Low-bandgap nonfullerene acceptor based on thieno[3,2-b]indole core for highly efficient binary and ternary organic solar cells

• A novel electron-donating unit thieno[3,2- b ]indole is used as a core for acceptor. The binary PM6:TIT-2FIC solar cells have achieved decent PCEs of 13.00%. ternary PM6:TIT-2FIC:Y6 exhibited increased 17.22%. new acceptor TIT-2FIC presents promising performance and good compatibility. low-bandgap nonfullerene (NFA) based on ]indole-thiophenes has been developed. Compared with the analogue NFAs DTC(4Ph)-4FIC IT-4F, remarkably red-shifted absorption, up-shifted HOMO energy level. In addition, showed interesting universal miscibility donors nonfluorinated PBDB-T fluorinated PM6, therefore corresponding organic power conversion efficiencies (PCEs) 11.80% 13.00%, respectively, which are higher compared to counterpart IT-4F cells. Furthermore, cell pronounced high PCE 17.22%, being significantly improved from that 16.04% PM6:Y6 cell. Similar improvement in 13.41% 14.46% was also observed PM6:TIT-2FIC:IT-4F third component. These results indicated universally applicable an or polymer donor materials both