Publication date: 8th January 2019
Organic solar cells (OCSs) based on non-fullerene acceptors offer a potential alternative to fullerene conterparts. Although a lot of non-fullerene OSCs have been reported with effecienceies exceeding 10% mainly based on small molecule acceptors, there has not been much reports on the differences between small molecule and polymers acceptors in terms of film formation in bulk heterojunction blends and their relation to device performance.
Here, we investigate the differences between polymer and small molecule acceptors in terms of solar cell performance. For this, we combine a PCE11 polymer as the donor material with acceptors based on perylene diimide cores.
In addition to the performance of planar and bulk heterojunction devices, we study the film formation during spin coating of different blends in real time using state of the art in-situ optical spectroscopy measurements at different temperatures.
We show that the aggregation behavior of the blends depends on both the type of acceptor used as well as the temperature of spin coating; this is related to the solar cell performance.