Non-Fully Conjugated Photovoltaic Materials with Y-Series Acceptor Backbone for High-Performance Organic Solar Cells^†

In the last few years, organic solar cells (OSCs) have made significant progress in photovoltaic performance, mainly due to the innovative development of active layer materials, especially Y-series and related derivatives as acceptors which have become the key factor that boosts the power conversion efficiency. Recently, to achieve high-performance OSCs, an emerging molecular design strategy of applying flexible alkyl units as linkers to construct non-fully conjugated acceptors has been developed and addressed great attention. This review highlights the non-fully conjugated photovoltaic materials with Y-series backbone that enable high-performance OSCs. Impressive OSCs have been achieved by some representative non-fully conjugated material systems. The related molecular design strategies are discussed in detail. Finally, a brief summary and future prospect are provided in advancing the non-fully conjugated photovoltaic materials with Y-series backbone towards the brighter future.