Detection of hydrogen concentration based on an all-fiber fluorescence intensity ratio optical thermometer with Er3+/Yb3+ codoped NaBi(WO4)2 phosphors

Abstract

The detection of hydrogen concentration was realized by measurement the change of local environmental temperature using an all-fiber fluorescence intensity ratio (FIR) optical thermometer. The temperature sensing optical material Er3+/Yb3+ codoped NaBi(WO4)2 phosphors were synthesized and used for the development of temperature sensing probe. Intense green upconversion luminescence was observed at an excitation power of 1.5 mW at room temperature and the dependence of FIR on the environmental temperature was obtained at the temperature range of 298.15–373.15 K. The maximum absolute temperature sensitivity reached the maximum value of 0.0127 K−1 at 373.15 K and the absolute error was 0.4 K to 0.3 K at 303.15 K, which laid the foundation for further research on real-time and remote H2 concentration detection. The local temperature change ∆T was measured due to the heat release from the reaction of H2 embedded with Pt-loaded WO3/SiO2 film. The relationship between ∆T and H2 concentration was established, which may be used to detect the leakiness of H2 gas during the traffic and storage process.