The research on optical chemical sensing characteristics of the dye-doped sol-gel coating film

研究了基于染料掺杂的溶胶-凝胶涂层薄膜的荧光作为光学化学传感器在光学pH传感器和光学湿度传感器中的应用，考察了基于影响的样品制备条件对传感特性的影响。染料掺杂的溶胶-凝胶涂层薄膜是一种光学pH传感器，香豆素-4-、香豆素-6-和荧光素掺杂的溶胶-凝胶涂层薄膜的荧光表现出与pH的依赖关系，从而使分子表现出酸碱平衡。因此，它在光学pH传感器中具有应用的可能性。这些光学pH传感特性如下：(1)对荧光强度的pH具有良好的响应范围和响应速度。提出了在香豆素-4掺杂的溶胶-凝胶涂层中利用两个荧光波长的强度比来提高荧光强度稳定性的方法。结果表明，罗丹明6G与香豆素6和荧光素共掺杂时，其发光表现出从香豆素6和荧光素到罗丹明6G的能量转移。罗丹明6G的荧光pH依赖于能量转移，具有应用于光学pH传感器的可能性。染料掺杂的溶胶-凝胶涂层薄膜作为光学湿度传感器，香豆素-4-、香豆素-6-、荧光素和罗丹明6G掺杂的溶胶-凝胶涂层薄膜的荧光随湿度的变化而变化，有应用于基于荧光的光学湿度传感器的可能性。结果表明，荧光湿度依赖关系可分为两类：(1)分子聚集和单体分子的荧光猝灭；(2)酸碱平衡引起的荧光变化。

The application to optical pH sensor and optical humidity sensor as an optical chemical sensor based on the fluorescence of a dye-doped sol-gel coating film was considered, and the effect based sample preparation condition of sensing characteristics was examined.1. Dye-doped sol-gel coating film as an optical pH sensor.The fluorescence of coumarin-4-, coumarin-6- and fluoresein-doped sol-gel coating films shows pH dependence so that the molecule may show acid-base equilibrium. Therefore, it has the application possibility to the optical pH sensor. These optical pH sensing characteristics are as follows.(1) It is excellent in respect of response range and response speed for pH of the fluorescence intensity. However, it is lacking for the stability for pH of the fluorescence intensity.(2) The method for using the intensity ratio at two fluorescent wavelengths for the improvement on the stability was done in a coumarin-4-doped sol-gel coating film. As the result, it was proven that the effect by the preparation condition was big, though to some extent improvement was accepted.And, when rhodamine6G is doped together with coumarin6 and fluorescein in sol-gel coating films, its emission showed energy transfer from coumarin6 and fluoresein to rhodamine6G.The fluorescent pH dependence of rhodamine6G by the energy transfer has the application possibility to the optical pH sensor.2. Dye-doped sol-gel coating film as an optical humidity sensor.The fluorescence of coumain-4-, coumarin-6-, fluoresein- and rhodamine6G-doped sol-gel coating films changes by moisture, and there is the application possibility to the optical humidity sensor based on the fluorescence. It was proven that the fluorescent humidity dependence was classified into two of (1) the fluorescence quenching of molecular aggregation and the monomer molecule, and (2) change of the fluorescence by acid-base equilibrium.