Tetraphenylethylene Vs Triphenylethylene Core-Based Perylene Diimide Acceptor for Non-Fullerene Organic Solar Cells

The ethylene fused PDI oligomers, especially for the dimer (PDI2), have emerged as alternative building blocks to the parent PDI in constructing NFAs owing to their outstanding optoelectronic properties, twisted configurations as well as concise gram-scale synthesis. In this work, a non-fullerene acceptor (NFA) based on tetraphenylethylene (TPE) core flanked with four PDI2 units, coded as TPE-4PDI2, was designed and synthesized. The analogue (TriPE-3PDI2) which consists of triphenylethylene (TriPE) and three PDI2 panels was synthesized for comparison. OSCs based on TPE-4PDI2 show a best PCE of 7.10%, which is much higher than that of TriPE-3PDI2 based ones. Moreover, this PCE is also higher than that of TPE-4PDI based devices (5.53%). To the best of our knowledge, the PCE of 7.10% is among the highest values for TPE-cored NFAs based OSCs. These results indicate that PDI2 is a promising building block for constructing high performance NFAs. And this work provides a facile and effective molecule-designing method to promote the PCE of PDI based non-fullerene OSCs.