Optimal Sr-Doped Free TiO2@SrTiO3 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 TiO2 photoanode by SrTiO3 could improve the performance of UVPD, because the energy barrier that is established at the TiO2–SrTiO3 interface could accelerate the separation of the photogenerated electrons-holes pair. However, the recombination center that is caused by the preparation of TiO2@SrTiO3 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 TiO2@SrTiO3 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 SrTiO3 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 TiO2@SrTiO3 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.

Application of Nanostructured TiO2 in UV Photodetectors: A Review

“…Many other oxides, such as Co 3 O 4 , [191] WO 3 , [192] Co 0.7 Ni 0.3 O, [193] GO, [194] Al 2 O 3 , [195] MoO 3 , [196] TiO 2−x H x , [197] SrTiO 3 , [198] MgO, [199] In 2 O 3 , [200] ZnTiO 3 , [101] and Cu 2 O [201] have also been integrated with TiO 2 in the form of either multilayered or core-shell architectures to improve the photodetection performance of TiO 2 -based PDs. For example, Mahala et al [191] developed a TiO 2 /Co 3 O 4 multilayer heterojunction by applying a stable, simple, and scalable reactive sputtering technique for UV and visible-blind photovoltaic applications.…”

“…PECC-type PDs that exhibit the photovoltaic effect and that are easy to fabricate with higher photocurrents compared with p-n junctions and Schottky junctions, have been developed. Ni et al [198] prepared a core-shell-structured Sr-doped TiO 2 /SrTiO 3 NWA, which has been used as a photoanode for a PECC UV PD, which shows high responsivity of 358 mA W −1 and an excellent on-off ratio of 2.8 × 10 4 under 360 nm UV illumination at 0 V bias. The results indicate that the TiO 2 /SrTiO 3 heterojunction not only accelerates the separation of photogenerated electron-hole pairs, but also limits the recombination of photogenerated electron-hole pairs at the interface of the photoanode/electrolyte.…”

“…Many other oxides, such as Co 3 O 4 , [ 191 ] WO 3 , [ 192 ] Co 0.7 Ni 0.3 O, [ 193 ] GO, [ 194 ] Al 2 O 3 , [ 195 ] MoO 3 , [ 196 ] TiO 2− x H x , [ 197 ] SrTiO 3 , [ 198 ] MgO, [ 199 ] In 2 O 3 , [ 200 ] ZnTiO 3 , [ 101 ] and Cu 2 O [ 201 ] have also been integrated with TiO 2 in the form of either multilayered or core–shell architectures to improve the photodetection performance of TiO 2 ‐based PDs. For example, Mahala et al.…”

Facile Fabrication of SrTiO3@MoS2 Composite Nanofibers for Excellent Photodetector Application

“…e light pollution mainly originated from assimilation lighting and massive use of architectural glass, particularly in the developed region. To solve this problem, photodetector has been widely studied as optoelectronic devices [6][7][8].…”