A beyond near-infrared response in a wide-bandgap ZnO/ZnSe coaxial nanowire solar cell by pseudomorphic layers

Wide-bandgap semiconductors are potential materials for photovoltaic (PV) devices in solution-based applications because of their higher stability compared with narrow-bandgap semiconductors. However, these materials are poor absorbers of photons in the solar spectrum and yield modest conversion efficiencies. Here we show how this problem can be solved by the growth and control of pseudomorphic crystals in type-II wide-bandgap ZnO/ZnSe coaxial nanowires. Light absorption of coaxial nanowires under critical strains significantly extended beyond the near-infrared region to cover up to 94% of the solar power. The photocurrent response of the nanowire solar cell was markedly enhanced in visible and infrared regions with a threshold of approximately 0.9 eV, accounting for more than 35% of the conversion efficiency. This work paves the way for stable and efficient PV devices based on wide-bandgap semiconductors.