Solution-Based Phototransformation of C60 Nanorods: Towards Improved Electronic Devices

Abstract

A modified liquid–liquid interface precipitation synthesis of C60 nanorods, effects and opportunities following an in situ photochemical transformation in the liquid state, and an electronic characterization using a field-effect transistor (FET) geometry are reported. The nanorods feature a high aspect ratio of ≈103 and a notably small average diameter of 172 nm. Interestingly, it is found that a decreased nanorod diameter appears to correlate with distinctly improved electronic properties, and an average electron mobility of 0.30 cm2 V−1 s−1, as measured in a FET geometry, is reported for as-grown nanorods, with the peak value being an impressive 1.0 cm2 V−1 s−1. A photoexposure using green laser light (λ = 532 nm) is demonstrated to result in the formation of a polymer-C60 shell encapsulating a monomer-C60 bulk; such photo-transformed nanorods exhibit an electron mobility of 4.7 × 10−3 cm2 V−1 s−1. It is notable that the utilized FET geometry only probes the polymer-C60 nanorod surface shell, and that the monomer-C60 bulk is anticipated to exhibit a higher mobility. Importantly, photoexposed nanorods can be conveniently processed as a stabile dispersion in common hydrophobic solvents, and this finding is attributed to the insoluble character of the polymer-C60 shell.