Self-assembly crystal microribbons with nucleation additive for high-performance organic thin film transistors

Abstract

We demonstrate fabrication of 6,13-bis(triisopropylsilylethynyl) pentacene (TIPS pentacene) crystal microribbon based organic thin film transistors (OTFTs) with a solvent exchange method and the addition of a nucleation agent. TIPS pentacene crystals were formed via self-assembly as a result of solubility difference between the double solvents. At the same time, 4-hexylbenzoic acid (HBA) was added as a nucleation agent and formed an interfacial layer on the silicon dioxide gate dielectrics, which dispersed the aggregated crystals and enhanced its morphology uniformity. TIPS pentacene crystal microribbon based OTFTs with HBA nucleation additive showed a hole mobility of up to 0.36 cm2 V−1 s−1, and particularly, a 9-fold enhancement in average mobilities, as compared to pristine crystal based OTFTs. The remarkable enhancement in device performance can be attributed to the improved crystallinity, reduced defects and charge trap centers located at the grain boundaries, and controlled crystallization and dispersion effect due to the addition of the HBA nucleation agent.