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) p 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.