Welcome to JOURNAL OF SYNTHETIC CRYSTALS! Today is Share:

JOURNAL OF SYNTHETIC CRYSTALS ›› 2024, Vol. 53 ›› Issue (10): 1815-1826.

• Research Articles • Previous Articles     Next Articles

CsPbBr3@TiO2 Heterojunction Microcrystals Gas Sensor for Low-Concentration H2S Stability Monitoring at Room Temperature

LU Jianghao1, HUANG Sheng1, CHEN Lu1, CHENG Yongchao1, GAO Shasha1, TAO Xueyu1, GU Xiuquan1,2   

  1. 1. School of Materials Science and Physics, China University of Mining and Technology, Xuzhou 221116, China;
    2. State Key Laboratory of Silicon and Advanced Semiconductor Materials, Zhejiang University, Hangzhou 310027, China
  • Received:2024-06-14 Online:2024-10-15 Published:2024-10-21

Abstract: 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 well-dispersed 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 H2S gas was tested at room temperature. The results show that the sensor has a detection limit of 25 ppb (1 ppb=10-9) for H2S gas, with a response and recovery time of 24/21 s to 100 ppb H2S, 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 H2S gas at room temperature.

Key words: CsPbBr3, perovskite, core-shell structure, heterojunction, H2S gas sensor, oxygen adsorption principle

CLC Number: