Manipulating Charge Transfer and Transport via Intermediary Electron Acceptor Channels Enables 19.3% Efficiency Organic Photovoltaics

Balancing and improving the open-circuit voltage (V-oc) and short-circuit current density (J(sc)) synergistically has always been the critical point for organic photovoltaics (OPVs) to achieve high efficiencies. Here, this work adopts a ternary strategy to regulate the trade-off between V-oc and J(sc) by combining the symmetric-asymmetric non-fullerene acceptors that differ at terminals and alkyl side chains to build the ternary OPV (TOPV). It is noticed that the reduced energy disorder and the enhanced luminescence efficiency of TOPV enable a mitigated energy loss and a higher V-oc. Meanwhile, the third component, which is distributed at the host donor-acceptor interface, acts as the charge transport channel. The prolonged exciton lifetime, the boosted charge mobility, and the depressed charge recombination promote the TOPV to obtain an improved J(sc). Finally, with synergistically improved V-oc and J(sc), the TOPV delivers an optimal efficiency of 19.26% (certified as 19.12%), representing one of the highest values reported so far.

Automated summary

By adopting a ternary strategy to regulate the structure of symmetric-asymmetric non-fullerene acceptors, a balance between open-circuit voltage and short-circuit current density can be achieved in organic photovoltaics, leading to higher efficiency.