Integration of photoelectrochemical devices and luminescent solar concentrators based on giant quantum dots for highly stable hydrogen generation

Abstract

Hydrogen generation from water under sunlight illumination is the key to construct a sustainable and clean energy system. To date, the long-term stability of photoanodes based on colloidal quantum dots (QDs) for hydrogen generation remains a major challenge due to the degradation of the QDs and hole accumulation. The degradation is usually caused by the self-oxidation of QDs induced by ultraviolet radiation. Here, we propose a concept of integrating a luminescent solar concentrator (LSC) with a photoelectrochemical (PEC) cell into a standalone device to improve the stability of the PEC device for hydrogen generation by avoiding direct irradiation of ultraviolet light on PEC devices. In this study, CdSe/(CdS_xSe_1−x)₅/CdS core/multi-shell QDs were used as a photosensitizer. The PEC device based on alloyed multi-shell QDs shows a saturated photocurrent density of 11.5 mA cm⁻² and maintains ∼16.2% of its initial value after 23 hours of sunlight illumination (100 mW cm⁻²). PEC devices based on QDs coupled with an LSC exhibit a saturated photocurrent density of 1.2 mA cm⁻², and ∼84.6% of its initial value was retained after 23 hours of continuous illumination, indicating a 420% enhancement compared to a PEC device alone. This finding proves a unique concept to improve the photo-stability of PEC devices by coupling with an LSC.