Highly efficient GeSe micro-air-brick-based thin film standalone solar water-splitting photoelectrode with solar-light-soaking accumulation process

Abstract

A GeSe film with a novel micro air brick (MAB) structure presented quite interesting fast and efficient solar thermal generation properties. In this work, for the first time, we found that the solar thermal response feature of GeSe MABs significantly enhanced the solar water-splitting reaction itself. Combining a Bi₂Te₃ thermal electronic electrode with a GeSe MAB-based photoelectrode greatly increased the utilization efficiency of the waste energy of the infrared spectrum and the above-bandgap part. The synergistic coupling effect of solar thermal and photoelectrochemical water-splitting is very interesting for promoting the efficiency of not only GeSe MAB-based photoelectrodes, but also photoelectrodes for solar hydrogen evolution. It was found that the solar thermal energy captured by the GeSe MABs could be transformed into electrical power by the Bi₂Te₃ electrode, which can also be recycled/added to the GeSe MAB-based photoelectrode to assist the solar water-splitting reactions or power other power-consuming equipment. The solar thermal energy could be transformed into an additional electrical bias of approximately 1.52 V on the GeSe MAB-based photoelectrode itself, which significantly improves the solar-to-hydrogen (STH) efficiency of the GeSe photoelectrode. The Bi₂Te₃ thermal electric electrode in tandem with the GeSe MAB-based photoelectrode (Bi₂Te₃–GeSe MAB-integrated photoelectrode) could directly split water without any additional bias under only solar light irradiation. The Bi₂Te₃–GeSe MAB integrated photoelectrode presented a remarkable and record STH efficiency of over 13.5% after a brief solar-light-soaking accumulation process.