Control of thermal and optoelectronic properties in conjugated poly (3-alkylthiophenes)

The optoelectronic and thermal properties of conjugated polymers are frequently tuned via direct synthetic modification of the conjugated repeat unit. It is also well known that these properties are inherently tied to the crystal structure, a factor which is difficult to predict upon slight chemical modification. We show that the crystal structure of random copolymers of 3-alkylthiophenes can be controlled, which in turn affects the optoelectronic properties. Furthermore, we show that the melting transitions smoothly vary between that of the two homopolymers. As such, the composition of copolymers is a convenient handle to predictably control the thermal properties, crystalline morphology, and optoelectronic properties simultaneously.