Unbiased Sunlight Driven Artificial Photosynthesis of Carbon Monoxide from CO2 Using a ZnTe Based Photocathode and a Perovskite Solar Cell in Tandem.
Solar fuel production, mimicking natural photosynthesis of converting CO2 into useful fuels and storing solar energy as chemical energy, has received great attention in recent years. Practical large scale fuel production needs a unique device capable of CO2 reduction using only solar energy and water as an electron source. Here we report such a system composed of a gold decorated triple layered ZnO@ZnTe@CdTe core shell nanorod array photocathode and a CH3NH3PbI3 perovskite solar cell in tandem. The assembly allows effective light harvesting of higher energy photons >2.14 eV) from the front side photocathode and lower energy photons >1.5 eV) from the back side positioned perovskite solar cell in a single photon excitation. This system represents an example of a photocathode photovoltaic tandem device operating under sunlight without external bias for selective CO2 conversion. It exhibited a steady solar to CO conversion efficiency over 0.35% and a solar to fuel conversion efficiency exceeding 0.43% including H2 as a minor product.
ACS nano