Single junction CsPbBr₃ solar cell coupled with electrolyzer for solar water splitting

Artificial photosynthesis system to realize Solar overall water splitting has been regarded as sustainable and renewable solution for energy and environmental issues. While artificial photosynthesis system (efficiency of 12.4%) greatly exceeds efficiency of natural photosynthesis, yet such high efficiency needs multiple, 2 or more light absorbers to achieve, total photovoltage above 1440 mV. In this report, we demonstrate visible light active Single light absorber -2 photons to 1 hydrogen (S2) overall water splitting via photovoltaic-electrochemical system that can be achieved by single junction solar cell, composed with CsPbBr₃ (band gap of 2.3 eV) solar cell with open circuit voltage larger than 1600 mV can power up water electrolyzer cell and achieves Solar to hydrogen efficiency of 1.7% with confirmed H₂ gas generation. Operating point shows possible STH of 5.0%. This result demonstrates its prospective on efficiency increment (max 12%) and Technoeconomic analysis (modest cost of 5.5 $/kg of hydrogen) in near future, as benchmark for S2 PV-EC system.