Oligomeric Acceptor Enables High-Performance and Robust All-Polymer Solar Cells with 17.4 Efficiency

摘要

Developing efficient and stable all-polymer solar cells (all-PSCs) hasreceived increasing attention because of their mechanical robustnessfor flexible devices. Based on the CH-series small molecule acceptors, anew polymer acceptor (PZC24) is reported and obtains a decent powerconversion efficiency (PCE) of 16.82 when blended with PM6. To furtherimprove the performance, an oligomeric acceptor (CH-D1), which possessesthe same backbone structure as PZC24, is proposed and synthesizedas the third component for all-PSC system. The creative strategyimproves the crystallinity and molecular packing, and can maintain theefficient charge transport channels of the all-PSCs binary system. Therefore,the PM6:PZC24:CH-D1 based ternary devices exhibit an impressivePCE of 17.40, among the highest value of all-PSCs. Compared to thePM6:PZC24, the ternary device exhibits enhanced photosoaking stabilityand thermal stability, simultaneously. In addition, the introduction of oligomericacceptor does not weaken the mechanical robustness of all-PSCs.As such, the ternary flexible devices display an excellent PCE of 15.35.Importantly, this strategy shows excellent universality in PM6:PY-IT andPM6:PY-V-γ all-PSCs with improved PCEs over 17. The results providea feasible strategy to simultaneously improve photovoltaic efficiency andstability of all-PSCs devices and herald a bright future for all-PSCs.