Simple-Structured Acceptor with Highly Interconnected Electron-Transport Pathway Enables High-Efficiency Organic Solar Cells

Achieving desirable charge-transport highway is of vital importance for high-performance organic solar cells (OSCs). Here, it is shown how molecular packing arrangements can be regulated via tuning the alkyl-chain topology, thus resulting in a 3D network stacking and highly interconnected pathway for electron transport in a simple-structured nonfused-ring electron acceptor (NFREA) with branched alkyl side-chains. As a result, a record-breaking power conversion efficiency of 17.38% (certificated 16.59%) is achieved for NFREA-based devices, thus providing an opportunity for constructing low-cost and high-efficiency OSCs. Charge transport plays a significant role in determining the performance of organic solar cells (OSCs). Here, a highly interconnected electron-transport pathway in simple-structured nonfused-ring electron acceptor (NFREA) is achieved by manipulating the alkyl-chain topology. Therefore, the 3TTB-4F with branched alkyl side-chains demonstrates a record-breaking power conversion efficiency of 17.38% (certified 16.59%), establishing it as the highest efficiency among NFREA-based OSCs. image