a nanocrystal core and a shell comprising a semiconductor material comprising at least three chemical elements and obtainable by a process comprising adding a precursor for at least one of the chemical elements of the semiconductor material from a separate source to a nanocrystal core while simultaneously adding amounts of precursors for the other chemical elements of the semiconductor material. Devices including nanocrystals are disclosed.
Abstract:
A semiconductor nanocrystal capable of emitting blue light upon excitation. Also disclosed are devices, populations of semiconductor nanocrystals, and compositions including a semiconductor nanocrystal capable of emitting blue light upon excitation. In one embodiment, a semiconductor nanocrystal capable of emitting blue light including a maximum peak emission at a wavelength not greater than about 470 nm with a photoluminescence quantum efficiency greater than about 65% upon excitation. In another embodiment, a semiconductor nanocrystal includes a core comprising a first semiconductor material comprising at least three chemical elements and a shell disposed over at least a portion of the core, the shell comprising a second semiconductor material, wherein the semiconductor nanocrystal is capable of emitting blue light with a photoluminescence quantum efficiency greater than about 65% upon excitation. In a further embodiment, a semiconductor nanocrystal includes a core comprising a first semiconductor material comprising at least three chemical elements and a shell disposed over at least a portion of the core, the shell comprising a second semiconductor material comprising at least three chemical elements, wherein the semiconductor nanocrystal is capable of emitting light including a maximum peak emission in the blue region of the spectrum upon excitation.
Abstract:
A population of nanocrystals including a core comprising a first semiconductor material comprising one or more elements of Group IIIA of the Periodic Table of Elements and one or more elements of Group VA of the Periodic Table of Elements, and a shell disposed over at least a portion of the core, the shell comprising a second semiconductor material, wherein the nanocrystal is capable of emitting light having a photoluminescence quantum efficiency of at least about 30% upon excitation. Also disclosed is a nanocrystal comprising a nanocrystal core and a shell comprising a semiconductor material comprising at least three chemical elements and obtainable by a process comprising adding a precursor for at least one of the chemical elements of the semiconductor material from a separate source to a nanocrystal core while simultaneously adding amounts of precursors for the other chemical elements of the semiconductor material. Devices including nanocrystals are disclosed.
Abstract:
A method for making a device, the method comprising: depositing a layer comprising quantum dots over a first electrode, the quantum dots including ligands attached to the outer surfaces thereof; treating the surface of the deposited layer comprising quantum dots to remove the exposed ligands; and forming a device layer thereover. Also disclosed is a device made in accordance with the disclosed method. Another aspect of the invention relates to a device comprising a first electrode and a second electrode, and a layer comprising quantum dots between the two electrodes, the layer comprising quantum dots deposited from a dispersion that have been treated to remove exposed ligands after formation of the layer in the device. Another aspect of the invention relates to a device comprising a first electrode and a second electrode, a layer comprising a first inorganic semiconductor material disposed between the first and second electrodes, and a plurality of quantum dots disposed between the first and second electrodes, the outer surface of the quantum dots comprising a second inorganic semiconductor material, wherein the composition of the first inorganic semiconductor material and the second inorganic semiconductor material is the same (without regard to any ligands on the outer surface of the quantum dot).
Abstract:
A nanocrystal comprising a semiconductor material comprising one or more elements of Group IIIA of the Periodic Table of Elements and one or more elements of Group VA of the Periodic Table of Elements, wherein the nanocrystal is capable of emitting light having a photoluminescence quantum efficiency of at least about 30% upon excitation. Also disclosed is a nanocrystal including a core comprising a first semiconductor material comprising one or more elements of Group IIIA of the Periodic Table of Elements and one or more elements of Group VA of the Periodic Table of Elements, and a shell disposed over at least a portion of the core, the shell comprising a second semiconductor material, wherein the nanocrystal is capable of emitting light having a photoluminescence quantum efficiency of at least about 30% upon excitation. Also disclosed is a nanocrystal comprising a nanocrystal core and a shell comprising a semiconductor material disposed on at least a portion of the nanocrystal core, wherein the semiconductor material comprises at least three chemical elements and is obtainable by a process comprising adding a precursor for at least one of the chemical elements of the semiconductor material from a separate source to a nanocrystal core while simultaneously adding amounts of precursors for the other chemical elements of the semiconductor material. A population of nanocrystals, method for preparing nanocrystals, compositions, and devices including nanocrystals are also disclosed.
Abstract:
A semiconductor nanocrystal capable of emitting blue light upon excitation. Also disclosed are devices, populations of semiconductor nanocrystals, and compositions including a semiconductor nanocrystal capable of emitting blue light upon excitation. In one embodiment, a semiconductor nanocrystal capable of emitting blue light including a maximum peak emission at a wavelength not greater than about 470 nm with a photoluminescence quantum efficiency greater than about 65% upon excitation. In another embodiment, a semiconductor nanocrystal includes a core comprising a first semiconductor material comprising at least three chemical elements and a shell disposed over at least a portion of the core, the shell comprising a second semiconductor material, wherein the semiconductor nanocrystal is capable of emitting blue light with a photoluminescence quantum efficiency greater than about 65% upon excitation. In a further embodiment, a semiconductor nanocrystal includes a core comprising a first semiconductor material comprising at least three chemical elements and a shell disposed over at least a portion of the core, the shell comprising a second semiconductor material comprising at least three chemical elements, wherein the semiconductor nanocrystal is capable of emitting light including a maximum peak emission in the blue region of the spectrum upon excitation.
Abstract:
A nanoparticle including an inorganic core comprising at least one metal and/or at least one semi-conductor compound comprising at least one metal includes a coating or shell disposed over at least a portion of a surface of the core. The coating can include one or more layers. Each layer of the coating can comprise a metal and/or at least one semiconductor compound. The nanoparticle further includes a ligand attached to a surface of the coating. The ligand is represented by the formula: X-Sp-Z, wherein X represents, e.g., a primary amine group, a secondary amine group, a urea, a thiourea, an imidizole group, an amide group, a phosphonic or arsonic acid group, a phosphinic or arsinic acid group, a phosphate or arsenate group, a phosphine or arsine oxide group; Sp represents a spacer group, such as a group capable of allowing a transfer of charge or an insulating group; and Z represents: (i) a reactive group capable of communicating specific chemical properties to the nanocrystal as well as provide specific chemical reactivity to the surface of the nanocrystal, and/or (ii) a group that is cyclic, halogenated, or polar a-protic. In certain embodiments, at least two chemically distinct ligands are attached to an surface of the coating, wherein the at least two ligands (I and II) are represented by the formula: X-Sp-Z. In ligand (I) X represents a phosphonic, phosphinic, or phosphategroup and in ligand (II) X represents a primary or secondary amine, or an imidizole, or an amide; In both ligands (I) and (II) Sp, which can be the same or different in the two compounds, represents a spacer group, such as a group capable of allowing a transfer of charge or an insulating group; Z, which can be the same or different in the two compounds, is a group chosen from among groups capable of communicating specific chemical properties to the nanoparticle as well as provide specific chemical reactivity to the surface of the nanoparticle. In preferred embodiments, the nanoparticle includes a core comprising a semiconductor material.