Prolonging charge carrier lifetime via reinforcing molecular stacking for high-efficiency organic solar cells

Limited charge carrier lifetime (tau) leads to the short charge carrier diffusion length (LD) and thus impedes the improvement of power conversion efficiencies (PCEs) of organic solar cells (OSCs). Herein, anthracene (AN) as the additive is introduced into classical donor: acceptor pairs to increase the tau. Introducing AN efficiently enhances the crystallinity of the PM6:BTP-eC9+ blend film to reduce the trap density and increase the tau to 1.48 mu s, achieving the prolonged LD. The prolonged LD enables the PM6:BTP-eC9+ blend film to gain weaker charge carrier recombination, reduced leakage current, and shorter charge carrier extraction time in devices, compared with PM6: BTP-eC9 counterparts. Therefore, PM6:BTP-eC9+ based OSCs achieve higher PCEs of 18.41%+/- 0.16% than PM6:BTP-eC9 based ones (17.08%+/- 0.11%). Moreover, the PM6:L8-BO+ based OSC presents an impressive PCE of 19.14%. It demonstrates that introducing AN is an efficient method to increase the tau for prolonged LD, boosting PCEs of OSCs. (sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(tau)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(LD)(sic), (sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(OSC)(sic)(sic)(sic)(sic)(sic)(sic)(PCE)(sic)(sic)(sic). (sic)(sic)(sic)(sic)(AN)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic): (sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)tau. (sic)(sic)AN(sic)(sic)(sic)(sic)(sic)PM6:BTP-eC9+(sic)(sic)(sic)(sic)(sic)(sic)(sic), (sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)tau(sic)(sic)(sic)1.48 mu s, (sic)(sic)(sic)(sic)LD(sic)(sic)(sic). (sic)PM6:BTP-eC9(sic)(sic), (sic)(sic)(sic)LD(sic)(sic)(sic)PM6:BTP-eC9+(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic),(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic). (sic)(sic), (sic)PM6:BTP-eC9(sic)(sic) ((sic)(sic)(sic)17.08% +/- 0.11%)(sic)(sic), (sic)(sic)PM6:BTP-eC9+(sic)(sic)(sic)(sic)(sic)(sic)(sic)(18.41%+/- 0.16%). (sic)(sic), (sic)(sic)PM6:L8-BO+(sic)(sic)(sic)(sic)(sic)(sic)(sic)19.14%. (sic)(sic)(sic)(sic), (sic)(sic)AN(sic)(sic)(sic)(sic)(sic)(sic)(sic)tau(sic)(sic)LD(sic)(sic)(sic), (sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic).