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

Increasing electroluminescene quantum efficiency (EQE(EL)) of the photoactive layer to reduce non-radiative recombination energy loss (E-loss) has been demonstrated as an effective strategy to improve open-circuit voltage (V-oc) 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 V-oc. Herein, we report a highly fluorescent molecule (IT-MCA) as a third component to reduce the E-loss and enhance the V-oc for ternary OSCs. Applying the IT-MCA to three binary hosts, a significant increase of V-oc (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 V-oc.

Automated summary

This study demonstrates that incorporating a highly fluorescent molecule (IT-MCA) as a third component into the active-layer film of ternary OSCs can effectively reduce E-loss and enhance V-oc. This approach led to a significant increase in V-oc and achieved a best PCE with outstanding device stability.