In situ measurement of photostability of CdSe/CdS/ZnO nanowires photoelectrode for photoelectrochemical water splitting

Abstract

Quantum dot sensitized photoanodes have drawn much attention due to their high potential as efficient anodes for photoelectrochemical (PEC) water splitting or solar cells. However the photocorrosion of QDs is the crucial barrier for applications in these devices. The in situ analysis of photocorrosion is important in understanding its mechanism and also developing the possible solution for photocorrosion. In this study we have developed a novel, integrated analysis system for in situ measurements of photocorrosion and PEC performances. We have fabricated the CdSe/CdS/ZnO nanowire (NW) arrays on quartz crystal microbalance (QCM) as a platform for usage as PEC photoanodes and also mass analysis at the same time. The in situ measuring of photocurrents and mass changes were performed with continuous operation of PEC cells for CdSe/CdS/ZnO NWs photoanode. The study exhibited highly correlated tendency in photocurrent decrease and mass reduction, due to photocorrosion of CdSe/CdS/ZnO NWs. Also to improve the photostability of CdSe/CdS/ZnO NWs, applications of passivation and catalysts were studied and their effects were discussed. Our integrated in situ analysis system is highly applicable to various semiconductor sensitized systems.