Annealing Temperature Dependence of the Size of C60 Clusters in C60-Doped Silicon Oxide Films

Abstract

C60-doped silicon oxide thin films were prepared by spin-coating a viscous solution formed upon soaking at 40°C an acidic toluene/ethanol solution of C60, phenyltriethoxysilane, and tetraethoxysilane with a C60–to–Si molar ratio of 2.5 × 10−3. The films were submitted to annealing at 300–500°C in Ar to investigate variation in the size of C60 clusters embedded in the films by photoluminescence spectroscopy. The film before annealing was found to contain the clusters consisting of ca. 60 C60 molecules, suggesting that C60 is present well-dispersed in the film. The molecules in the film aggregated to increase the size with increasing annealing temperature, indicating that the molecules diffuse easily in the film upon heating and therefore the size of the clusters is controllable with the annealing temperature.