Study of PEDOT:PSS-SnO₂ nanocomposite film as an anode for polymer electronics

Poly(3,4-ethylenedioxythiophene) oxidized with poly(4-styrenesulfonate) (PEDOT:PSS) is a candidate material for applications in molecular electronics, such as organic field effect devices, organic photovoltaics, and organic light emitting devices. The properties of 3.5-4.0 nm sized SnO₂ nanoparticles doped PEDOT:PSS films were investigated for anode application. Sheet resistance was decreased and rms roughness was slightly increased with the incorporation of SnO₂ nanoparticles. However, the connectivity of conducting grains was improved by the plasticizing effect of surface -OH groups of SnO₂ nanoparticle. Using photoemission spectroscopy and near edge X-ray absorption fine structure (NEXAFS), the electronic structure of the films is studied comparatively on the C 1s NEXAFS, secondary electron emission cut off, and valence band spectra. The start of electron emission retarded and valence band maximum was increased in the PEDOT:PSS-SnO₂ nanocomposite films. These changes in the electronic structure resulted from emitted electron screening of core-hole in the PEDOT:PSS energy band and electron donation of SnO₂ nanoparticles.