Acridine-Substituted-Centronucleus Nonfullerene Acceptors Enables Organic Solar Cells with Over 20% Efficiency with...

In this work, we propose a novel strategy of introducing luminescent acridine units for central nuclear substitution in quinoxaline-based acceptor molecules (named AQx-o-Ac and AQx-m-Ac) to enhance their photoluminescence quantum yields (PLQY), which can effectively improve the electroluminescent quantum efficiency (EQE_EL) of OSCs and thereby suppress ΔE_nr. In addition, the substituted acridine unit accelerates molecular aggregation and optimizes molecular crystallization, effectively alleviating the static disorder of acceptor molecules and facilitating charge extraction and transport in OSCs. As a result, the PM6:AQx-m-Ac binary OSCs achieve an excellent PCE of 18.64% with an exceptionally low ΔE_nr of 0.166 eV. To the best of our knowledge, a ΔE_nr of 0.166 eV represents the lowest value reported for OSCs achieving PCEs over 18 %. Finally, the acceptor AQx-m-Ac is incorporated into PM6:eC9 blend as the third component, and the optimal ternary device produces a superior PCE of 20.28%. This work highlights the potential of promoting luminescence for suppressing nonradiative energy loss and charts a viable path for upcoming breakthrough in high-efficiency organic photovoltaics.