A method of making a bulk heterojunction organic photovoltaic cell by glancing angle deposition. As the disclosed method relies on a trajectory of incident vapor flux that is not parallel to the substrate normal, micro and nano-scale columnar structures of thin films can be grown on the substrate. There is also disclosed a method of forming a donor-acceptor heterojunction by depositing at least one additional organic material over the columnar structures.
STATEMENT REGARDING FEDERALLY SPONSORED RESEARCH
 This invention was made with U.S. Government support under Contract No. DE-FG36-08G018022 awarded by U.S. Department of Energy, National Renewable Energy Laboratory. The government has certain rights in this invention.