Transient Drain Current Measurement for Polymer Transistor Containing Residual Bromine Atoms

In this study, we investigated the transient drain current characteristics of organic field-effect transistors having poly(9,9-dioctylfluorene- co -bithiophene) (F8T2) as the semiconducting layer. When the F8T2 molecules contained a high concentration of residual bromine atoms, a large decrease in drain current – on the time scale of several milliseconds – was observed upon the application of gate voltage. This decrease in drain current can be fitted accurately using a stretched exponential equation, suggesting that bromine atoms in F8T2 form traps.