Modular perovskite-BiVO4 artificial leaves towards syngas synthesis on a m2 scale

Abstract

Metal halide perovskite-based artificial leaves have emerged in recent years as a promising design towards direct solar fuel synthesis. However, the complexity of these layered devices and reliance on solution-based techniques hinders the scalability and performance of existing prototypes. Here, we utilise vacuum processing of the perovskite light absorbers, as an industrially compatible method to produce large-scale devices. Accordingly, we fabricate fully evaporated 10 cm² PV devices sustaining a 1 V photovoltage, which allow perovskite-BiVO₄ tandem photoelectrochemical devices with a selective Cu₉₂In₈ alloy catalyst to sustain unassisted water and CO₂ splitting over 36 hours. To demonstrate the modularity of this approach, we designed a 0.7 × 0.5 m² “artificial tree” reactor containing a 10 × 10 array of artificial leaves, which was benchmarked during the 3-days final of the EIC Horizon Prize “Fuel from the Sun”, through an outdoor demonstration at the Joint Research Center of the European Commission in Ispra, Italy. Such real-world tests reveal key insights into practical operation that are not encountered during standardised laboratory experiments, but are crucial for upscaling of emerging solar fuel technologies.