热处理对LiFe_(1-0.01x)Y_(0.005x)Ag_(0.005x)PO_4薄膜光波导传感元件气敏性的影响

Effect of Heat Treatment on LiFe_(1-0.01x)Y_(0.005x)Ag_(0.005x)PO_4 Thin Film Optical Waveguide′s Gas Sensing Properties

以FeSO4.7H2O,H3PO4,LiOH.H2O,AgNO3及Y(NO3)3.6H2O为原料,利用水热法一步合成出了LiFe1-0.01xY0.005xAg0.005xPO4粉体(x=0.5,1.0),并将该材料作为敏感试剂,用旋转-甩涂法做成纳米薄膜固定在锡掺杂玻璃光波导表面,在不同温度下进行热处理。采用紫外-可见分光光度计、测厚仪以及自组装的玻璃光波导气敏测试仪研究了热处理对LiFe1-0.01xY0.005xAg0.005xPO4薄膜光学及气敏特性的影响。研究结果表明:在450℃下进行热处理的薄膜元件具有良好的光学透明及较好的气敏特性。相同浓度的不同挥发性有机气体中,该传感元件对二甲苯气体有很好的选择性响应,其检测响应范围为1×10-7～1×10-3(V/V),响应-恢复时间分别小于5和100 s。

LiFe1-0.01xY0.005xAg0.005xPO4（x=0.5,1.0） was synthesized via hydrothermal method by one step using FeSO4 · 7H2O,H3PO4,LiOH · H2O,AgNO3 and Y（NO3）3 · 6H2O as precursors.LiFe1-0.01xY0.005xAg0.005xPO4 was selected as sensing materials and was subsequently utilized in a spin-coating procedure for the fabrication of LiFe1-0.01xY0.005xAg0.005xPO4 thin films,and then the coated film was dried at different temperatures.The effect of heat treatment on LiFe1-0.01xY0.005xAg0.005xPO4 thin film optical waveguide′s gas sensing properties were studied using ultraviolet spectrophotometer,ellipsometer and self assembled optical waveguide gases testing apparatus.The experimental results indicated that the thin film sensing element,which was dried at 450 ℃,was exhibited good sensing capabilities and optical transparent.The sensor had higher response to the xylene gas than the other various volatile organic compounds at same concentration.These sensors exhibited good response to xylene gas in the range of 1×10-7 to 1×10-3 with response and recovery times less than 5 and 100 s.