Photocurrent Generation of Poly(3,4-ethylenedioxythiophene)-on-TiO₂Nanoparticle

Abstract

The photocurrent generation of poly(3,4-ethylenedioxythiophene) (PEDOT) grown on TiO 2 nanoparticles were examined. PEDOT was deposited on the surface of mesoporous TiO 2 nanoparticle by chemical polymerization of 3,4-ethylenedioxythiophene (EDOT) under oxidative condition, to afford blue colored conductive particles, having average diameter of 80 nm when the feed ratio between TiO 2 and EDOT was 1:1.5 by weight. A photoelectrode coated with the PEDOT-onTiO 2 nanoparticles showed much higher photocurrent generation for a redox couple of hydroqunone and quinone, compared to that of PEDOT or TiO 2 only. The photoelectrode prepared from PEDOT-on-TiO 2 nanoparticles (ratio 1=2) showed photocurrent higher than 2.8 lA=cm 2 upon excitation with UV light under an external potential of À0.4 V (versus Ag=AgCl). The current generation and photoswitching properties was maximized when the feed ratio between TiO 2 and PEDOT was 1:2.

Highly stable organic–inorganic junction composed of hydrogenated titania nanotubes infiltrated by a conducting polymer

“…The observed enhancement is signicantly higher under UV-Vis and Vis irradiation than that described for the heterojunction composed of pEDOT:PSS and titanium dioxide nanoparticles. 68 Improved photoactivity of H-TiO 2 NTs/pEDOT:PSS in comparison with its pure counterparts results from formation of a p-n heterojunction when appropriate alignment of conduction and valence band positions of both ptype and n-type semiconductors allows for charge separation at the organic/inorganic heterojunction. 69 According to Haring et al, 70 in the case of conducting polymer-TiO 2 composite, there are three criteria for efficient hybrid bulk heterojunction: (a) Fermi level of TiO 2 to be close to its conduction band, (b) the difference between conduction band and LUMO should equal at least 0.3 eV, 71 and (c) Fermi level should be higher when compared with energy polarons level in the separated materials.…”