LAUSR

Organic nanoparticle-based solar cells have drawn considerable attention due to its eco-friendly and environ-friendly fabrication procedure. However, these surfactant-stabilized nanoparticles suffer open circuit voltage loss due to charge trapping and reduced extraction rate at the polymer cathode interface. We investigated the origin of voltage loss and charge trapping in surfactant-stabilized nanoparticle-based devices. We fabricated efficient organic photovoltaic (OPV) devices from an aqueous dispersion of poly(3-hexylthiophene-2,5-diyl) (P3HT) and [6,6]-phenyl-C61-butyric acid methyl ester (PCBM) nanoparticles stabilized by anionic surfactants. We used AC impedance spectroscopy to understand the charge transport properties in the dark and in operando conditions. We demonstrate the charge transport properties as well as photocarrier dynamics of the nanoparticle-based OPVs and the bulk hetero-junction OPVs, are similar despite fundamental differences in their nanostructure morphology. This study emphasizes the possibility of fabricating highly efficient OPVs from organic nanoparticles by reducing surface defects and excess doping of the polymers.