A star-shaped D–π–A small molecule based on a tris(2-methoxyphenyl)amine core for highly efficient solution-processed organic solar cells

Abstract

A new star-shaped D–π–A small molecule, 2,2′,2′′-{nitrilotris[(3-methoxy-4,1-phenylene)-2,2′-bithiene-5′,5-diyleth-1-yl-1-ylidene]}trimalononitrile N(Ph(OMe)-2T-DCN-Me)₃, with high efficiency potential for photovoltaic applications was synthesized. Introducing a soluble tris(2-methoxyphenyl)amine (TPA-MeO) core unit can significantly improve the solubility of star-shaped small molecules without negatively impacting intramolecular conjugation and intermolecular solid state arrangements. Solution-processed organic solar cells based on a blend of N(Ph(OMe)-2T-DCN-Me)₃ and PC₇₀BM show an initially high power conversion efficiency of over 4% under simulated AM 1.5.