A large-area module (active area > 20 cm 2 ) with a power conversion efficiency (PCE) of 10.4% (certified at 10.1%) using a non-fullerene blend was demonstrated, which is by far the highest PCE reported to date. The same module also delivers a power of 40 mW/cm 2 (PCE 22%) under indoor lighting. Equally important, PCEs of 12%-14% were achieved for blends processed in ambient and/or without halogenated solvent.

In this research, a haptacyclic carbazole-based dithienocyclopentacarbazole (DTCC) ladder-type structure was formylated to couple with two 1,1-dicyanomethylene-3-indanone (IC) moieties, forming a new nonfullerene acceptor DTCCIC-C17 using a bulky branched 1-octylnonayl side chain at the nitrogen of the embedded carbazole and four 4-octylphenyl groups at the sp-carbon bridges. The rigid and coplanar main-chain backbone of the DTCC core provides a broad light-absorbing window and a higher-lying LUMO energy level, whereas the bulky flanked side chains reduce intermolecular interactions, making DTCCIC-C17 amorphous with excellent solution processability. The DTCCIC-C17 as an acceptor is combined with a medium band gap polymer poly[(2,6-(4,8-bis(5-(2-ethylhexyl)thiophen-2-yl)-benzo[1,2-b:4,5-b']dithiophene))-alt-(5,5-(1',3'-di-2-thienyl-5',7'-bis(2-ethylhexyl)benzo[1',2'-c:4',5'-c']dithiophene-4,8-dione))] (PBDB-T) as the donor in the active layer to obtain suitable highest occupied molecular orbital/lowest unoccupied molecular orbital energy alignments and complimentary absorption. The devices with an inverted configuration (ITO/ZnO/active layer/MoO/Ag) without using an aqueous poly(3,4-ethylenedioxythiophene) polystyrene sulfonate layer were fabricated for better device stability. When the diiodooctane-treated PBDB-T:DTCCIC-C17 active layer was thermally annealed at 50 °C for 10 min, the device achieved the highest efficiency of 9.48% with a high V of 0.98 V, a J of 14.27 mA cm, and an FF of 0.68.

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An A−D−A oligomer, DTS(F 2 BT) 2 , was synthesized; its structural evolution was studied with DSC, POM, 2D-WAXD, and in-situ GI-XRD. The structural evolution of DTS(F 2 BT) 2 is stepwise and kinetically slow. Both rapid drying and the presence of PC 71 BM trapped DTS(F 2 BT) 2 in a less ordered nematic (N) phase. PDMS-assisted crystallization enabled a pristine DTS(F 2 BT) 2 thin film to attain a more ordered equilibrium phase, and enhanced the OFET mobility of DTS(F 2 BT) 2 . In OPV devices, DIO additive drove the DTS(F 2 BT) 2 domains in the DTS(F 2 BT) 2 :PC 71 BM blended film from the N phase toward the equilibrium phase, and resulted in enhanced OPV performances. These results reveal the slow ordering process of the A−D−A oligomer, and the importance of monitoring the degree of structural evolution of the active thin films in organic optoelectronics.