New highly -conjugated bisalkynyl-linked oligomers of heteroatom-substituted perylene diimides: Optical and electronic properties and performance in perovskite solar cells

A series of four new oligomeric derivatives of NFA, NFA(S), NFA(Se) and NFA(N) with terminal perylene diimide groups modified with heteroatoms of S, Se, and N, were successfully synthesized and fully characterized by a variety of physicochemical methods. Due to deep LUMO levels, all compounds have an electron-acceptor character, which allows them to perform as electron transport compounds in perovskite solar cells of p-i-n architecture. The highest efficiency of 17.23 % was delivered by the solar cells with NFA(Se) electron transporting layer.