CsPbBr3 Quantum Dot Modified In2O3 Nanofibers for Effective Detection of ppb-Level HCHO at Room Temperature under UV Illumination

The design of high-performance and low-power formaldehyde (HCHO) gas sensors is of great interest to researchers for environmental monitoring and human health. Herein, In2O3/CsPbBr3 composites were successfully synthesized through an electrospinning and self-assembly approach, and their ultraviolet-activated (UV-activated) HCHO gas-sensing properties were investigated. The measurement data indicated that the In2O3/CsPbBr3 sensor possesses an excellent selectivity toward HCHO. The response of the In2O3/CsPbBr3 sensor to 2 ppm of HCHO was 31.4, which was almost 11 times larger than that of In2O3 alone. Besides, the In2O3/CsPbBr3 sensor also displayed extraordinary linearity (R-2 = 0.9696), stable reversibility, and ideal humidity resistance. Interestingly, the gas-sensing properties of the In2O3/CsPbBr3 sensor were further improved (R-a/R-g = 54.8) under UV light irradiation. Meanwhile, the response/recovery time was shortened to 7/9 s. The improvement of HCHO-sensing properties might be ascribed to the distinctive structure of In2O3 nanofibers, the adsorption capacity of cesium lead bromide quantum dots (CsPbBr3 QDs) for UV light, and the synergistic effect of heterostructures between the components. Density functional theory (DFT) was implemented to discuss the adsorption ability and electronic characteristics of HCHO at the surface of In2O3/CsPbBr3 composites. Especially, this research points out new constructive thoughts for the exploitation of UV light improved gas-sensing materials.