L8-BO (CAS number 2668341-40-8) has a similar structure to the highly efficient Y6 non-fullerene acceptor with a fused thienothienopyrrolo-thienothienoindole (TTP-TTI) core. The only difference between L8-BO and Y6 is that L8-BO has two butyloctyl side chains attached to the core while Y6 has two undecyl side chains. The branched 2-butyloctyl side chains show great improvement in film while comparing with Y6 with better structural order to achieve an optimized, multi-length-scale film morphology. High carrier generation, low charge recombination rates and balanced charge transport can be expected.
It has been reported that single-junction non-fullerene polymer solar cells with L8-BO as the acceptor and PBDB-T-2F (PM6) as the polymer has achieved photo conversion efficiency (PCE) over 18% with the following device structure.
Device structure: ITO/PEDOT:PSS/PM6:L8-BO (1:1.2)/PNDIT-F3N/Ag