LIN YONG-YAO (林永耀)a, MO DANG (莫党)a, GONG KE-CHENG (龚克成)b, ZHANG GUI-PING (张贵萍)b
a Department of Physics, Zhongshan University, Guangzhou 510275, China; b Polymer Structure and Modification Research Laboratory, South China University of Technology, Guangzhou 510641, China
Abstract We report the ellipsometric spectrum studies on a new kind of conducting polymers, polyaniline. In the UV-visible range (1.4-4.8eV photon energy region) the absorption coef-ficient, the complex dielectric function and the refractive index of polyaniline as functions of photon energy are obtained. The spectra of nonconducting and fully conducting polyaniline have been analyzed and discussed. The experimental results show that the emeraldine base form of polyaniline has a large energy gap (Eg～3.6eV) and its absorption spectrum shows a broad exciton absorption peak centered at 2 eV. The absorption spectrum of emeraldine salt after protonation have four absorption peaks centered at 1.5, 1.83, 3.0 and 3.88eV. We also investigated the spectrum evolution of the samples from nonconducting ($\sigma$<10-9$\Omega$-1·cm-1) to conducting ($\sigma$≈10+1$\Omega$-1·cm-1) states, and give the dielectric function and the refractive index of the samples.
Received: 24 November 1992
Accepted manuscript online:
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