Layer-by-Layer Processed Efficient All-Polymer Solar Cells Based on a Nonfused Polymerized Small Molecule Acceptor

The development of polymer acceptors is of crucial importance for all-polymer solar cells (all-PSCs). However, the state-of-the-art polymer acceptors are typically based on Y-series small molecule acceptors. Their synthetic complexity and high synthesis cost remain a severe challenge for future practical application of organic photovoltaics. Herein, a novel non-fused polymer acceptor named PDO is synthesized. The all-PSC achieves a best power conversion efficiency of 9.68% in the layer-by-layer (LBL) processed device, which is much better than that (8.14%) of the conventional bulk-heterojunction device. Comprehensive analysis on the electrical and morphological characterizations reveal that the improved device performance in the LBL-processed device is originated from efficient exciton extraction and charge transport, suppresses charge recombination, improves molecular ordering, and optimizes active layer morphology. These results validate that the fabrication of all-PSCs with non-fused polymerized small molecule acceptors is a promising strategy to develop low-cost and high-performance all-PSCs.