High-sensitivity photoelectrochemical visible-blind ultraviolet detector using SrTiO₃ nanocrystalline for weak irradiation

We have demonstrated a photoelectrochemical solar-blind ultraviolet (UV) detector based on SrTiO₃ (STO) nanocrystalline film in this work. The assembled UV detector presents a high on/off ratio of about 6433 under periodic UV irradiation, a high photocurrent density of 220.6 μA cm⁻², and a fast response time of 9 ms. By introducing a block layer (BL) on fluorine-doped tin oxide substrate, the response and decay times are shortened to 6 ms and 8 ms, respectively. The BL plays a crucial part in hindering the recombination of electrons from electrolyte carriers and avoiding short circuits. Due to its excellent light capture capability, the detector based on SrTiO₃ nanocrystalline exhibits high sensitivity to weak UV light (5 μW cm⁻²). Moreover, the detector also exhibits visible-blind characteristics and a good linear response. (paper)