Molecular Design and Morphology Control Towards Efficient Polymer Solar Cells Processed using Non‐aromatic and Non‐chlorinated Solvents

Using an environmentally friendly solvent, N-methyl-2-pyrrolidone, a polymer with benzodithiophene (BDT) and thieno[3,4-b]thiophene (TT) monomers and triethylene glycol monoether (TEG) side chains, PBDTTT-TEG, can be processed into an active layer for a polymer solar cell (PSC). Combined with phenyl-C 71-butyric acid methyl ester (PC 71 BM) as the acceptor, the resulting PSC has a power conversion efficiency (PCE) of 5.23%. This is the first example of an efficient polymer solar cell fabricated from a non-aromatic and nonchlorinated solvent.