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 (<i>R</i>² = 0.9696), stable reversibility, and ideal humidity resistance. Interestingly, the gas-sensing properties of the In₂O₃/CsPbBr₃ sensor were further improved (<i>R</i>_a/<i>R</i>_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.