Improved performance in TIPS-pentacene field effect transistors using solvent additives

The effect of solvent additives on the performance of 6,13- bis(triisopropylsilylethynyl) pentacene (TIPS-pentacene) field effect transistors (FETs) was investigated. Hole mobilities increased from 0.10 cm ² V^-1 s^-1 for pristine devices to 0.73 or 0.71 cm² V^-1 s^-1, when TIPS-pentacene FETs were processed with diphenyl ether (DPE) or chloronaphthalene (CN), respectively. In order to examine the impact of additives on the surface morphology, molecular ordering and crystallinity of TIPS-pentacene, scanning electron microscopy (SEM), X-ray diffraction (XRD) and optical microscopy measurements were carried out. Appropriate amounts of additives were found to induce the formation of well-ordered crystalline domains in TIPS-pentacene films, resulting in enhanced hole transport as well as consistent device performance. Additionally, reduced contact resistances were observed in devices processed with additives compared to neat TIPS-pentacene FET devices. Our findings indicate that the use of solvent additives constitutes a new and effective methodology for the fabrication of OFETs with improved performance.