Synthesis of SnO2-SnS2/SiO2 photonic-crystal-structure device for ultra-highly sensitive fluorescence sensing of NO2

High-sensitivity fluorescent sensing of nitrogen dioxide (NO 2 ) gas at room temperature remains a critical challenge to be overcome currently. In this work, a thin-film device (TFD) based on photonic-crystal film (PCF) was synthesized for the fluorescence sensing of NO 2 (1–100 ppm) with a 120 s response time, and exhibited obvious signal feedback to NO 2 concentration as low as 100 ppb. A wealth of experimental data indicates that its ultra-high sensitivity primarily originates from the following aspects. The structure of the PCF leads to the enhancement of the fluorescence signal, and the SiO 2 nanospheres constituting the PCF increase the surface area of the TFD, laying a solid foundation for detection. By inducing the SnO 2 -SnS 2 heterojunction on SiO 2 nanospheres, the TFD can efficiently capture NO 2 molecules and convert them into NO 2 − , facilitating detection. Furthermore, Rhodamine 6G (R6G) is selected as the probe molecule, which is commercially available and has excellent physicochemical properties for the sensing of NO 2 , endowing the TFD with high selectivity. The prepared SnO 2 -SnS 2 /SiO 2 TFD demonstrates promising application prospects in the context for visualizable detection of low-concentration NO 2 in explosive production and storage workshops, coal mines, and other high-explosive environments. • The detection devices were fabricated with photonic-crystal films. • NO 2 detection was achieved at room temperature. • Fluorescence detection of 1–100 ppm NO₂ within 120 s was realized. • The devices' detection limit was as low as 100 ppb. • The devices were potentially applicable to high-risk explosive environments.