68.9% Efficient GaAs-Based Photonic Power Conversion Enabled by Photon Recycling and Optical Resonance. Cover Picture

A thin-film GaAs/AlGaAs rear-heterojunction photonic power converter with a back reflector is presented by Henning Helmers and co-workers in article number 2100113. Photon recycling is leveraged to increase the excess carrier density and consequently the output voltage. Optical resonance yields highest absorptance for near-bandgap photons. Thereby thermalization losses are minimized without compromising minimal transmission. A photovoltaic conversion efficiency of 68.9% for 858 nm monochromatic light is demonstrated.