A multijunction solar cell and its method of fabrication, including an upper and a lower solar subcell each having an emitter layer and a base layer forming a photoelectric junction; a near infrared (NIR) wideband reflector layer disposed below the upper subcell and above the lower subcell for reflecting light in the spectral range of 900 to 1050 nm which represents unused and undesired solar energy and thereby reducing the overall solar energy absorptance in the solar cell and providing thermodynamic radiative cooling of the solar cell when deployed in space outside the atmosphere.

A monolithic metamorphic multi-junction solar cell comprising a first III-V subcell and a second III-V subcell and a third III-V subcell and a fourth Ge subcell, wherein the subcells are stacked on top of each other in the indicated order, and the first subcell forms the topmost subcell, and a metamorphic buffer is formed between the third subcell and the fourth subcell and all subcells each have an n-doped emitter layer and a p-doped base layer, and the emitter layer of the second subcell is greater than the base layer.

A multijunction solar cell including a growth substrate; a graded interlayer disposed over the growth substrate, a plurality of subcells disposed over the graded interlayer including a second solar subcell disposed over and lattice mismatched with respect to the growth substrate, and at least a third solar subcell disposed over the second subcell; the grading interlayer including a plurality of N step-graded sublayers (where N is an integer and the value of N is 1<N<10), wherein each successive sublayer has an incrementally greater lattice constant than the sublayer below it and grown in such a manner that each sublayer is fully relaxed, a distributed Bragg reflector (DBR) layer over the grading interlayer and an upper solar subcell disposed over the third solar subcell, a band gap in the range of 1.95 to 2.20 eV, and composed of a semiconductor compound including at least indium, aluminum and phosphorus.

A space-based solar power station, a power generating satellite module and/or a method for collecting solar radiation and transmitting power generated using electrical current produced therefrom is provided. Each solar power station includes a plurality of satellite modules. The plurality of satellite modules each include a plurality of modular power generation tiles including a photovoltaic solar radiation collector, a power transmitter and associated control electronics. Numerous embodiments relate to efficient power generation tiles. In one embodiment, an efficient power generation tile includes: at least one photovoltaic material; and at least one concentrator that redirects incident solar radiation towards a photovoltaic material such that the photovoltaic material experiences a greater solar flux relative to the case where the photovoltaic material experiences unaltered solar radiation.

A space-based solar power station, a power generating satellite module and/or a method for collecting solar radiation and transmitting power generated using electrical current produced therefrom is provided. Each solar power station includes a plurality of satellite modules. The plurality of satellite modules each include a plurality of modular power generation tiles including a photovoltaic solar radiation collector, a power transmitter and associated control electronics. Numerous embodiments relate to efficient power generation tiles. In one embodiment, an efficient power generation tile includes: at least one photovoltaic material; and at least one concentrator that redirects incident solar radiation towards a photovoltaic material such that the photovoltaic material experiences a greater solar flux relative to the case where the photovoltaic material experiences unaltered solar radiation.

Photovoltaics configured to be manufactured without epitaxial processes and methods for such manufacture are provided. Methods utilize bulk semiconducting crystal substrates, such as, for example, GaAs and InP such that epitaxy processes are not required. Nanowire etch and exfoliation processes are used allowing the manufacture of large numbers of photovoltaic cells per substrate wafer (e.g., greater than 100). Photovoltaic cells incorporate electron and hole selective contacts such that epitaxial heterojunctions are avoided during manufacture.

A photoelectrode, methods of making and using, including systems for water-splitting are provided. The photoelectrode can be a semiconducting material having a photocatalyst such as nickel or nickel-molybdenum coated on the material. The photoelectrode includes an elongated axially integrated wire having at least two different wire compositions.

A photoelectrode, methods of making and using, including systems for water-splitting are provided. The photoelectrode can be a semiconducting material having a photocatalyst such as nickel or nickel-molybdenum coated on the material. The photoelectrode includes an elongated axially integrated wire having at least two different wire compositions.

A solar cell comprising an epitaxial sequence of layers of semiconductor material thrilling at least a first and second solar subcells; a semiconductor contact layer disposed on the bottom surface of the second solar subcell; a reflective metal layer disposed below the semiconductor contact layer such that the reflectivity of the reflective metal layer is greater than 80% in the wavelength range 850 to 2000 nm, for reflecting light back into the second solar subcell.

A solar cell comprising an epitaxial sequence of layers of semiconductor material thrilling at least a first and second solar subcells; a semiconductor contact layer disposed on the bottom surface of the second solar subcell; a reflective metal layer disposed below the semiconductor contact layer such that the reflectivity of the reflective metal layer is greater than 80% in the wavelength range 850 to 2000 nm, for reflecting light back into the second solar subcell.