A Hybrid Dielectric Ink Consisting of up to 50 wt% of TiO2 Nanoparticles in Polyvinyl Alcohol （PVA）

作     者：Saumen Mandal Rahul Sharma Monica Katlyar 

作者机构：Department of Materials Science & Engineering Indian Institute of Technology Kanpur 208016 India Samtel Centre for Display Technologies Indian Institute of Technology Kanpur 208016 India 

出 版 物：《Journal of Chemistry and Chemical Engineering》 (化学与化工（英文版）)

年 卷 期：2012年第6卷第7期

页      面：625-630页

学科分类：081702[工学-化学工艺] 08[工学] 0817[工学-化学工程与技术] 0822[工学-轻工技术与工程] 

主　　题：Dielectric constant organic dielectric titanium dioxide nanoparticle polyvinyl alcohol low voltage operation. 

摘      要：PVA （Polyvinyl Alcohol） is a water soluble organic dielectric, easily solution processed to fabricate films by spin coating, dip coating or inkjet printing. It has been used as a dielectric layer in OTFTs （organic thin film transistors）, and its dielectric constant is around 3.5-10. For OTFTs operating at lower voltage, it is desirable to increase the dielectric constant. Here, we report a technique to incorporate upto 50 wt% of TiO2 nanoparticles （15-25 nm） in PVA to increase its dielectric constant. Rutile phase of TiO2 is used, because of its higher dielectric constant （e = 114） compared to anatase phase （E = 31）. We have made inks containing 10 and 50 wt% （of PVA） TiO2 nanoparticles, which is stable upto six months. PVA-TiO2 dispersions and PVA （without TiO2） were spin coated on indium tin oxide coated polyethylene terephthalate substrate. Film structure was studied using SEM （scanning electron microscopy）. Absorption study of the films confirms presence of TiO2 nanoparticles. M-I-M capacitors were fabricated by thermally evaporating aluminium on top of the dielectric films. We observed enhancement in dielectric constant by a factor of 2 for PVA containing 50 wt% TiO2 in comparison to PVA＇s dielectric constant. There is no concomitant increase in the leakage current.