Engineering perovskite solar cells for photovoltaic and photoelectrochemical systems: strategies for enhancing efficiency and stability

Solar-driven fuel production, including photovoltaic-electrochemical (PV-EC) and photoelectrochemical (PEC) water splitting as well as CO₂ reduction reaction (CO₂RR), presents a viable approach to mitigating carbon emissions. One of the major obstacles in developing efficient PV-EC and PEC systems lies in identifying suitable photoabsorbers that can effectively harness solar energy while maintaining stability under operating conditions. Despite their intrinsic instability in such environments, halide perovskites have garnered significant attention as promising photoabsorbers due to their exceptional optoelectronic properties, which are essential for facilitating efficient electrochemical reactions. This review first provides a concise overview of the mechanisms underlying water splitting and the CO₂RR, followed by an examination of the structural configurations and performance evaluation metrics of PV-EC and PEC systems. Next, the design and engineering of perovskite solar cells (PSCs) are explored, with an emphasis on optimizing light absorption, charge transport layer engineering, and addressing stability issues. Recent advancements in enhancing the efficiency and operational stability of PV-EC and PEC systems incorporating PSCs are then summarized. Finally, key challenges currently being addressed in the field are discussed, along with perspectives on future research directions. This review aims to support researchers in further advancing this technology toward the commercial production of green hydrogen.