用于低浓度H2 S 室温稳定监测的CsPbBr3 @TiO2 异质结微晶气体传感器.

Through a simple solution method, TiO(Acac)2 was used to in-situ coat the all-inorganic perovskite material CsPbBr3. After heating at 400 ℃, CsPbBr3 @ TiO2 core-shell structure microcrystals were directly prepared. The crystal structure, microscopic morphology, and chemical composition of CsPbBr3 @ TiO2 microcrystals were characterized using X-ray diffraction (XRD), scanning electron microscopy (SEM), high-resolution transmission electron microscopy (HRTEM), and X-ray photoelectron spectroscopy (XPS). It was confirmed that the in-situ metal oxide coating on the perovskite formed welldispersed spherical shell structures with sizes of 4 ~ 8 μm. A CsPbBr3 @ TiO2 thin film gas sensor was constructed on a fluorine-doped tin oxide (FTO) electrode using spin-coating method. The sensitivity of the sensor to H2 S gas was tested at room temperature. The results show that the sensor has a detection limit of 25 ppb (1 ppb = 10 -9) for H2 S gas, with a response and recovery time of 24/21 s to 100 ppb H2 S, and a sensitivity of 0. 59. The response curve exhibits good cyclic stability. Moreover, the sensor maintains over 90% stability within 30 d of exposure in air and possesses excellent gas selectivity and humidity resistance. Photoluminescence (PL) spectroscopy, time-resolved photoluminescence (TRPL) spectroscopy, ultraviolet-visible diffuse reflectance spectroscopy (UV-Vis), and ultraviolet photoelectron spectroscopy (UPS) were employed to analyze the band positions, charge dynamics, and coordination mechanisms. The sensing mechanism was elucidated using the oxygen adsorption principle. This work provides a new approach for the stable monitoring of low concentrations of H2 S gas at room temperature. [ABSTRACT FROM AUTHOR]