Critical interfaces in new solar cell materials: organic heterojunctions and heterojunctions involving semiconductor nanoparticles

The heterojunctions formed between different organic dyes (O/O' heterojunctions), organic dyes with contacting oxide or metal electrodes (O/I heterojunctions), and semiconductor nanoparticles with organic host polymers and ligands (SC-NP/ O heterojunctions) must be understood and optimized in order to enhance the energy conversion efficiencies of photovoltaics using these materials as their active components. We have used combinations of UV-photoelectron spectroscopy, and X-ray photoelectron spectroscopy (UPS/XPS) in the characterization of representative heterojunctions, and extrapolate these studies to the optimization of new photovoltaic and photoelectrochemical energy conversion devices.