Ternary organic solar cells (OSCs) have received extensive attention for improving the power conversion efficiency (PCE) of organic photovoltaics (OPVs). In this work, a novel donor material (ECTBD) consisting of benzodithiophene (BDT) central electron donor unit was developed and synthesized. The small molecular donor has the same central unit as PM6. The addition of ECTBD into PM6:Y6 system could improve the morphology of active blend layer. In addition, ECTBD showed good morphologically compatibility when blending with PM6:Y6 host, resulting in the improvement of fill factor and current density. As a result, the ternary devices based on PM6:ECTBD:Y6 ternary system achieved a highest PCE of 16.51% with fill factor of 76.24%, which was much higher than that of the binary devices (15.7%). Overall, this work provided an effective strategy to fabricate highly efficient ternary organic solar cells through design of the novel small molecular donor as the third component.

三元有机太阳能电池（OSC）已被广泛关注，以提高有机光伏（OPV）的功率转换效率（PCE）。在这项工作中，开发并合成了由苯并二噻吩（BDT）中心电子供体单元组成的新型供体材料（ECTBD）。小分子供体的中心单元与PM6相同。在PM6：Y6系统中添加ECTBD可以改善活性共混物层的形态。此外，ECTBD与PM6：Y6基质共混时显示出良好的形态相容性，从而改善了填充因子和电流密度。结果，基于PM6：ECTBD：Y6三元系统的三元设备的PCE最高，为16.51％，填充因子为76.24％，远高于二元设备的15.7％。总体，