Light invariant, efficient, multiple band gap AlGaAs/Si/metal hydride solar cell

Electronic and ionic charge transfer provides a basis for composite semiconductor/electrolyte systems featuring simultaneous solar/electrical conversion and solar energy storage. This cell contains both multiple band gap and electrochemical storage, and provides a nearly constant energetic output in illuminated or dark conditions. Multiple semiconductor band gaps can enhance the energetics of this interaction. The cell combines bipolar AlGaAs ${\mathrm{(E}}_g\text{=1.6}$ eV) and Si ${\mathrm{(E}}_g\text{=1.1}$ eV) and ${\mathrm{AB}}_{\mathrm{5}}$ metal hydride/NiOOH storage, and generates a light variation insensitive potential of 1.2–1.3 V at total (including storage losses) solar/electrical energy conversion efficiency of 18.1%.