Fiber optic room temperature ethanol sensor based on ZnSnO₃/TiO₂ with UV radiation sensitization

A fiber optic ethanol gas sensor with ZnSnO3 hollow cube/nano-TiO2 composite coating based on ultraviolet (UV) radiation sensitization was proposed, which can realize high sensitivity, high selectivity, and fast ethanol gas sensing at room temperature. The probe adopted a simple single-mode fiber (SMF)-multi-mode fiber-SMF structure. The ZnSnO3/TiO2 gas-sensitive film was coated on the sensing area by dip-coating method. Experiment results show that the probe sensitized by UV radiation has a linear sensitivity of 3.85 pm/ppm for ethanol gas at 0-250 ppm, which is about 6.6 times more sensitive than the probe without UV radiation (0.582 pm/ppm). In addition, the probe with UV radiation has good time measurement stability, a fast response time (response time is about 20 s, recovery time is about 60 s), and excellent ethanol gas selectivity. This study proves that UV radiation is an effective method to increase the sensitivity of gas sensing. This is also the first application of ZnSnO3/TiO2 composite material in fiber optic sensors. Combined with the advantages of fiber optic sensing, it shows anti-electromagnetic interference, micro size, high sensitivity, high selectivity, fast response, and remote sensing.