Effect of Bias Stress in Inkjet-Printed Polymer Thin-Film Transistors: Generation and Annihilation of Subgap Density of States

Abstract

Here, we report investigations of the effects of bias stress on the density of states (DOS) in polymer thin-film transistors (PTFTs). As the active channel layer, these PTFTs employed an inkjet-printed semiconducting film of P8T2Z-C12 [poly (tetryldodecyloctathiophene-alt-didodecyl bithiazole)]. In positive bias stress tests, the threshold voltage (VT) of the inkjet-printed PTFT shifted in the positive direction. However, this shift was largely recovered when the PTFT was released from the bias stress. We analyzed the effect of the bias stress manifested by the VT shift using the full energy range of the subgap DOS versus the duration of the bias stress, which we obtained by applying various DOS extraction techniques.