Solution Processing with a Good Solvent Additive for Highly Reliable Organic Thin-Film Transistors

Abstract

High-performance transistors require homogeneous crystalline thin films with high charge carrier mobilities on large substrates. We report a versatile solution process that uses a good solvent additive with a high boiling point. This method enables the fabrication of uniform, large-area, polymer thin films with improved thin film crystallinity and electrical characteristics and high reliability organic transistors. We demonstrate here that the addition of a small amount of a good solvent additive with a high boiling point to the processing solution is highly effective in not only inducing the strong self-assembly of the conjugated polymer during film solidification by increasing the solvent evaporation time but also in ensuring the formation of a uniform film morphology. These characteristics were found to enhance the device performance of a poly(3-hexylthiophene) film processed from a mixed solvent containing chlorobenzene and 1,2,4-trichlorobenzene, which was found to exhibit a highest average field-effect mobility of 0.012 cm 2 V –1 s –1 with excellent reliability over a 16 device array.