Mesoporous Dye-sensitized Solar Cells Research Articles

Physical Chemical Principles of Photovoltaic Conversion with Nanoparticulate, Mesoporous Dye-Sensitized Solar Cells

We review the status of the understanding of dye-sensitized solar cells (DSSC), emphasizing clear physical models with predictive power, and discuss them in terms of the chemical and electrical potential distributions in the device. Before doing so, we place the DSSC in the overall picture of photovoltaic energy converters, reiterating the fundamental common basis of all photovoltaic systems as well as their most important differences.

Nature of Photovoltaic Action in Dye-Sensitized Solar Cells

We explain the cause for the photocurrent and photovoltage in nanocrystalline, mesoporous dye-sensitized solar cells, in terms of the separation, recombination, and transport of electronic charge as well as in terms of electron energetics. On the basis of available experimental data, we confirm that the basic cause for the photovoltage is the change in the electron concentration in the nanocrystalline electron conductor that results from photoinduced charge injection from the dye. The maximum photovoltage is given by the difference in electron energies between the redox level and the bottom of the electron conductor's conduction band, rather than by any difference in electrical potential in the cell, in the dark. Charge separation occurs because of the energetic and entropic driving forces that exist at the dye/electron conductor interface, with charge transport aided by such driving forces at the electron conductor/contact interface. The mesoporosity and nanocrystallinity of the semiconductor are importa...