Fabrication of Solar Cells via an Aqueous Process
Organic photovoltaics — Aqueous-based fabrication

Once the nanoparticle suspensions have been obtained, the next step is to form a thin film capable of absorbing sufficient light, generating charges, and transporting them. To do this, the film must be uniform, have a thickness between 100 nm and 300 nm, and exhibit a morphology suitable for efficient charge transport and low leakage currents.

When forming an active layer from an organic solvent solution (chloroform, dichlorobenzene, o-xylene, etc.), the low polarity of these solvents allows for good wettability on commonly used surfaces. In fact, the vast majority of transport layers have a hydrophobic surface and are therefore compatible with nonpolar solvents, which is not the case with water. Consequently, one...