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Updated April 26, 2018

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Characterization of the photoelectrode/electrolyte interface with first principles modeling and in situ measurement

M. Sato, K. Fujii (RIKEN), and M. Sugiyama

Microscopic understanding and characterization of semiconductor/electrolyte interface structures are essential for tailoring the properties of photoelectrochemical reactions. In this study, we reveal the semiconductor/electrolyte interface structure with the aid of first principles calculations and in situ measurements. Even though, first principles calculation has become a powerful tool for materials design in many fields, theoretical design of photocatalysts and photoelectrodes has met with limited success. To overcome this problem, we investigate from first-principles, the carrier accumulation processes at the semiconductor/electrolyte interface, which, though usually disregarded, has a large impact on photoelectrochemical reactions. In addition, together with in situ measurements using infra-red or X-rays, the semiconductor/electrolyte interface structure is studied. In the case of GaN/water interface, both atomistic simulations and FTNIR experiments indicate that the interface structure changes under UV radiation. These results underline the importance of the surface-charge-sensitive modeling approach.

Fig. 1 (left) Schematics of photoelectrode/electrolyte interface: (a) geometric structure, (b) electronic structure, and (c) charge transfer and chemical reactions. (right) Typical electronic structure of GaN surface.