Novel dithienopyrrole-based molecular donor materials for organic solar cells

A new molecule with dithieno[3,2-b:2’,3’-d]pyrrole (DTP) as central moiety and two terminal diketopyrrolopyrrole (DPP) units named DPP-DTPC8 has been designed and synthesized. The push–pull molecule exhibits excellent thermal stability, strong absorption in visible region, and matched energy levels. Devices fabricated from DTPC8:PC[Formula: see text]BM blend films exhibit the maximum power conversion efficiency of 2.75%, with Voc of 0.63 V, Jsc of 9.94 mA[Formula: see text] cm[Formula: see text], and FF of 43.8%. The active layers undergo thermal annealing or solvent vapor annealing treatments, exhibiting inconspicuous influence on the aggregation of the molecule. This study demonstrates that the new molecule DPP-DTPC8 tailored with DTP and DPP units could affect the thermal stability, absorption, energy levels and morphology that manage the photovoltaic performances.