Direct patterning of SnO₂ composite films prepared with various contents of Pt nanoparticles by photochemical metal-organic deposition

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 × 10^{- 2} Ω cm was obtained in the SnO₂ film containing 0.2 at.% Pt nanoparticles after annealing at 700 °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 °C. Well-defined 20-μm 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.