Strain and stress effects on single crystal-supported titania and related nanostructures

Abstract

Abstract The properties of materials can be altered by introducing strain. For instance, the critical temperature of superconductors has been raised as has the Curie temperature of ferroelectric materials. As TiO2 is the most studied single crystal metal oxide, it is highly desirable to understand how strain might be used to tune its properties. Theoretical calculations indicate that the band gap of anatase TiO2 may be lowered, which would remove one of the roadblocks to its wider use as a photocatalyst. Surface defects on rutile TiO2 are responsible for a large part of its reactivity and the nature of these may also be affected by strain according to calculations. In this review, the introduction of strain and its effect on reactivity will be examined. The strain in the most part arises from lattice mismatch in the growth of TiOx films on various substrates although cases where TiO2 is the substrate are also included as is the implantation of Ar clusters in the subsurface of TiO2.