Efficient Continuous Light‐Driven Electrochemical Water Splitting Enabled by Monolithic Perovskite‐Silicon Tandem Photovoltaics

Solar‐assisted water electrolysis is a promising technology for storing the energy of incident solar irradiation into hydrogen as a fuel. Here, an integrated continuous flow electrochemical reactor coupled to a monolithic perovskite‐silicon tandem solar cell is demonstrated that provides light‐driven electrochemical solar‐to‐hydrogen conversion with an energy conversion efficiency exceeding 21% at 1‐Sun equivalent light intensity and stable operation during three simulated day‐night cycles.