Upscaling Metal-Halide Perovskite Driven Photoelectrochemical H₂ Production System with > 10% Efficiency

Hydrogen (H₂) production through photoelectrochemical (PEC) water splitting (WS) can be generated using water and sunlight. To achieve a feasible PEC-WS system in field-relevant conditions, the primary requirements are solar-to-hydrogen (STH) efficiency of 10%, stability, and scalability. Scalable PEC-WS systems have been studied nowadays because of the confined integration of large-area photoelectrodes; however, several scalability issues are of concern, including choice of material, inexpensive large-area fabrication techniques, durability of the material, and maintaining high STH efficiency. Next-generation photovoltaic (PV) materials—organic-inorganic hybrid perovskites (PSK)—are a potential choice for photoelectrodes due to their superior optoelectronic and charge-transport characteristics and scalability to achieve practically viable PEC-WS technology. Nevertheless, these PSK materials have primary issues of humidity and low photostability when used as photoelectrodes in PEC-WS, in which the device must be immersed in water during illumination.

In this talk, we will present efficient, crystalline, and intrinsically stable formamidinium lead triiodide (FAPbI₃) as a light absorber for designing metal-encapsulated PSK photoelectrodes using pinhole-free Ni foil loaded with low-cost multi-metal oxide cocatalysts as OER and HER reactions, respectively. This talk will also present how passivated chlorine-doped FAPbI₃ (Cl:FAPbI₃) photoanodes and photocathodes, using UV-susceptible SnO₂ as an electron transport layer design and stabilized cocatalyst, can achieve high photocurrent, low onset potential, and stability of two days. A photoanode’s conversion efficiency of 12.73% and a half-cell solar-to-hydrogen efficiency of 14.04% in PSK photocathodes can be achieved. Lastly, we will introduce an integrated artificial leaf, a 4 × 4 array (16 cm²) with an STH efficiency of >10% even when scaled to a full size, enabling stable solar H₂ production under 1-sun conditions. Achieving the target of 10% STH efficiency in this bias-free type PEC-WS indicates that other scalable PSK materials (all-PSK and PSK-Si tandem) will eventually be the option for the design and development of >15% efficient practical solar H₂ production systems on a large scale.