Integrated halide perovskite photoelectrochemical cells with solar-driven water-splitting efficiency of 20.8%

Achieving high solar-to-hydrogen (STH) efficiency concomitant with long-term durability using low-cost, scalable photo-absorbers is a long-standing challenge. Here we report the design and fabrication of a conductive adhesive-barrier (CAB) that translates >99% of photoelectric power to chemical reactions. The CAB enables halide perovskite-based photoelectrochemical cells with two different architectures that exhibit record STH efficiencies. The first, a co-planar photocathode-photoanode architecture, achieved an STH efficiency of 13.4% and 16.3 h to t(60), solely limited by the hygroscopic hole transport layer in the n-i-p device. The second was formed using a monolithic stacked silicon-perovskite tandem, with a peak STH efficiency of 20.8% and 102 h of continuous operation before t(60) under AM 1.5G illumination. These advances will lead to efficient, durable, and low-cost solar-driven water-splitting technology with multifunctional barriers. High-efficiency photoelectrodes, which integrate light absorption with catalysis, have been limited to costly materials. Here, the authors develop an anticorrosion barrier that enables low-cost semiconductors for integrated solar fuel devices with 20.8% solar-to-hydrogen energy conversion efficiency.