Organic photovoltaic performance and structural relationship of non-fullerene small molecule acceptors based on a tetraarylphenazine core and perylene diimide

Here we report a pair of perylene diimide (PDI) non-fullerene small molecular acceptors (SMAs) based on a phenazine core with either benzene or thiophene linkers. Our main design rationale is to introduce a relatively parallel orientation for PDI units by connecting two PDI units on the same side of the phenazine core. While we find that the phenazine core can introduce a parallel intramolecular orientation, it is also found that the choice of linker units also has a major influence on the molecular geometry. As a result, the two SMAs, TPPhen-4PDI and TTPhen-4PDI, exhibit very different performances. The SMA with benzene linkers, TPPhen-4PDI, can achieve a power conversion efficiency of up to 8.3%. The performance difference was also supported by a significant difference in charge mobility and GIWAXS analysis. Our work provides some important understanding on the linker influence of structural properties, and guidelines to the design of high performance PDI-based SMAs.

Automated summary

In this study, we report a pair of perylene diimide (PDI) non-fullerene small molecular acceptors (SMAs) based on a phenazine core with either benzene or thiophene linkers. We introduced a relatively parallel orientation for PDI units by connecting two PDI units on the same side of the phenazine core. Our work provides important understanding on the linker influence of structural properties and guidelines for the design of high performance PDI-based SMAs.