Enhanced Self-Powered Broadband Photodetectors Based on 1-D TiO₂/V₂O₅ Core-Cell Heterojunction

Self-powered photodetectors (PDs) based on heterostructured nanocomposites have been widely studied but are still being explored for further performance enhancement in bandwidth and photoresponsivity. Herein, we report a self-powered PD operating in ultraviolet and visible (UV-Vis) regions, which was prepared by incorporating of 1-D vanadium pentoxide (V2O5) nanorods (VNRs) with 1-D TiO2 nanorod arrays (TNRAs) for enhancing the photoelectric performance. A low-cost hydrothermal method was used to prepare the powder of VNRs and freestanding TNRAs on the F-doped tin oxide (FTO) glass substrate, respectively. The single-wall carbon nanotubes (SWCNTs) were incorporated with VNRs to form the SWCNTs@VNRs nanocomposite for enhancing the conductivity of V2O5. The self-powered broadband PDs were assembled as ITO/SWCNTs@VNRs/TNRAs/FTO configuration. Experimental results show that, without external bias, the typical sensitivity of the optimum PD can reach around 4.2, 1.2, and $0.6~\mu $ A/mW $\cdot $ cm $^{-{2}}$ for UV light of 360 nm and visible lights of 460 and 510 nm, respectively. It is suggested that the incorporation of the SWCNTs-modified 1-D VNRs with the 1-D TNRAs enables the formation of V2O5/TiO2 heterojunction network, effectively promoting the transportation and separation of photogenerated charges in the heterostructure and thus enhancing photoresponse performance of PDs.