Triphenylamine-containing D–A–D molecules with (dicyanomethylene)pyran as an acceptor unit for bulk-heterojunction organic solar cells

Abstract

Two new triphenylamine (TPA)-containing D–A–D molecules with TPA as the donor unit (D), (dicyanomethylene)pyran (PM) as the acceptor unit (A) and thienylenevinylene (TV) or 4-hexyl-thienylenevinylene (HTV) as the conjugated pi-bridge, TPA–TV–PM and TPA–HTV–PM, have been designed and synthesized for solution-processable organic solar cells (OSCs). The optical and electrochemical properties of these linear molecules were studied. The compounds exhibit broad absorption in the visible region with lower HOMO energy levels, which are desirable for application as a donor in organic solar cells. The OSC devices were fabricated by spin-coating the blend solution of the molecules as the donor and PC₇₀BM as the acceptor (1 : 3, w/w). The power conversion efficiency of the OSCs based on TPA–TV–PM and TPA–HTV–PM reached 2.06% and 2.10%, respectively, under the illumination of AM.1.5, 100 mW cm⁻².