LAUSR

Abstract This work describes an approach to direct evaluate the role of selected modifier added over hematite photoanode interfaces for light assisted water splitting. Hematite photoanodes with thickness varying from 25 up to 130 nm were designed via spin coating deposition of polymeric precursor that provides mesoporous planar morphology. The photoelectrochemical data analyzed in terms of global efficiency parameter (ηglobal) revealed a close dependence with hematite thickness for unmodified photoanode, which large number of interfaces associated with high charge recombination rate led to drop the electrode performance. To address this issue and manipulate the large number of interfaces due to the planar morphology, Sn4+ ions (1 and 3% molar ratio) were deposited over the hematite surface leading to enhance the electronic transport with a cost of creation of surface states at the solid-liquid interface. Then, a second modification process was done by photoelectrodeposition of Ni/Fe based material to suppress or minimizing the effect of surface state created by the Sn4+ ions addition. The results show that the interfacial traps were mitigated for the thinner hematite photoanodes, where the presence of Sn4+ and Ni/Fe significantly increases the ηglobal. The present find, highlights the importance of morphology design that allows a combination of modifier insertion to work in synergy for enhancing the overall photoanode performance.