FePc induced highly oriented PIID-BT conjugated polymer semiconductor with high bias-stress stability

Abstract

Polymer semiconductors with high crystallinity and high molecular orientation have been demonstrated to be in favor of improving the bias-stress stability of organic field-effect transistors (OFETs). The isoindigo (IID)-bithiophene (BT) based conjugated polymer (PIID-BT) is a typical donor–acceptor polymer with higher hole mobility and can be used for the bias-stress stability study. In this work, we use a small organic molecule of FePc to optimize the morphology and structure of the PIID-BT semiconductor to improve the bias-stress stability of OFET devices. The high crystallinity and ordered morphology of the FePc-doped PIID-BT film are realized, and this as-obtained FePc-doped PIID-BT OFET shows more outstanding bias-stress stability, with a lower drain current decay of only 12% over a stressing time of 1000 s than that of ca. 50% for the pristine PIID-BT devices. The electronic structure features reveal the bind between FePc and PIID-BT molecules via the Fe-O coordination interaction, which would be responsible for the efficiently oriented growth of the PIID-BT polymer and eventually promote the bias-stress stability of PIID-BT based OFET devices.