Abstract
We demonstrate the halogen-free solvent fabrication of “quasi-bilayer” inverted organic photovoltaic devices. The inferior solubility of pristine fullerene in non-halogenated solvents is utilized to control the interpenetration of upper polymeric donor layers with bottom fullerene layers. Island-like nano-morphologies are revealed by SEM and TEM. Correlation between device performance and thin-film nano-morphology is observed. High efficiencies of up to 6.55% and 7.15% were observed for PBDTTT-C-T and PTB7 cells, respectively.