Titania nanostructures electronic and optical response

TiO2 nanomaterials are object of strong research interest for their promising performances in photocatalysis, photovoltaics and gas sensing. Investigating the microscopic nature of their opto-electronic properties is a fundamental prerequisite for rationalizing experimental data and improving devices performances. First-principle excited states methods, based on Many-Body Perturbation Theory on top of Density Functional Theory calculations, provide a reliable tool to identify, explain and predict specific behaviour related to the electronic and optical properties of nanostructures, which can be hidden in the experimental processes. Examples of titania nanostructures (clusters, reconstructed surfaces, and nanosheets, also related to nanotubes and nanowires) are analyzed, and the relationship among structure and electro-optical behaviour is clearly highlighted. Strong excitonic effects, which allow a correct interpretation of the photoexcited processes, are observed in all the considered nanostructures.