Basic study on the development of high performance gas-sensing system based on the holographic method.

目前的研究旨在通过理论和实验两方面的方法，利用全息光栅方法开发一种高性能的气体传感系统。研究的主要问题如下：1。全息图的制备及其表征通过将包覆的光抗蚀剂暴露在两束干涉的紫外激光下，在真空蒸发的Au薄膜、SnO2和ITO涂覆的玻璃基板上制备全息图。对曝光、冲洗、光学几何等条件进行了优化，以获得光基板作为传感材料具有更高衍射和更高曝光的全息图。利用金基全息图和ito基全息图对亚甲基蓝电极反应的初步研究结果表明，本方法可以监测衬底表面介电性能的变化。因此，该方法被用于研究硫醇在金全息图上的SA过程，该过程有望在无颜色变化的情况下进行。本文首次通过实验获得了SA结晶的动力学参数。利用金属氧化物半导体和基于sno2的全息图作为H2和co的传感器，测试了对可燃气体的全息响应。研究了影响反应时间和气体选择性的因素。杂化衬底可作为选择性检测感兴趣气体的全息图基材。由于该方法对表面光学常数的微小变化具有高度的敏感性，因此也可应用于TiO2基全息图光催化表面反应的研究。获得了在光催化过程中对亚单层吸附中间体进行原位监测的实验证据。

The present research has aimed, by both theoretical and experimental approaches, at the development of a high performance gas-sensing system using a holographic grating method. Those major issues studied are as follows :1.Preparation of holograms and their characterizationHolograms were prepared on vacuum-evaporated Au thin films, SnO2 and ITO coated glass substrates by exposing the overcoated photoresist to the interfering two UV-laser beams. Exposure, rinsing, optical geometry and other conditions were optimized to give holograms of higher diffraction and higher exposure of the bare substrate as sensing material.2.In situ monitoring of thiol self-asembly (SA) on Au-based hologramsPreliminary results on the electrode reaction of methylene bule using Au- and ITO-based holograms showed that the change in dielectric properties of the substrate surface are possibly monitored by the present method. Thus, the method was applied to study SA process of thiol on Au-hologram which is expected to proceed with no color change to be monitored. The kinetic parameters of SA crystalization was experimentally obtained for the first time.3.Holographic response to flammable gas by metal-oxide semiconductorsSnO2-based hologram was tested as sensor to H2 and CO.The response to the model gas was observed but found to be somewhat temperature dependent. Factors affecting the time response and the gas selectivity were also studied. Hybrid substrate was suggested to be useful as hologram base material for the selective detection of the gas of interest.4.In situ monitoring of the photocatalytic reaction on a TiO2 hologramSince the present method was shown to be highly sensitive to the small change in the surface optical constant it was also applied to the study of a photoinduced surface reaction of photocatalysis using TiO2-based hologram. The experimental proof of monitoring submonolayr adsorbed intermediates was obtained in situ during the photocatalysis.