Tellurophene-Based\nRandom Copolymers for High Responsivity and Detectivity Photodetectors

Abstract

Organic photodetectors\n(OPDs) have attracted great attention because of their advantages\nincluding tunable response range, easy processability, and flexibility.\nVarious conjugated polymers have been developed for high-performing\nOPDs. Herein, a series of tellurophene-based random copolymers containing\ntwo typical electron-withdrawing units naphthalene diimide (NDI) and\nperylene diimide (PDI) are designed and synthesized. Through varying\nthe ratio of PDI/NDI moieties of the analogous polymers, the optophysical\nproperties and film morphology, together with photodetector performances,\nare systematically tuned. It was demonstrated that the photodetectors\nbased on the polymer with the molar ratio of PDI/NDI units of 70/30\npossessed strong photoinduced absorption and favorable morphology\nvia transient absorption spectra and atomic force microscopy studies.\nAs a result, a high responsivity about 19.1 A/W at 600 nm and an excellent\ndetectivity more than 10¹² Jones ranging from 350 to 600\nnm were successfully achieved, which are among the highest values\nfor OPDs and comparable to inorganic counterparts.