Fabrication of N-doped TiO2 coatings on nanoporous Si nanopillar arrays through biomimetic layer by layer mineralization

Abstract

Si/N-doped TiO₂ core/shell nanopillar arrays with a nanoporous structure are fabricated through a simple protein-mediated TiO₂ deposition process. The Si nanopillar arrays are used as templates and alternatively immersed in aqueous solutions of catalytic molecules (protamine, PA) and the titania precursor (titanium(IV) bis(ammonium lactato)dihydroxide, Ti-BALDH) for the layer by layer mineralization of a PA/TiO₂ coating. After a subsequent calcination, a N-doped TiO₂ layer is formed, and its thickness could be controlled by varying the cycles of deposition. Moreover, the nanoporous structure of the Si nanopillars strongly affects the formation of the TiO₂ layer. The obtained Si/TiO₂ nanocomposites show significantly improved solar absorption compared with commercially purchased TiO₂ nanoparticles.