A composite material for fluorescent quantum dot micro-nano packaging. The composite material comprises fluorescent quantum dots, a mesoporous particle material having a nanometer lattice structure, and a barrier layer, wherein the fluorescent quantum dots are distributed in the mesoporous particle material, and the barrier layer is coated on the outer surface of the mesoporous particle material. In the composite material according to the invention, the quantum dot aggregation can be effectively retarded, with the barrier layer coated on the surface the water-oxygen micromolecule erosion is prevented, the compatibility and stability of the composite fluorescent particles is improved, and the service life of the composite material for fluorescent quantum dot micro-nano packaging is thus greatly improved.

The present invention is based on a unique design of a novel structure, which incorporates two quantum dots of a different bandgap separated by a tunneling barrier. Upconversion is expected to occur by the sequential absorption of two photons. In broad terms, the first photon excites an electron-hole pair via intraband absorption in the lower bandgap dot, leaving a confined hole and a relatively delocalized electron. The second absorbed photon can lead, either directly or indirectly, to further excitation of the hole, enabling it to then cross the barrier layer. This, in turn, is followed by radiative recombination with the delocalized electron.

Various embodiment include optical and optoelectronic devices and methods of making same. Under one aspect, an optical device includes an integrated circuit having an array of conductive regions, and an optically sensitive material over at least a portion of the integrated circuit and in electrical communication with at least one conductive region of the array of conductive regions. Under another aspect, a film includes a network of fused nanocrystals, the nanocrystals having a core and an outer surface, wherein the core of at least a portion of the fused nanocrystals is in direct physical contact and electrical communication with the core of at least one adjacent fused nanocrystal, and wherein the film has substantially no defect states in the regions where the cores of the nanocrystals are fused. Additional devices and methods are described.

A photovoltaic device is fabricated using nanostructured hybrid ferrite materials with interdigital electrodes. The device includes ferrimagnetic ferrite nanopartides having a tunable narrow bandgap of 2.5 eV or less, which are deposited onto a thin ferroelectric film. The device produces an ultrahigh photocurrent density of 13-15 mA/cm.sup.2 when illuminated with sunlight of 100 mW/cm.sup.2, which is comparable to that of organic or silicon-based solar cells.

Solar-redshift systems comprise an integral array of redshift modules, each having at least a focusing device, a target, and a quantum-dot vessel. The quantum-dot vessel contains quantum dots that emit light having an emission wavelength. The focusing device directs incident solar radiation through a focusing gap and toward the quantum-dot vessel, or into a slab waveguide and then toward the quantum-dot vessel, causing the quantum dots to emit redshifted light having the emission wavelength. The redshifted light is directed to the target, examples of which include a photovoltaic material or a living photosynthetic organism. The target has increased sensitivity or response to photons having the wavelength of the redshifted light. A trapping reflector component of the quantum-dot vessel prevents loss of redshifted light to the environment outside the solar-redshift system and allows undesirable infrared light to be removed from the system.

The disclosure provides a multi-junction solar cell structure and the manufacturing method thereof, comprising a first photovoltaic structure and a second photovoltaic structure; wherein at least one of the first photovoltaic structure and the second photovoltaic structure comprises a discontinuous photoelectric converting structure.

A photoelectric conversion element includes a superlattice semiconductor layer including barrier sub-layers and quantum sub-layers (quantum dot sub-layers) alternately stacked and also includes a wavelength conversion layer containing a wavelength conversion material converting the wavelength of incident light. The wavelength conversion layer converts incident light into light with a wavelength corresponding to an optical transition from a quantum level of the conduction band of the superlattice semiconductor layer to a continuum level of the conduction band.

Coated beads made of a primary matrix material and containing a population of quantum dot nanoparticles. Each bead has a multi-layer surface coating. The layers can be two or more distinct surface coating materials. The surface coating materials may be inorganic materials and/or polymeric materials. A method of preparing such particles is also described. The coated beads are useful for composite materials for applications such as light-emitting devices.

A composite quantum-dot photodetector comprising a substrate with a colloidally deposited thin film structure forming a photosensitive region, the thin film containing at least one type of a nanocrystal quantum-dot, whereby the nanocrystal quantum dots are spaced by ligands to form a lattice, and the lattice of the quantum dots has an infill material that forms an inorganic matrix that isolates the nanocrystal quantum dots from atmospheric exposure.

The present application relates to a photodetector based on interband transition in quantum wells. The photodetector may include a first semiconductor layer having a first conduction type; a second semiconductor layer having a second conduction type different from the first conduction type; and a photon absorption layer arranged between the first semiconductor layer and the second semiconductor layer, the photon absorption layer including at least one quantum well layer and barrier layers arranged on both sides of each quantum well layer. The present application utilizes the modulating effect of a semiconductor PN junction on a photoelectric conversion process associated with quantum wells to significantly increase a current output of the photodetector based on the quantum well material.