Highly efficient, green-solvent processable, and stable non-fullerene polymer solar cells enabled by a random polymer donor

Abstract Rapid development of non-fullerene polymer solar cells (NF–PSCs) with high efficiency have gained wide research attention recently, however, high-performance large-area NF–PSCs are still lacking since most developed NF–PSCs use a thin active layer around 100 nm, which is not compatible with the fabrication of large-area devices. Herein, we fabricate high-performance and green-solvent processed NF–PSCs with thick active layer using a random copolymer (2TRA) and non-fullerene acceptors. Compared to its highly-crystallized analogue (2TRR), 2TRA with rearranged backbone enables better blend morphology, higher exciton generation rate, more efficient excitons dissociation, and less recombination in NF–PSCs. With O-IDTBR and IEICO-4F as non-fullerene electron acceptors, highly-efficient photovoltaic devices with PCE of 10.08% and 12.06% are achieved. Moreover, 2TRA-based NF–PSCs show good compatibility with multiple processing solvents, low sensitivity to the active layer thickness (up to 300 nm), and excellent photostability. The combined advantages of 2TRA-based solar cell devices indicate that 2TRA is a promising polymer donor for the application in large-area PSC modules through roll-to-roll technology, and the rearrangement design on polymer donors could be useful to design high-performance polymers for practical application.