Optimal Sr-doped free TiO 2 @SrTiO 3 heterostructured nanowire arrays for high-efficiency self-powered photoelectrochemical UV photodetector applications

Abstract

Due to their high performance, photoelectrochemical ultraviolet (UV) photodetectors have attracted much attention, but the recombination of photogenerated electrons at the interface of photoanode/electrolyte limited further improvement of photoelectrochemical UV photodetectors (PEC UVPDs). Modification of TiO 2 photoanode by SrTiO 3 could improve the performance of UVPD, because the energy barrier that is established at the TiO 2 –SrTiO 3 interface could accelerate the separation of the photogenerated electrons-holes pair. However, the recombination center that is caused by the preparation of TiO 2 @SrTiO 3 core-shell heterostructured nanostructure decreases the performance of PEC UVPDs, which is still an important problem that hindered its application in PEC UVPDs. In this paper, we presented a Sr-doped free TiO 2 @SrTiO 3 core-shell heterostructured nanowire arrays as a photoanode for the self-powered PEC UVPD. This will not only accelerate the separation of the photogenerated electrons-holes pair, but it will also reduce the recombination of photogenerated electron-hole pairs in the photoanode. The intrinsic effect of SrTiO 3 reaction time on the J variations of UVPDs is investigated in detail. An impressive responsivity of 0.358 A·W −1 was achieved at 360 nm for the UVPD based on TiO 2 @SrTiO 3 core-shell heterostructured nanowire arrays, which heretofore is a considerably high photoresponsivity for self-powered photoelectrochemical UVPDs. Additionally, this UVPD also exhibits a high on/off ratio, fast response time, excellent visible-blind characteristic, and linear optical signal response.