Current-voltage characteristics and energetics of coulombically bound charge carrier pairs (copper phthalocyanine and boron subphthalocyanine chloride donors, and a fullerene acceptor) at the heterojunction in organic semiconductor junctions.
New equation could advance research in solar cell materials
Scientists in the Nanophotonics Group, the University of Michigan, and Northwestern University have developed a ground-breaking equation for organic semiconductor junctions. Organic, or "plastic" electronics, are a relatively new technology with the prospect of providing ultracheap, lightweight, and flexible electronic applications such as organic solar cells. Their model is successfully applied to two archetype, planar heterojunction organic photovoltaic cells and results in an ideal diode equation that is analogous to the widely adopted Shockley Equation for traditional inorganic devices. Organic semiconductors are characterized by hopping transport on the nanoscale and tightly bound, localized exciton states as opposed to the delocalized nature of charge carriers in inorganic semiconductors. These results should have significant impact on both the understanding and further development of this exciting new class of solar cell.
N. C. Giebink et al., “Ideal diode equation for organic heterojunctions. I. Derivation and application” and “II. The role of polaron pair recombination,” Phys. Rev. B, 82, 155305 and 155306 (2010)