The Preparation Of TiO₂ And SnO₂ Hollow Nanoparticles And Their Applications Inself-powered Ultraviolet Photodetectors

Ultraviolet(UV) photodetectors have attracted extensive research interest for their potential scientific and industrial applications, including remote control, chemical and biological analysis, water purification, environmental monitoring, flame detection, early missile plume detection and secure space-to-space communications. Ti O2(anatase 3.2 e V and rutile 3.0 e V) has emerged as a promising candidate for its unique physical stability, chemical inertness and excellent photoelectronic properties. In this paper, we have fabricated hollow nanomaterials as the photoanode for self-powered UVPDs by designing a simple operation, low cost, two-step hydrothermal method. Details as follows:Firstly, we synthesized the Fe2O3 nanonspindles template with uniform size of 450~500 nm in length by hydrothermal precipitation and fabricated Fe2O3@Ti O2 hierarchical nanostructures with titanium tetrafluoride, glycol, acetic acid and templates. Then we explored the most outstanding structures and analyzed growth mechanism preliminaryly by changing the concentration of titanium tetrafluoride and acetic acid, temperature, heating time.Secondly, we explored the optimal etching parameter for the preparation of hollow Ti O2 nanoparticles, and thus obtained hollow nanostructures 450~500 nm in length and with 200~250 nm in diameter by this parameter, the nanorods at the surface are about 60 nm in length and 10 nm in diameter. The Ti O2 hollow nanoparticles prepared in this paper have the characteristics of controllable size, simple operation, low cost, etc. The material has potential applications in environment and energy. Simultaneously, we synthesized Sn O2 hollow nanoparticles as the contrast.Thirdly, A novel self-powered UV photodetector(UVPD) based on the photoelectrochemical cell(PECC) has been constructed using the hollow Ti O2 spindles with nanorods. This self-powered UVPD displays a higher photocurrent density compared to the UVPD with the pure Sn O2 hollow spheres. By means of external quantum efficiency(EQE), UV-vis absorption, and electrochemical impedance measurements, we scrutinize the intrinsic role of the Ti O2 coating layer on the photocurrent enhancement. Under UV irradiation, this UVPD exhibits a high on/off ratio of 26538, a fast rise time of 0.004 s and decay time of 0.008 s, together with the excellent visible-blind characteristic and linear optical signal response. The self-powered photodetector is a promising candidate for application in high-sensitivity and high-speed UVPDs.