Polyaniline on crystalline silicon heterojunction solar cells

Organic/inorganic heterojunction solar cells were fabricated on the (100) face of n-type silicon crystals using acid-doped polyaniline (PANI) with widely varying conductivities. For films with conductivities below 10(-1) S/cm, the open-circuit voltage V-OC increases with increasing film conductivity as expected when V-OC is limited by the work function of the film. Extrapolation of these results to the higher conductivity films indicates that PANI could support V-OC of 0.7 V or larger. V-OC measurements for the cells with higher conductivity PANI saturated at 0.51 V. We speculate that uncontrolled surface states at the PANI/Si interface are reducing these values. (c) 2007 American Institute of Physics.