The crystallinity and intermolecular interaction among small molecules are enhanced in order to achieve reasonable phase segregation between the donor and acceptor in all-small-molecule organic solar cells (ASM OSCs). By substituting an alkyl side chain with a chlorine (Cl) atom on the original benzodithiophene terthiophene rhodanine (BTR) molecule, the new small molecular donor, namely BTR-Cl, processes a more ordered liquid crystalline property, down-shifted molecular energy levels, and higher crystallinity. When blended with a non-fullerene acceptor Y6, which has a complementary absorption profile and well-matched energy levels but no liquid crystalline property, a prominent phase separation and optimal film morphology are obtained. As a result, a record-high power conversion efficiency (PCE) of 13.6% is achieved, taking a large step forward in ASM OSCs. Our results highlight the importance of crystallinity to phase separation, suggesting the great promise of liquid crystalline materials in OSCs.

小分子之间的结晶度和分子间相互作用得到增强，以便在全小分子有机太阳能电池（ASM OSC）中实现施主和受主之间的合理相分离。新的小分子供体BTR-Cl通过在原始苯并二噻吩三噻吩罗丹宁（BTR）分子上用氯（Cl）原子取代烷基侧链，从而处理了更有序的液晶性质，分子能级向下移动，和更高的结晶度。当与非富勒烯受体Y6共混时，该受体具有互补的吸收曲线和良好匹配的能级，但没有液晶性能，可获得显着的相分离和最佳的膜形态。结果，实现了创纪录的13.6％的高功率转换效率（PCE），在ASM OSC中迈出了一大步。我们的结果突出了结晶度对相分离的重要性，表明了OSC中液晶材料的巨大前景。