Organic/inorganic heterojunction solar cells were fabricated on the (100) face of nn-type silicon crystals using acid-doped polyaniline (PANI) with widely varying conductivities. For films with conductivities below 10−1S/cm10−, the open-circuit voltage VOCV increases with increasing film conductivity as expected when VOCV is limited by the work function of the film. Extrapolation of these results to the higher conductivity films indicates that PANI could support VOCV of 0.7V0.7 or larger. VOCV measurements for the cells with higher conductivity PANI saturated at 0.51V0.51. We speculate that uncontrolled surface states at the PANI/Si interface are reducing these values.

This research has been supported by the National Renewable Energy Laboratory (subcontract No. NDJ-2-30630-24) and the Syracuse Center of Excellence in Environmental and Energy Systems. We thank Bernhard Wessling (Ormecon, GmbH) for a critical reading of the manuscript and for samples of Ormecon’s polyaniline dispersions, Qi Wang (National Renewable Energy Laboratory) and Dmitry Poplavskyy (Innovalight, Inc.) for discussions, and Manfred Schmidt (Hahn-Meitner Institut) for c-Sic wafers.