Determination of the solubility parameters and agglomeration behaviour of conjugated polymers via a binary solvent gradient method

The efficiency of lab-based, small-area organic photovoltaic (OPV) devices has steadily increased over the last 15 years, increasing from <5% in 2005 to >16% in 2019. The manufacturing of OPV devices relies on the use of solution processing methods such as spin-coating, spray coating and inkjet printing. Therefore, to be processed during device manufacture, conjugated polymers need to have a reasonably high solubility in a given solvent. We have developed a new method to investigate solubility in such materials using a combination of SANS and SESANS which will use in this study. This allows us to investigate the solubility in dark opaque solutions, these are not accessible to traditional UV and visible absorption methods. By studying the solubility we will be able to determine the optimum conjugated polymer types that can be utilised in solar cell fabrication.