Reducing non-radiative recombination energy loss via a fluorescence intensifier for efficient and stable ternary organic solar cells

Increasing electroluminescene quantum efficiency (EQEEL) of the photoactive layer to reduce non-radiative recombination energy loss (Eloss) has been demonstrated as an effective strategy to improve open-circuit voltage (Voc) of organic solar cells (OSCs). Meanwhile, incorporating a third component into the active-layer film can improve power conversion efficiency (PCE) of resultant ternary OSCs, mostly contributed from increments in short-circuit current density and fill factor but less in the Voc. Herein, we report a highly fluorescent molecule (IT-MCA) as a third component to reduce the Eloss and enhance the Voc for ternary OSCs. Applying the IT-MCA to three binary hosts, a significant increase of Voc (41 mV) is acquired and a best PCE of 16.7% is obtained with outstanding device stability. This work provides a new guideline to design the third-component molecule by enhancing its fluorescence for efficient and stable ternary OSCs with improved Voc.