LAUSR

An A-D-A-type non-fullerene acceptor (NFA), PTTtID-Cl, featuring thieno[3,2-b]thieno[2''',3''':4'',5'']-pyrrolo[2'',3'':4',5']thieno[2',3':4,5]thieno-[2,3-d]pyrrole (DTPTt) as the electron-rich core and 2-(5,6-dichloro-3-oxo-2,3-dihydro-1H-inden-1-ylidene)malononitrile (ID-Cl) as the peripheral electron-deficient terminal group was synthesized and characterized. PTTtID-Cl exhibits strong absorption range of 700-850 nm in CHCl3 and red-shifted absorption centered at 881 nm in thin film. The near infrared (NIR)-absorption PTTtID-Cl was combined with a low bandgap polymer donor PTB7-Th to achieve the binary and semi-transparent (OPV) with the PCE of 8.9% and 7.7% (with an average visible transmittance (AVT) of 16.7%), respectively. The ternary device with the ratio of PM7:PTTtID-Cl:IT-4F = 1:0.15:0.85 (w/w) achieved Jsc of 19.46 mA cm-2, Voc of 0.87 V, and FF of 71.2%, giving the PCE up to 12.0%. In addition, employing the Ag/ITO/Ag microcavity structure, semi-transparent colorful binary OPVs display superior transparency of 27.9% at 427 nm and 22.7% at 536 nm for blue and green device, respectively, were achieved. The semi-transparent colorful device based on optimized ternary blend gave PCE of 8.7%, 8.4% and 9.1% for blue, green and red devices, respectively. These results indicate the promising potential of PTTtID-Cl as NIR-absorption NFA for applications in semi-transparent colorful binary and ternary OPVs.