Institute of Fundamental Technological Research

A novel thiophenic tetramer containing a cinnamate group in the side chain with a functionalization degree of 50% is reported. The tetramer was obtained by means of a simple and straightforward procedure involving the functionalization of a p-methoxyphenoxy substituted thiophenic precursor, which led to a soluble product with a good yield. The oligomer was fully characterized from a structural and chemical point of view and employed for the fabrication of small molecule organic solar cells exploiting the bulk heterojunction (BHJ) architecture. The presence of an UV-light sensitive group in the tetramer allowed the photocrosslinking of tetramer/PCBM blends, giving high values of photocurrent and conversion efficiency for the exposed samples. Moreover, the UV-treated devices showed improved stability, even upon heating for three days at 130 °C, thus confirming that photocrosslinking can strongly reduce phase segregation under severe operational conditions.

electronic materials, polymers, fullerenes, nanostructures, electrical characterization, semiconductors