[10p-S203-1~21] 6.3 Oxide electronics

▲ [10p-S203-9] Facile control of V/Bi ratio in bismuth vanadate films by oxygen pressure in sputtering for enhanced photoelectrochemical performance

〇(D)Liu Jiaqi¹, Namiki Uezono¹, Sachin A. Pawar¹, Muhammad Monirul Islam¹, Shigeru Ikeda², Takeaki Sakurai¹ (1.Univ. of Tsukuba, 2.Konan Univ.)

Keywords:Bismuth vanadate film, Sputtering, Photocatalyst

In this work, the BiVO₄ photoanode films were fabricated by using sputtering with a single target BiV₂O_x. The various oxygen partial pressure was used in the sputtering to control the V/Bi ratio, efficiently and facilely (the Bi-rich films could be obtained by V-rich target). Interestingly, the V/Bi ratio of films has the linear relationship with respect to oxygen concentration, which was attributed to the different reaction order between V and Bi. The lifetime of carriers, which was related to the V/Bi ratio in films, was considered to be affected by V vacancies. Therefore, the lifetime did not increase any more when the V/Bi ratio reached a certain level. The extend in lifetime dramatically enhanced the photoelectrochemical (PEC) performance of prepared films. As a result, the photocurrent during water oxidation achieves 1.6 mA·cm⁻² at 1.23 V against the reversible hydrogen electrode (RHE) in a 0.4 mol L^-1 K₂HPO₄, 0.4 mol L^-1 KH₂PO₄ and 0.4 mol L^-1 K₂SO₄ (pH = 6.84) electrolyte.