Ternary Polymer Solar Cells with Low-Cost P3HT as the Second Donor by the Complementary Absorption Region from Long-Wavelength to Medium-Wavelength Regions Forming Cascaded HOMO and LUMO Energy Levels

In this work, ternary polymer solar cells (PSCs) were constructed with PTB7-Th as the host donor, O-IDTBR as the acceptor, and P3HT as the third component material. Two binary PSCs showed different advantages. The PTB7-Th-based binary PSCs showed the advantage of high V-OC (1.03 V), while P3HT-based binary PSCs showed the advantage of a high fill factor (FF) (69.52%). P3HT can complement the medium-wavelength absorption spectra and allows efficient exciton dissociation due to the cascade's lowest unoccupied molecular orbital and highest occupied molecular orbital level between P3HT, PTB7-Th, and O-IDTBR. Therefore, the optimized ternary PSCs combine the advantage of two binary PSCs. The optimized ternary PSCs showed higher J(SC) and FF than PTB7-Th-based binary PSCs and higher V-OC than P3HT-based binary PSCs. P3HT can simultaneously enhance the arrangement of the blend donor to enhance crystallization, decrease roughness, and improve charge-carrier kinetic processes. In addition, the optimized ternary PSCs showed better thermal stability than PTB7-Th-based binary PSCs.

Automated summary

Ternary polymer solar cells were constructed with PTB7-Th, O-IDTBR, and P3HT, combining the advantages of two binary cells by complementing absorption spectra and enhancing exciton dissociation. The optimized ternary PSCs showed higher J(SC), FF, and thermal stability, indicating the potential for improved efficiency.