A ladder-type poly(phenyl-co-methacryl silsesquioxane) (PPMSQ) copolymer was developed for use as a gate dielectric in high-performance organic field-effect transistors (OFETs). The ladder-type PPMSQ copolymer was synthesized via the hydrolysis of two types of monomers, methacryloxypropyltrimethoxysilane and phenyltrimethoxysilane, followed by a condensation polymerization. The phenyl groups in one monomer were introduced to enhance the structural ordering of the overlying organic semiconductors, whereas the methacryloxypropyl groups in the other monomer were introduced to cross-link the polymer chains via thermal- or photocuring. The curing process enhanced the electrical strength of the gate dielectric layer due to the formation of a network structure with a reduced free volume. Thermal curing reduced the surface energy of the gate dielectrics, which improved the structural order of the overlying organic semiconductors and promoted the formation of large grains. The ladder-type PPMSQ was used as a gate dielectric to produce benchmark p- and n-channel OFETs based on pentacene and N,N′-dioctyl-3,4,9,10-perylenedicarboximide (PTCDI-C8), respectively. The resulting OFETs exhibited excellent electrical performances, including a high carrier mobility (0.53 cm2 V-1s-1 for the p-type pentacene OFET and 0.17 cm2 V-1s-1 for the n-type PTCDI-C8 OFET) and a high ON/OFF current ratio exceeding 104. The photocured patterned PPMSQ film was successfully used to fabricate complementary OFET-based inverters that yielded high gains. The use of the ladder-type PPMSQ gate dielectrics provides a novel approach to realizing next-generation organic electronics.
Bibliographical noteFunding Information:
The copolymer was supported from Electronic Materials Division in DongJin Semichem, Korea. This work was financially supported by a grant from the Center for Advanced Soft Electronics (CASE) under the Global Frontier Research Program (2013M3A6A5073177) and Basic Science Research Program (2013R1A1A2011897, 2013R1A1A1008628, and 2009-0083540) of the National Research Foundation of Korea (NRF) funded by the Ministry of Education, Science and Technology, Korea. G.A. and H.K. acknowledge the support from NRF-2014R1A2A1A10052454.
All Science Journal Classification (ASJC) codes
- Electronic, Optical and Magnetic Materials
- Physical and Theoretical Chemistry
- Surfaces, Coatings and Films