Light-emitting quantum dot films, quantum dot lighting devices, and quantum dot-based backlight units are provided. Related compositions, components, and methods are also described. Improved quantum dot encapsulation and matrix materials are provided. Quantum dot films with protective barriers are described. High-efficiency, high brightness, and high-color purity quantum dot-based lighting devices are also included, as well as methods for improving efficiency and optical characteristics in quantum dot-based lighting devices.

Highly luminescent nanostructures, particularly highly luminescent quantum dots, comprising a nanocrystal core and thick shells of ZnSe and ZnS, are provided. The nanostructures may have one or more gradient ZnSe.sub.xS.sub.1-x monolayers between the ZnSe and ZnS shells, wherein the value of x decreases gradually from the interior to the exterior of the nanostructure. Also provided are methods of preparing the nanostructures comprising a high temperature synthesis method. The thick shell nanostructures of the present invention display increased stability and are able to maintain high levels of photoluminescent intensity over long periods of time. Also provided are nanostructures with increased blue light absorption.

Disclosed herein is a quantum dot composite that can maintain luminous efficiency per unit quantum dot even when a quantum dot concentration is high, and therefore can achieve a high emission intensity. The quantum dot composite includes: a matrix; and quantum dots dispersed in the matrix, wherein the matrix is composed of cellulose acetate having a compositional distribution index (CDI) of 3.0 or less, and a concentration of the quantum dots is 0.05 wt % or higher.

Highly luminescent nanostructures, particularly highly luminescent quantum dots, comprising a nanocrystal core are provided. Also provided are methods of increasing the sphericity of nanostructures comprising subjecting nanocrystal cores to an acid etch step, an annealing step, or a combination of an acid etch step and an annealing step.

An optical device comprising: a quantum dot, said quantum dot comprising InAs and adapted to emit radiation in the wavelength range from 1200 nm to 2000 nm; a supporting layer supporting said quantum dot, said supporting layer being lattice matched to InP; and wherein the longest dimension of the base of the quantum dot provided parallel to the supporting layer is within 20% of the shortest dimension of the base provided parallel to the supporting layer.

A nanocrystal capable of light emission includes a nanoparticle having photoluminescence having quantum yields of greater than 30%.

Composites having semiconductor structures embedded in a matrix are described. In an example, a composite includes a matrix material. A plurality of semiconductor structures is embedded in the matrix material. Each semiconductor structure includes an anisotropic nanocrystalline core composed of a first semiconductor material. Each semiconductor structure also includes a nanocrystalline shell composed of a second, different, semiconductor material at least partially surrounding the anisotropic nanocrystalline core. An insulator layer encapsulates each nanocrystalline shell and anisotropic nanocrystalline core pairing.

A color conversion film includes a substrate, a number of first and second indentations defined in the substrate, and a number of quantum dot blocks received in the first and second indentations. The substrate includes a first surface and a second surface parallel to the first surface. The first indentations are defined in the first surface and extended towards an interior of the substrate. The second indentations are defined in the second surface and extended towards an interior of the substrate. The quantum dot blocks converts an incident light to a light with a specific color.

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

A silicon-based quantum dot device (1) is disclosed. The device comprises a substrate (8) and a layer (7) of silicon or silicon-germanium supported on the substrate which is configured to provide at least one quantum dot (5.sub.1, 5.sub.2: FIG. 5). The layer of silicon or silicon-germanium has a thickness of no more than ten monolayers. The layer of silicon or silicon-germanium may have a thickness of no more than eight or five monolayers.