On the Operational, shelf life and degradation mechanism in polymer field effect transistors

Abstract

Organic Field Effect Transistors (OFETs) have shown great potential for future electronic technologies due to their low-cost solution processing, mechanical flexibility and potential applications for large area displays. One of the big obstacles in the realization of the practical applications is the inherent poor ambient stability of the OFETs. Here we report on the aging dependent degradation mechanism in the Poly[2,5-(2-octyldodecyl)-3,6-diketopyrrolopyrrole-alt-5,5-(2,5-di(thien-2-yl)thieno [3,2-b]thiophene)] (DPPDTT) based OFETs in the ambient conditions. These polymer OFETs showed the charge carrier mobility, threshold voltage and current on/off ratios in the range of 0.2 cm2V−1s−1, -15 V and 106 respectively. The device parameters showed variations in their values initially and then became stable with aging after ∼20% initial degradations in the ambient. We have correlated the degradation in the OFET performance parameters with the degradation in the polymer channel layer that is confirmed with a time dependent FTIR spectra. Our findings are thus important to understand and achieve stability in OFET devices by aging them.