Photoinduced Electron Transfer in Donor−Acceptor Double-Cable Polymers: Polythiophene Bearing Tetracyanoanthraquinodimethane Moieties

Abstract

To circumvent the problems of morphology and donor−acceptor phase segregation in organic bulk heterojunction solar cells, double-cable materials, consisting of a hole conducting conjugated polymer chain carrying pendant electron accepting moieties, are proposed. We report the electrochemical synthesis of a double-cable material consisting of a polythiophene backbone with covalently bound tetracyanoanthraquinodimethane (TCAQ) moieties. Cyclic voltammetry and UV−vis absorption measurements reveal that in this functional material both the polythiophene chain and the TCAQ moieties maintain their individual electrochemical and electronic ground state properties. Photoinduced absorption (PIA) and light-induced electron spin resonance (LESR) studies clearly indicate photoinduced electron transfer from the polythiophene backbone to the TCAQ moieties upon photoexcitation. The results of the PIA are comparatively studied with UV/vis and near-infrared absorption spectra upon electrochemical doping.