N-type polymer semiconductors incorporating para, meta, and ortho-carborane in the conjugated backbone

We report on three novel n-type conjugated polymer semiconductors incorporating carborane in the polymer backbone and demonstrate their applicability in optoelectronic devices. Comparing the optoelectronic properties of para -, meta -, and ortho -carborane isomers revealed similar energetic characteristics between the different polymers, with the carborane unit acting as a “conjugation breaker”, confining electron delocalisation to the conjugated moieties. The fabrication of all-polymer organic photovoltaic (OPV) devices and thin-film transistors (TFTs) revealed some differences in device performance between the polymers, with the meta -carborane based polymer exhibiting superior performance in both OPV and TFT devices. • Comparing the use of p -, m -, and o -carborane in the backbone of conjugated polymers. • The carborane unit acts as a “conjugation breaker” in the conjugated system. • Varying the carborane isomer has a small impact on physical properties of polymers. • The polymers demonstrate applicability in OPV and TFT devices. • Different carborane isomers significantly impact device performance.