Unusual Doping of Donor−Acceptor-Type Conjugated Polymers Using Lewis Acids

Conjugated polymers that can undergo unusual nonoxidative doping were designed. A series of polymers based on donor–acceptor–donor (DAD) moieties 2,1,3-benzoselenadiazole, 2,1,3-benzothiadiazole, 2,1,3-benzoxadiazolebenzo[2,1,5]oxodiazole, and 2-hexylbenzotriazole as acceptor fragments and 3,4-ethylenedioxyselenophene (EDOS) and 3,4-ethylenedioxythiophene (EDOT) as donor fragments was prepared. When the studied polymers were reacted with Lewis acids and bases, notable optical switching and conductivity changes were observed, evidencing the exceptional case of efficient nonoxidative doping/dedoping. Remarkably, in previously reported works, coordination of Lewis acids causes band gap shift but not doping of the conductive polymer, while in the present study, coordination of Lewis acid to highly donating EDOT and EDOS moieties led to polymer doping. The polymers show remarkable stability after numerous switching cycles from neutral to doped states and vice versa and can be switched both electrochemically an...