Аннотация:We have designed a new medium bandgap non-fullerene small-moleculeacceptor consisting of an IDT donor core flanked with 2-(6-oxo-5,6-dihydro-4Hcyclopenta[c]-thiophene-4-ylidene) malononitrile (TC) acceptor terminal groups (IDTTC) and compared its optical and electrochemical properties with the IDT-IC acceptor.IDT-TC showed an absorption profile from 300 to 760 nm, and it has an optical bandgapof 1.65 eV and HOMO and LUMO energy levels of −5.55 and −3.83 eV, respectively. Incontrast to IDT-IC, IDT-TC has an upshifted LUMO energy level, which is advantageousfor achieving high open-circuit voltage. Moreover, IDT-TC showed higher crystallinity andhigh electron mobility than IDT-IC. Using a wide bandgap D−A copolymer P as thedonor, we compared the photovoltaic performance of IDT-TC, IDT-IC, and IDT-IC-Clnonfullerene acceptors (NFAs). Polymer solar cells (PSCs) using P: IDT-TC, P: IDT-IC,and P:IDT-IC-Cl active layers achieved a power conversion efficiency (PCE) of 14.26, 11.56, and 13.34%, respectively. As theabsorption profiles of IDT-IC-Cl and IDT-TC are complementary to each other, we have incorporated IDT-TC as the guestacceptor in the P: IDT-IC-Cl active layer to fabricate the ternary (P:IDT-TC: IDT-IC-Cl) PSC, demonstrating a PCE of 16.44%,which is significantly higher than that of the binary BHJ devices. The improvement in PCE for ternary PSCs is attributed to theefficient exploitation of excitons via energy transfer from IDT-TC to IDT-IC-Cl, suitable nanoscale phase separation, compactstacking distance, and more evenly distributed charge transport
