Thermally integrated photoelectrochemical devices with perovskite/silicon tandem solar cells: a modular approach for scalable direct water splitting

Abstract

Direct solar water splitting appears to be a promising route to produce hydrogen, avoiding competition for electricity with other important economic uses. Halogenated hybrid perovskites recently enabled the demonstration of efficient and potentially low-cost photoelectrochemical cells and PV-coupled electrolysers, reaching high efficiencies but so far limited to a small active area of a few mm², in the case of perovskite/silicon tandem solar cells. Here, we show the added value of integrating a thermal exchanger into the system thanks to additive manufacturing, providing a thermally integrated photoelectrochemical cell (IPEC) with performance doubled compared to the device without any heat exchanger (from 3.3 to 8% STH). In addition, we develop a modular approach to scale-up this concept from 7.6 to 342 cm², highlighting statistical variations in the efficiency of single integrated photoelectrochemical cells and their origin. We conduct an outdoor stability test for 72 hours, achieving a STH performance of 6.3%, and investigate the causes of device degradation through the easy disassembly of the integrated photoelectrochemical devices. We identify the interface between the perovskite layer and p-layer as critical for achieving stable photoelectrochemical devices integrating perovskite/silicon tandem solar cells.