Eur. Phys. J. E (2008) 26: 73-79
https://doi.org/10.1140/epje/i2007-10292-2

ISMC-2007

Layered TiO₂ :PVK nano-composite thin films for photovoltaic applications

TiO₂ :PVK nano-composite thin films

¹ Physik-Department, LS E13, TU München, James-Franck-Str. 1, 85747, Garching, Germany
² HASYLAB at DESY, Notkestr. 85, 22603, Hamburg, Germany

^* e-mail: muellerb@ph.tum.de

Received: 18 September 2007
Accepted: 8 February 2008
Published online: 15 April 2008

Abstract

The influence of the solvent used for spin-coating on the homogeneity of poly(N-vinylcarbazole) (PVK) films is investigated. Homogenous films are obtained only by the use of toluene, solution in tetrahydrofuran (THF) and chloroform results in radially oriented inhomogeneities and films prepared by use of N-methylpyrrolidone and dimethylacetamide show particle formation during spin-coating. Layered nano-composite thin films are prepared by spin-coating a PVK film on top of a nano-structured titanium dioxide ( TiO₂ layer. The TiO₂ thin films are prepared by a sol-gel process using an amphiphilic copolymer as structure-directing agent. Structural characterisation of the TiO₂ :PVK nano-composite films is done by field emission scanning electron microscopy (FESEM) and grazing-incidence small-angle scattering (GISAXS). Bare TiO₂ films are probed for comparison. Light is basically only absorbed in the ultraviolet regime and absorption slightly increases upon addition of PVK, which makes the layered TiO₂ :PVK nano-composite thin films good candidates for UV photovoltaic devices. Furthermore, absorption remains stable over a period of several days.