Enhanced Performance Consistency in Nanoparticle/TIPS PentaceneBased Organic Thin Film Transistors

© 2011 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim Adv. Funct. Mater. 2011, 21, 3617–3623 In this study, inorganic silica nanoparticles are used to manipulate the morphology of 6,13-bis(triisopropylsilylethynyl)-pentacene (TIPS pentacene) thin fi lms and the performance of solution-processed organic thin-fi lm transistors (OTFTs). This approach is taken to control crystal anisotropy, which is the origin of poor consistency in TIPS pentacene based OTFT devices. Thin fi lm active layers are produced by drop-casting mixtures of SiO 2 nanoparticles and TIPS pentacene. The resultant drop-cast fi lms yield improved morphological uniformity at ∼ 10% SiO 2 loading, which also leads to a 3-fold increase in average mobility and nearly 4 times reduction in the ratio of measured mobility standard deviation ( μ Stdev ) to average mobility ( μ Avg ). Grazing-incidence X-ray diffraction, scanning and transmission electron microscopy as well as polarized optical microscopy are used to investigate the nanoparticle-mediated TIPS pentacene crystallization. The experimental results suggest that the SiO 2 nanoparticles mostly aggregate at TIPS pentacene grain boundaries, and 10% nanoparticle concentration effectively reduces the undesirable crystal misorientation without considerably compromising TIPS pentacene crystallinity.