| 摘要 |
A photovoltaic device comprises an upper cell and a lower cell separated by an electrically insulating layer. The cells and the layers are fabricated as a single monolithic structure, and separate electrical contacts are provided for the upper and lower cells to allow independent extraction of current from each cell. The upper cell has a larger bandgap than the lower cell so that incident low energy photons unabsorbed and unconverted by the upper cell can propagate through to the lower cell for conversion. The two bandgaps can be selected to accommodate spectral' ranges of interest. The device is incorporated into a system including two sources of photons with different wavelength ranges associated with the bandgaps of the two cells, such that each cell can convert photons from one source. One source may be the sun and the other may be a local photon source such as a thermal source. Alternatively, both photon sources may be local sources. Operation of the device can be further optimised and extended by configuring the upper cell as a tandem cell or in a MIMS arrangement, or both. |
