There is provided a multi junction photovoltaic device comprising a first sub-cell comprising a photoactive region comprising a layer of perovskite material, a second sub-cell comprising a photoactive silicon absorber. and an intermediate region disposed between and connecting the first sub-cell and the second sub-cell. The intermediate region comprises an interconnect layer, the interconnect layer comprising a two-phase material comprising elongate (i.e. filament like) silicon nanocrystals embedded in a silicon oxide matrix.

A multijunction solar cell including a substrate and a top (or light-facing) solar subcell having an emitter layer, a base layer, and a window layer adjacent to the emitter layer, the window layer composed of a material that is optically transparent, has a band gap of greater than 2.6 eV, and includes an appropriately arranged multilayer antireflection coating on the top surface thereof.

A multijunction solar cell including a substrate and a top (or light-facing) solar subcell having an emitter layer, a base layer, and a window layer adjacent to the emitter layer, the window layer composed of a material that is optically transparent, has a band gap of greater than 2.6 eV, and includes an appropriately arranged multilayer antireflection coating on the top surface thereof.

A tandem solar cell includes a perovskite solar cell including a perovskite absorption layer, a silicon solar cell placed under the perovskite solar cell, a junction layer placed between the perovskite solar cell and the silicon solar cell, an upper electrode placed on the perovskite solar cell, and a lower electrode placed under the silicon solar cell.

A tandem solar cell includes a perovskite solar cell including a perovskite absorption layer, a silicon solar cell placed under the perovskite solar cell, a junction layer placed between the perovskite solar cell and the silicon solar cell, an upper electrode placed on the perovskite solar cell, and a lower electrode placed under the silicon solar cell.

Systems and methods are provided for wirelessly transferring power to a multi junction photovoltaic cell of a space apparatus via a light emission system. The light emission system uses multiple lasers emitting different wavelengths and/or photon energies to produce electron-hole pairs in each layer of the multi junction photovoltaic cell to prompt power generation by the multi junction photovoltaic cell. The light emission system may be located on Earth or on another space apparatus. The multi junction photovoltaic cell can convert sunlight and the light emitted by the light emission system into electrical energy.

Systems and methods are provided for wirelessly transferring power to a multi junction photovoltaic cell of a space apparatus via a light emission system. The light emission system uses multiple lasers emitting different wavelengths and/or photon energies to produce electron-hole pairs in each layer of the multi junction photovoltaic cell to prompt power generation by the multi junction photovoltaic cell. The light emission system may be located on Earth or on another space apparatus. The multi junction photovoltaic cell can convert sunlight and the light emitted by the light emission system into electrical energy.

A solar cell of an embodiment includes a p-electrode, an n-electrode, a p-type light-absorbing layer located between the p-electrode and the n-electrode and mainly containing a cuprous oxide, and an n-type layer that includes a first n-type layer which is located between the p-type light-absorbing layer and the n-electrode, which mainly contains a compound represented by Ga.sub.v1Zn.sub.v2Sn.sub.v3M1.sub.v4O.sub.v5, the M1 being one or more selected from the group consisting of Hf, Zr, In, Ti, Al, B, Mg, Si, and Ge, the v1, the v2, and the v4 being numerical values of 0.00 or more, the v3 and the v5 being numerical values of more than 0, at least one of the v1 and the v2 being a numerical value of more than 0, and the v5 when a sum of the v1, the v2, the v3, and the v4 is 1 being 1.00 or more and 2.00 or less, and which is located on the n-electrode side, and a second n-type layer which is a layer that mainly contains a compound represented by Ga.sub.w1M2.sub.w2M3.sub.w3M4.sub.w4O.sub.w5, the M2 being Al or/and B, the M3 is one or more selected from the group consisting of In, Ti, Zn, Hf, and Zr, the M4 being one or more selected from the group consisting of Sn, Si, and Ge, the w1 and the w5 being numerical values of more than 0, the w2, the w3, and the w4 being numerical values of 0.00 or more, and the w5 when a sum of the w1, the w2, the w3, and the w4 is 2 being 3.00 or more and 3.80 or less, and which is located on the p-type light-absorbing layer side.

A multijunction solar cell including an upper first solar subcell having a first band gap and positioned for receiving an incoming light beam; and a second solar subcell disposed below and adjacent to and lattice matched with said upper first solar subcell, and having a second band gap smaller than said first band gap; wherein at least one of the solar subcells has a graded band gap throughout the thickness of at least a portion of its emitter layer and base layer.

A multijunction solar cell including an upper first solar subcell having a first band gap and positioned for receiving an incoming light beam; and a second solar subcell disposed below and adjacent to and lattice matched with said upper first solar subcell, and having a second band gap smaller than said first band gap; wherein at least one of the solar subcells has a graded band gap throughout the thickness of at least a portion of its emitter layer and base layer.