Optical Fiber Hydrogen Sensor Based on Magnetron Sputtered Pd/V_2O_5 Films

摘要

Laminated thin films composed of V_2O_5 and Pd (or Pt-Pd) layers were deposited on glass substrates and the end faces of multimode optical fibers, and the sensitive behaviors of the thin films to hydrogen gas were studied using a UV-visible speetrophotometer and an optical fiber sensor's experimental setup. Both the thickness of the V_2O_5 layer and that of the Pd layer have obvious influences on the sensitivity performance of the Pd/V_2O_5, films. The Pd (30 nm) V_2O_5 (280 nm) film deposited on a glass substrate is sensitive to 0.1% hydrogen and the highest change in relative transmittance is about 25% when exposed to 4% hydrogen. PdV_2O_5, films were coated onto the end faces of multimode fibers to form optical fiber sensors. The response time of the Pd (20 nm) V_2O_5 (280 nm) sensor is about 50 s and the change in relative reflected light intensity is about 18°o upon exposure to 4% hydrogen. Deposition of Pt-Pd double layer instead of Pd signal layer over V_2O_5, can reduce the response time of the sensor. The response time of the Pd (20 nm). V_2O_5 (280 nm) sensor is about 50 s, while that of the Pt (10 nm)-Pd (10 nm)/V_2O_5 (280 nm) sensor is about 25 s.