Doping characteristics of isoindoloindole-based conjugated polymer toward robust transformable organic conductor

Abstract As regards production of electric-charge carriers, blending of conjugate polymer (CP) with dopants is often less efficient than anticipated. When a novel CP (PIDF-BT) comprising long side chains and an electron-donating isoindoloindole derivative are subjected to molecular doping with 2, 3, 5, 6-tetrafluoro-7, 7, 8, 8-tetracyanoquinodimethan (F4-TCNQ), the resulting sequential doping provides higher electrical-conductivity compared to those obtained using conventional blending approaches. After treatment with the F4-TCNQ solution, the optimized CP film exhibits electrical-conductivity values exceeding 140 S cm−1 with enough long-term stability and flexibility. In addition, the doping efficiency was demonstrated to be scalable with respect to the exposure duration within the F4-TCNQ solution as well as its concentration. The obtained results in this study indicate clearly that CPs capable of maintaining low crystallinity levels are advantageous for use in sequential-doping applications whilst facilitating realization of high electrical conductivity.