Simply Complex: The Efficient Synthesis of an Intricate Molecular Acceptor for High-Performance Air-Processed and Air-Tested Fullerene-Free Organic Solar Cells

A perylene diimide (PDI) flanked diketopyrrolopyrrole (DPP) π-conjugated small molecule has been synthesized through an efficient and sustainable direct heteroarylation protocol. When paired with the donor polymer PTB7-Th, air-processed and tested bulk-heterojunction (BHJ) organic solar cells (OSCs) achieved a high power conversion efficiency (PCE) of 5.6%. The new acceptor showed favorable morphological changes upon solvent vapor annealing leading to a near 3-fold increase in PCE. This result is among the best reported utilizing DPP-based acceptors in air-processed and tested OSCs. All solar cells exhibited good air and light stability over a 35-day evaluation period.