Eco-friendly solvent engineering for high-performance solution-processed organic thin-film transistors

초록

In this study, we investigated the effect of binary green solvents containing high-boiling point (high-b.p.) solvent additives on the crystallinity of 6,13-bis(triisopropylsilylethynyl)pentacene (TIPS-pentacene) thin-films and the corresponding electrical performance of organic thin-film transistors (OTFTs). Solvent properties, such as dielectric constants and Hansen solubility parameters (HSPs), guided the selection of three binary solvent system: i-butyl acetate (iBA) + i-amyl acetate (iAA) (set 1), t-amyl methyl ether (tAME) + i-amyl acetate (iAA) (set 2), and anisole (ANI) + methyl laurate (ML) (set 3). To investigate how the addition of the selected high-b.p. solvent additive affects the interactions and extent of thin-film formation of TIPS-pentacene, both solution and thin-film UV-Vis spectra were measured. Microstructure, macroscopic morphology, and surface morphology of the TIPSpentacene thin-films were analyzed using X-ray diffraction (XRD), cross-polarized optical microscopy (cPOM) and atomic force microscopy (AFM), respectively. To evaluate the effect of semiconductor thin-film properties on electrical performance, top-contact/bottom-gate (TC/BG) OTFTs were fabricated. Among three sets, average hole mobility increased by up to three times, with the highest mobility of 3.13 cm2/V & sdot;s and current on/off ratio of 106 for set 1.

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