Copolymers of Thiophene and Cyano-Substituted Phenylene: Facile Tuning of Electronic Energy Levels and their Photovoltaic Application

A series of copolymers of thiophene and different molar ratios of DOCNP have been synthesized and characterized. The copolymers exhibit interesting tunable electronic energy levels and optoelectronic properties. The LUMO energy levels of the copolymers decreased with increasing DOCNP content, while the HOMO levels changed only a little. The copolymer films show broad absorption and high absorption coefficients in the visible region, which could be beneficial to the application as photovoltaic materials in solar cells. The results show that the introduction of a proper amount of electron‐acceptor groups in the polymer main chains induces an extension of the absorption spectra and improves the photovoltaic properties of the copolymers.