Towards High-Performance Organic Solar Cells Deposited from Nanoparticle Dispersions

Record power conversion efficiencies of organic solar cells are most often achieved upon deposition from toxic solvents such as chloroform. Yet, organic solar cells can reach their full potential only if high performance is coupled with eco-friendly processing of organic semiconductors instead. Recent reports have demonstrated that organic nanoparticle dispersions are a viable route to combine sustainable production with maintaining high power conversion efficiencies. As of today, omitting surfactants for the stabilization of the dispersions appears mandatory when targeting highest solar cells performance since surfactants would remain in the solar cell and affect the formation of the delicate bulk-heterojunction. When using electrostatic stabilization instead, so far, only selected donors can be combined with selected absorbers in selected dispersion media to produce stable nanoparticle dispersions. In this work, design criteria will be discussed how to select the components of the dispersion. The role of the ionization potential of donors, the miscibility of donors and acceptors as well as the properties of the dispersion medium are elucidated. Stabilization concepts of the dispersions are compared for their process viability.<br/><br/>[F. Manger et al., Adv. Energy Mater. 2023, 2202820; F. Manger et al., Adv. Funct. Mater. 2022, 2202566; P. Marlow et al., Nanoscale 2022, 14, 5569-5578]