Impact of Mechanical Bending on the Performance of Organic Thin-Film Transistors and the Characteristic Temperature of the Density of States

A. Nikolaou, J. Leise, J. Pruefer (THM, Germany), U. Zschieschang, H. Klauk (MPI-Stuttgart, Germany), G. Darbandy (THM, Germany), B. Iñíguez (URV, Spain), A. Kloes (THM, Germany)

In this study, the effect of bending on the electrical characteristics of organic thin-film transistors is studied, using experimental data obtained from a large number of discrete organic transistors fabricated on a flexible polymeric substrates, in the coplanar device architecture. The transistors under bending-stress presented a significant drain-current degradation that can be mainly attributed to the respected reduction of the effective carrier mobility value. By correlating a power-law mobility model and the basics of percolation theory, the observed mobility degradation could be attributed to a decrease of the characteristic temperature that describes the shape of the Gaussian density of states in the utilized organic semiconductor. Overall, a maximum effective carrier mobility degradation of 45.9% due to bending, depending on the experimental conditions, can be reported.