Bulk Heterojunction Solar Cell (IMAGE) DOE/Oak Ridge National Laboratory Caption Fullerenes appear as small silver spheres spread consistently throughout a network of small molecules, or polymers, in this schematic illustration of the morphology of a BHJ film with solvent additives. Credit Oak Ridge National Laboratory Usage Restrictions Credit: ORNL License Licensed content Disclaimer: AAAS and EurekAlert! are not responsible for the accuracy of news releases posted to EurekAlert! by contributing institutions or for the use of any information through the EurekAlert system.