The response of the open-circuit photovoltage, Voc, has been investigated with regard to changes in the minority carrier diffusion length, majority carrier density, short-circuit photocurrent density, and cell temperature of n-Si/CH3OH junctions. The reaction kinetics are observed to be first order in dopant density, minority carrier diffusion length, and photocurrent density. The activation barrier for carrier recombination, obtained from plots of Voc vs. temperature, is 1.15 ± 0.05 eV. An optimum dopant density for maximum Voc is observed, and this is consistent with bulk lifetime measurements on similarly doped Si samples. The reaction kinetics are not sensitive to the concentration of redox species (at constant electrochemical potential), indicating minimal recombination losses due to poor interfacial charge transport rates. Voc values for optimally doped systems (Voc = 670 mV for 0.015 Ω-cm n-Si samples at 20 mA/cm2 photocurrent densities) represent the highest photovoltages obtained to date for any n-Si-based surface barrier device. Surface recombination velocity measurements at the n-Si/CH3OH interface have been performed, and correlations between the surface recombination rate and the improvement in current-voltage properties have been investigated.
|Number of pages||7|
|Journal||Journal of the American Chemical Society|
|Publication status||Published - 1986|
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