Interaction of Stern layer and domain structure on photochemistry of lead-zirconate-titanate

Perovskite ferroelectric materials such as PZT have long been known to have wideband semiconducting properties. It has also been found that they have interesting spatially controllable surface photochemical effects that are not seen in 'normal' semiconductors. This has led to their being studied as possible tools in areas such as metal salt reduction and oxidation for nanoparticle growth. This paper discusses the effects of incident photon energy on the reduction of Ag⁰ onto PZT(30/70) surfaces with particular emphasis on the part played by energy band bending and the Stern layer. It was found that for increasing photon energy between 4.4 and 5.0 eV both the [1 1 1] and the [1 0 0] orientations of PZT followed a similar trend in that the average Ag ⁰ cluster cross-sectional area increased by a ratio of ca 1.6 to 1. This increase was put down to the higher energy photons exciting more electrons from deeper in the density of states for the material allowing a greater reduction rate of Ag⁺ at the surface.