Organic/Inorganic Nano-hybrids with High Dielectric Constant for Organic Thin Film Transistor Applications.
The organic material soluble polyimide (PI) and organic-inorganic hybrid PI-barium titanate (BaTiO3) nanoparticle dielectric materials (IBX, where X is the concentration of BaTiO3nanoparticles in a PI matrix) were successfully synthesized through a sol-gel process. The effects of various BaTiO3contents on the hybrid film performance and performance optimization were investigated. Furthermore, pentacene-based organic thin film transistors (OTFTs) with PI-BaTiO3/polymethylmethacrylate or cyclic olefin copolymer (COC)-modified gate dielectrics were fabricated and examined. The hybrid materials showed effective dispersion of BaTiO3nanoparticles in the PI matrix and favorable thermal properties. X-ray diffraction patterns revealed that the BaTiO3nanoparticles had a perovskite structure. The hybrid films exhibited high formability and planarity. The IBX hybrid dielectric films exhibited tunable insulating properties such as the dielectric constant value and capacitance in ranges of 4.0-8.6 and 9.2-17.5 nF cm-2, respectively. Adding the modified layer caused the decrease of dielectric constant values and capacitances. The modified dielectric layer without cross-linking displayed a hydrophobic surface. The electrical characteristics of the pentacene-based OTFTs were enhanced after the surface modification. The optimal condition for the dielectric layer was 10 wt% hybrid film with the COC-modified layer; moreover, the device exhibited a threshold voltage of 0.12 V, field-effect mobility of 4.32 × 10-1cm2V-1s-1, and on/off current of 8.4 × 107.
Department of Materials Engineering, Ming Chi University of Technology, No. 84, Gongzhuan Rd., Taishan Dist., New Taipei City, 24301, Taiwan. yyyu@mail.mcut.edu.tw.|Department of Chemical and Materials Engineering, Chang Gung University, No.259, Wenhua 1st Rd., Guishan Dist., Taoyuan, 33302, Taiwan. yyyu@mail.mcut.edu.tw.
Yang-Yen
YY
Yu
Department of Materials Engineering, Ming Chi University of Technology, No. 84, Gongzhuan Rd., Taishan Dist., New Taipei City, 24301, Taiwan.
Ai-Hua
AH
Jiang
Department of Chemical Engineering and Biotechnology, National Taipei University of Technology, No 43, Keelung Rd., Sec.4, Da'an Dist., Taipei, 10607, Taiwan. wenyalee@ntu.edu.tw.
Wen-Ya
WY
Lee
Barium titanate; Hybrid films; Modified layer; Polyimide; Sol–gel method