The optical and electrical characteristics of SnO2 composite films with various contents (0.0.05, 0.1, 0.2, and 0.3 at.%) of Pt nanoparticles were evaluated. The Pt nanoparticles were synthesized by a methanol reduction method and their average size was controlled to 3 nm using poly(N-vinyl-2-pyrrolidone) as a protecting agent. The lowest resistivity of 2.031 x 10(-2) Omega cm was obtained in the SnO2 film containing 0.2 at.% Pt nanoparticles after annealing at 700 degrees C while its average transmittance in the visible region was 85.24%. The enhanced electrical properties were attributed to the increase of the carrier concentration and crystallinity of the films due to donation from Pt nanoparticles as well as the increased annealing temperature. Meanwhile, the slight degradation of the transmittance was due to scattering from the introduction of Pt nanoparticles and the increased crystallite size due to the increase of the annealing temperature to 700 degrees C. Well-defined 20-mu m wide direct-patterned composite SnO2 films containing Pt nanoparticles were formed by a simple photochemical metal-organic deposition process involving a photosensitive starting precursor. UV exposure, and removal of the unpatterned area by rinsing with solvent. Based on the results of this study, we suggest that direct-patternable SnO2 films with Pt nanoparticles can be easily applied to transparent electrodes in electrical devices without requiring an expensive and toxic process such as dry etching. (C) 2011 Elsevier B.V. All rights reserved.