Caglar Mujdat, Ilican Saliha, Caglar Yasemin, Sahin Yücel, Yakuphanoglu Fahrettin, Hür Deniz
Anadolu University, Faculty of Science, Department of Physics, 26470 Eskisehir, Turkey.
Spectrochim Acta A Mol Biomol Spectrosc. 2008 Nov 15;71(2):621-7. doi: 10.1016/j.saa.2008.01.022. Epub 2008 Jan 19.
The optical properties of sulfonated polyaniline (SPAN) thin film prepared by electrochemical method have been investigated. Polychromic behavior of SPAN thin film (transparent yellow-green-dark blue) was observed when the cyclic voltammograms were taken between -0.25 V and +1.90 V (vs. Ag/AgCl, sat.) during the growth of polyaniline film. In situ UV-vis spectra of the polymers-indium tin oxide (ITO) glass electrode were taken during the oxidation of the polymers at different applied potentials. The direct band gap values of SPAN thin film changed from 3.771 eV to 3.874 eV with the applied potentials. From in situ UV-vis spectra, the optical constants such as refractive index and dielectric constant of the SPAN thin film were determined. The important changes in absorption edge, refractive index and the dielectric constant were observed due to the applied potentials. The refractive index dispersion curves of the film obey the single-oscillator model and oscillator parameters changed with the applied potentials. The most significant result of the present work is in situ spectroelectrochemical method, which can be used to modify the optical band gaps and constants.
研究了用电化学方法制备的磺化聚苯胺（SPAN）薄膜的光学性质。在聚苯胺薄膜生长过程中，当循环伏安图在-0.25 V至+1.90 V（相对于饱和Ag/AgCl）之间采集时，观察到SPAN薄膜的多色行为（透明黄绿-深蓝）。在不同外加电位下聚合物氧化过程中，对聚合物-氧化铟锡（ITO）玻璃电极进行了原位紫外-可见光谱测定。SPAN薄膜的直接带隙值随外加电位从3.771 eV变化到3.874 eV。根据原位紫外-可见光谱，确定了SPAN薄膜的光学常数，如折射率和介电常数。观察到由于外加电位导致吸收边、折射率和介电常数发生重要变化。薄膜的折射率色散曲线符合单振子模型，振子参数随外加电位而变化。本工作最显著的成果是原位光谱电化学方法，该方法可用于改变光学带隙和常数。
