A transducer to convert optical energy to electrical energy. The transducer or photo-transducer has a base layer which has a group of connecting elements formed therein at separations which are increasing with the distance away from an emitter layer formed atop the base layer. The connecting elements separate and electrically connect the base layer into base segments, the base segments having increasing thicknesses with the distance away from the emitter layer. The photo-transducer generates an output voltage that is greater than the input light photovoltage. The photo-transducer output voltage is proportional to the number of connecting elements formed in the base layer.

The solar cell structure according to the present invention comprises a nanowire (205) that constitutes the light absorbing part of the solar cell structure and a passivating shell (209) that encloses at least a portion of the nanowire (205). In a first aspect of the invention, the passivating shell (209) of comprises a light guiding shell (210), which preferably has a high- and indirect bandgap to provide light guiding properties. In a second aspect of the invention, the solar cell structure comprises a plurality of nanowires which are positioned with a maximum spacing between adjacent nanowires which is shorter than the wavelength of the light which the solar cell structure is intended to absorbing order to provide an effective medium for light absorption. Thanks to the invention it is possible to provide high efficiency solar cell structures.

A photovoltaic device comprises at least two sub-cells, at least one connecting element electrically connecting adjacent sub-cells to one another, each sub-cell comprising: at least one segment; and at least one connecting element electrically connecting adjacent segments to one another in the event that a sub-cell has more than one segment; each one of the sub-cells having a unique bandgap and being arranged such that bandgaps of the sub-cells are in descending order with respect to a light incident surface of the photovoltaic device, each sub-cell being designed such that all segments of the photovoltaic device produce approximately the same current.

Systems and methods for advanced ultra-high-performance InP solar cells are provided. In one embodiment, an InP photovoltaic device comprises: a p-n junction absorber layer comprising at least one InP layer; a front surface confinement layer; and a back surface confinement layer; wherein either the front surface confinement layer or the back surface confinement layer forms part of a High-Low (HL) doping architecture; and wherein either the front surface confinement layer or the back surface confinement layer forms part of a heterointerface system architecture.

A multijunction solar cell assembly of two or more spatially split solar cell subassemblies, each of which includes a respective monolithic semiconductor body composed of a tandem stack of solar subcells, where the subassemblies are interconnected electrically to one another so that a series electrical circuit is formed between groups of one or more subcells in each subassembly. In some cases, relatively high band gap semiconductor materials can be used for the upper subcells. The solar cell assemblies can be particularly advantageous for applications in space.

A photovoltaic device, particularly a solar cell, comprises an interface between a layer of Group III-V material and a layer of Group IV material with a thin silicon diffusion barrier provided at or near the interface. The silicon barrier controls the diffusion of Group V atoms into the Group IV material, which is doped n-type thereby. The n-type doped region can provide the p-n junction of a solar cell in the Group IV material with superior solar cell properties. It can also provide a tunnel diode in contact with a p-type region of the III-V material, which tunnel diode is also useful in solar cells.

The disclosure describes multi-junction solar cell structures that include two or more graded interlayers.

An alloy composition for a subcell of a solar cell is provided that has a bandgap of at least 0.9 eV, namely, Ga.sub.1-xIn.sub.xN.sub.yAs.sub.1-y-zSb.sub.z with a low antimony (Sb) content and with enhanced indium (In) content and enhanced nitrogen (N) content, achieving substantial lattice matching to GaAs and Ge substrates and providing both high short circuit currents and high open circuit voltages in GaInNAsSb subcells for multijunction solar cells. The composition ranges for Ga.sub.1-xIn.sub.xN.sub.yAs.sub.1-y-zSb.sub.z are 0.07x0.18, 0.025y0.04 and 0.001z0.03.

The disclosure describes multi-junction solar cell structures that include two or more graded interlayers.

A multijunction solar cell and its method of manufacture including interconnected first and second discrete semiconductor regions disposed adjacent and parallel to each other in a single semiconductor body, including first top subcell, second (and possibly third) lattice matched middle subcells; a graded interlayer adjacent to the last middle solar subcell; and a bottom solar subcell adjacent to said graded interlayer being lattice mismatched with respect to the last middle solar subcell; wherein the interconnected regions form at least a four junction solar cell by a series connection being formed between the bottom solar subcell in the first semiconductor region and the bottom solar subcell in the second semiconductor region.