Nanostructured and Photoelectrochemical Systems for Solar Photon Conversion

Characterization of photoelectrochemical cells for water splitting by electrochemical impedance spectroscopy

“…The photoelectrochemical water-splitting cell consists of a photoelectrode (semiconductor) that absorbs photons with sufficient energy to inject electrons from the valence to the conduction band of the semiconductor, creating electron-hole pairs. Holes oxidize water in the semiconductor surface, while electrons percolate through the semiconductor layer and reach the counter-electrode, via the external circuit, to promote water reduction at its surface [2,15]. The cycle is then closed when the electrolyte anions generated at the counterelectrode diffuse back to the surface of the semiconductor to recombine with holes.…”

Transient phenomenological modeling of photoelectrochemical cells for water splitting – Application to undoped hematite electrodes

“…In fact, the efficiency of the oxidation process occurring at the semiconductor can be limited by several competing electron loss pathways: bulk recombination via bandgap states or direct electron loss to holes in the valence band; surface recombination; electron loss from the conduction band; photocorrosion of the semiconductor; and dissolution reactions. The last two processes are responsible for the degradation of the electrode and for the consequent stability problems [28]. Fig.…”

Modeling, simulation and design of dye sensitized solar cells

“…Because the electrolyte is present throughout all the porous structure of the semiconductor, the recombination reaction is affected by the photoelectrode thickness, iodide concentration, dye structure and others. [6][7][8][9] The average electron diffusion coefficients in anatase TiO 2 ranges between 10 -4 to 10 In this work a dynamic phenomenological model proposed initially by Andrade et al 24 is used to describe the quantitatively effect that transport and recombination have in the performance of the solar cell, and the influence that this has in its design. The model is used to predict the influence of the recombination reaction rate constants (k r ) and diffusion coefficients (D eff ) in the V oc and J sc , considering linear or non-linear recombination reaction.…”