Recent Research Progress of n-Type Conjugated Polymer Acceptors and All-Polymer Solar Cells

The active layer of all polymer solar cells (all-PSCs) is composed of a blend of a p-type conjugated polymer (p-CP) as donor and an n-type conjugated polymer (n-CP) as acceptor. All-PSCs possess the advantages of light weight, thin active layer, mechanical flexibility, low cost solution processing and high stability, but the power conversion efficiency (PCE) of the all-PSCs was limited by the poor photovoltaic performance of the n-CP acceptors before 2016. Since the report of the strategy of polymerized small molecule acceptors (PSMAs) in 2017, the photovoltaic performance of the PSMA-based n-CPs improved rapidly, benefitted from the development of the A-DA'D-A type small molecule acceptors (SMAs). PCE of the all-PSCs based on the PSMA acceptors reached 17%-18% recently. In this review article, we will introduce the development history of the n-CPs, especially the recent research progress of the PSMAs. Particularly, the structure-property relationship of the PSMAs is introduced and discussed. Finally, current challenges and prospects of the n-CP acceptors are analyzed and discussed.

Automated summary

The active layer of polymer solar cells consists of a blend of p-type and n-type conjugated polymers. The poor photovoltaic performance of n-type polymers limited the power conversion efficiency of all-polymer solar cells before 2016. However, the development of polymerized small molecule acceptors (PSMAs) and A-DA'D-A type small molecule acceptors (SMAs) have greatly improved the photovoltaic performance of these solar cells, with recent efficiencies reaching 17%-18%. This review article discusses the development history and recent research progress of n-type conjugated polymers, particularly focusing on the PSMAs.