Simultaneously Enhancing the Jsc and Voc of Ternary Organic Solar Cells by Incorporating a Medium-Band-Gap Acceptor

Ternary organic solar cells (OSCs) are fabricated with a PM6:Y6 blend film as the host system and a medium-band-gap (MBG) acceptor (BTIC-Cl) with a high-lying lowest unoccupied molecular orbital (LUMO) energy level as the third component. The ternary blend film PM6:Y6:BTIC-Cl (1:1.2:0.2, wt/wt) possesses a more favorable morphology, better ordered face-on pi-pi stacking, higher charge mobilities, and more balanced charge transfer than the binary blend films and other ternary blend films. As a result, the ternary OSC with the ratio of 1:1.2:0.2 shows an impressive power conversion efficiency of 16.60% with synchronously enhanced J(sc) of 27.25 mA cm(-2) and V-oc of 0.86 V, which are distinctly superior to those of the binary OSCs based on PM6:Y6 (15.50%) and PM6:BTIC-Cl (12.66%). These results provide an insight into the role of an MBG small-molecule acceptor with a high-lying LUMO energy level in ternary OSCs.

Automated summary

In this study, ternary organic solar cells using PM6:Y6:BTIC-Cl blend film demonstrated an impressive power conversion efficiency of 16.60%, with enhanced charge transfer properties and morphology compared to binary and other ternary blend films. The high-lying LUMO energy level of the MBG small-molecule acceptor played a crucial role in achieving superior performance in ternary OSCs.