The non-fullerene acceptors (NFAs) employed in state-of-art organic photovoltaics (OPVs) often exhibit strong quadrupole moments which can strongly impact on material energetics. Herein, we show that changing the orientation of Y6, a prototypical NFA, from face-on to more edge-on by using different processing solvents causes a significant energetic shift of up to 210 meV. The impact of this energetic shift on OPV performance is investigated in both bilayer and bulk-heterojunction (BHJ) devices with PM6 polymer donor. The device electronic bandgap and the rate of non-geminate recombination are found to depend on the Y6 orientation in both bilayer and BHJ devices, attributed to the quadrupole moment-induced band bending. Analogous energetic shifts are also observed in other common polymer/NFA blends, which correlates well with NFA quadrupole moments. This work demonstrates the key impact of NFA quadruple moments and molecular orientation on material energetics and thereby on the efficiency of high-performance OPVs.

Using a combinatory blending strategy is demonstrated as a promising path for designing efficient organic solar cells (OSCs) by boosting the short‐circuit current density and fill factor. Herein, a high‐performance ternary all‐small molecule OSC (all‐SMOSCs) using a narrow‐bandgap alloy acceptor containing symmetric and asymmetric molecules (BTP‐eC9 and SSe‐NIC) and a wide‐bandgap small molecule donor MPhS‐C2 is reported. Introducing the synthesized SSe‐NIC into the MPhS‐C2:BTP‐eC9 host system can broaden the absorption spectrum, modulate energy offsets, and optimize the molecular packing of the host materials. After systematically optimizing the weight ratio of MPhS‐C2:BTP‐eC9:SSe‐NIC, a champion efficiency of 18.02% is achieved. Impressively, the ternary system not only delivered a broad composition tolerance with device efficiencies over 17% throughout the whole blend ratios, but also exhibited less non‐geminate recombination and energy loss, and better‐light‐soaking stability than the corresponding binary systems. This work promotes the development of high‐performance ternary all‐SMOSCs and heralds their brighter application prospects.

Designing new high-performance non-fullerene acceptors is the key driving force for the development of organic solar cells (OSCs). In this work, a new acceptor, BOEH-4Cl, was designed based on the...

To realize the application of organic solar cells (OSCs), an emphasis must be placed on reducing material cost, which is one of the golden triangle elements. One key strategy to...