Synthesis of perovskite Cs2SnI6 film via the solution processed approach: First study on the photoelectrochemical water splitting application

We report on the synthesis of perovskite Cs2SnI6 films via the solution–processed approach. The cubic Cs2SnI6 phase (Fm3m group) formed at the annealing temperature of 170 °C for 8 h in air has uniform morphology. The optical characteristics of the compound depended on the annealing temperature and the compound behaved like a direct band gap semiconductor. Based on these findings, we firstly investigated the potential application of Cs2SnI6 to photoelectrochemical (PEC) water splitting using a 0.3 M NaCl electrolyte. The photocurrent density (PCD) and photoconversion efficiency (η) were 0.92 mA cm−2 and 0.54% at −0.8 V, respectively. This might be suitable for fabricating the hybrid PEC device. •Synthesis of perovskite Cs2SnI6 film and high stable phase in air.•Controllable of Cs2SnI6 phase using the annealing approach.•A first study of photoelectrochemical characteristic of Cs2SnI6/FTO film with NaCl electrolyte.