Thermal and electrical characterization of Polyvinyl Alcohol focusing on organic electronics applications

While most of the research on the area of organic field effect transistors (OFET) concentrates on the development and characterization of the semiconductor, the dielectric layer plays an important role on the performance of the device. PVA is an attractive candidate to this role due to its favorable properties. The structure of the polymer can be engineered through different parameters, which can be used to optimize the characteristics of the film depending of the desired properties. In this work we report an evaluation of the effect of different molecular weight, hydrolysis degree, and reticulation on the performance of the PVA to be applied as a gate dielectric in OFET. The methodology created simplifies the characterization of the dielectric material, excluding the influence of the semiconductor. The analysis of polymer structure was made by DSC analysis and the analysis of the film properties was based on the study of MIS capacitors. Crosslinkage presents the major impact on the polymer properties, followed by degree of hydrolysis, due to their large influence on chain mobility. An increase on chain mobility affects positively dielectric response and negatively insulation capacity, generating the need of compromise between these two properties. The largest drawback encountered was the high sensitivity of the films to environmental conditions, especially moisture, which contributed negatively to increase on hysteresis.