A facile and novel route to improve TIPS pentacene based organic thin film transistor performance with elastomer

In this study, we report a facile route to regulate the crystallization and enhance charge transport of small-molecule organic semiconductors by blending with a rubbery polymer additive polyisobutylene (PIB). Using a solution-processed semiconductor 6,13-bis(triisopropylsilylethynyl) pentacene (TIPS pentacene) to mix with the PIB polymer, we show that the addition of PIB led to densely-arranged, lengthened TIPS pentacene needles with excellent long-range uniformity. Bottom-gate, top-contact organic thin-film transistors (OTFTs) based on TIPS pentacene/PIB hybrid film demonstrated a field-effect mobility of up to 0.15 cm²/Vs, and particularly, a 3-fold and 2-fold enhancement of average mobility and performance consistency (denoted by average mobility to standard deviation ratio). In addition, the effect of hexamethyldisilazane (HMDS) surfactant treatment on the semiconductor charge transport was studied. We ascribe such improved performance of TIPS pentacene/PIB blend OTFTs to the collaborative outcome of reduced crystal misorientation, diminished defects and charge trap centers, as well as a higher areal coverage. The effective method as demonstrated in this work can be generally implemented to attune the crystal growth and promote charge transport of newly-developed small-molecule organic semiconductors.