NEW APPROACHES TO SOLAR-ENERGY CONVERSION USING SI LIQUID JUNCTIONS/

New data are presented on efficient Si/liquid junction photoelectroche mical energy conversion devices. Additional information on the interfa cial energetics, charge transfer kinetics, and stabilization factors o f these interfaces has been obtained using a variety of chemical and e lectrical methods. Transconductance and Mott-Schottky measurements of the barrier height of n-Si/CH3OH-Me(2)Fc(+/0) contacts have demonstrat ed that the Si is in strong inversion, with a barrier height of 1.0 eV . Qualitative evidence for the validity of Marcus-Gerischer theory was obtained in measurements of the stabilization ratio as a function of the reorganization energy of the stabilizing redox agent. In addition, a new type of photoelectrochemical cell, in which charge carriers are collected primarily using diffusion gradients as opposed to drift, ha s shown high efficiency and unpinned electrical junction behavior in c ontact with various redox couples.