(208h) Electrostatic Properties of Semiconductor-Electrolyte Interface with Surface Charge Regulation

The interface between a semiconductor material and an
electrolyte solution has interesting and complex electrostatic properties. Its behavior
depends on the density of mobile charge carriers that are present in both
phases as well as on the surface chemistry at the interface through surface
charge regulation. The latter is driven by chemical equilibria involving the
immobile surface groups and the potential determining ions in the electrolyte
solution. All these lead to an electrostatic potential distribution that
propagates in such a way that the electrolyte and the semiconductor are
dependent on each other. Any variation in the charge density in one phase will
lead to a response in the other. This has significant implications on the
physical properties of a single semiconductor-electrolyte interface and on the
electrostatic interactions between semiconductor particles suspended in
electrolyte solutions. We show that doped nanocolloids are less stable in
comparison with pure dielectric particles with identical surface chemistry. The
Figure shows the electrostatic potential distribution inside and outside two
interacting semiconductor spherical colloids. Our results have potential
implications for applications such as sensing and detection, catalysis, and self-assembly
of semiconductor nanoparticles.