The nanocomposite gate insulating film of a pentacene-based thin film transistor was deposited by inkjet printing. In this study, utilizing the pearl miller to crumble the agglomerations and the dispersant to well stabilize the dispersion of nano-TiO2 particles in the polymer matrix of the ink increases the dose concentration for pico-jetting, which could be as the gate dielectric film made by inkjet printing without the photography process. Finally, we realized top contact pentacene-TFTs and successfully accomplished the purpose of directly patternability and increase the performance of the device based on the nanocomposite by inkjet printing. These devices exhibited p-channel TFT characteristics with a high field-effect mobility (a saturation mobility of ？0.58？cm2？V？1？s？1), a large current ratio (>103) and a low operation voltage (<6？V). Furthermore, we accorded the deposited mechanisms which caused the interface difference between of inkjet printing and spin coating. And we used XRD, SEM, Raman spectroscopy to help us analyze the transfer characteristics of pentacene films and the performance of OTFTs. 1. Introduction Organic thin film transistors (OTFTs) for display recently have been studied widely because of potential application in low cost, large area, and suiting for flexible electronics. They can be fabricated by simple soluble processes. However, the field mobility of OTFTs is lower and the threshold voltage is higher than that of the amorphous Si (a-Si) TFTs. Gate dielectrics plays a significant role in modifying the ameliorating of a field effect OTFTs [1, 2]. Currently, high-k materials are other ideal candidates and most of them are based on inorganic ceramic, which require widely expensive deposition process and higher annealing temperature. One way is to combine the advantages of inorganic high-k nanoparticles with organic soluble polymers to form the nanocomposite dielectrics [2–7]. The nanocomposite (NC) film is incompetent for photography to pattern as insulators of active matrix arrays and was introduced consequently into some new direct printing technology such as inkjet printing. Recently, inkjet printing (IJP) process has been developed for electrical devices and become a promising instrument for the display industry because of the possibility in mask-free process and patternablility for nanoscale. In this study, we investigated the correlation of characteristics of printed NC-films with various solid phases which affects the performance of O-TFTs application. We mixed cross-linked poly-4 vinyl phenol (PVP) solution and
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