Studying the kinetics of fullerene agglomeration in ink solutions for organic photovoltaic devices

Fullerene nanoparticles are used in a wide range of applications including as electron acceptors in organic photovoltaics (OPV). The manufacturing of OPV devices relies on the use of solution processing methods such as spin-coating and spray coating and therefore, fullerenes need to have a reasonably high solubility in the processing solvent.Although the fullerenes PC61BM and PC71BM have been used almost interchangeably in the preparation of OPV devices, in a previous SESANS study we have demonstrated that PC71BM is fundamentally more soluble than PC61BM in the solvents commonly used in OPV. In this work we propose to study the kinetics of agglomeration of the fullerenes PC61BM and PC71BM in ink solutions with relevance for OPVs. The use of Larmor is requested in order to investigate the agglomeration behaviour of these materials using SESANS and SANS.