Femtosecond laser doping of TiO2 for photocatalysis

Presentation Date: 

Monday, January 24, 2011

Location: 

Photonics West (San Fransisco, CA)

Presentation Slides: 

We present a novel method for femtosecond-laser doping of titanium dioxide (TiO2) for enhanced absorptance in the visible electromagnetic spectrum. With a bandgap of 3.2 eV for the anatase crystalline phase, TiO2 most strongly absorbs in the UV range ( < 387 nm). However, doping with metals and nitrogen has been shown to create intermediate states in the bandgap, generating a new material for visible-light photocatalysis that has the potential for watersplitting. Using femtosecond laser doping techniques on bulk TiO2 in a gaseous environment, we produce laser-induced periodic surface structures. We compare how the surface morphology and optical properties vary with gas composition and laser parameters. In addition, we present compositional data from x-ray photoelectron and Raman spectroscopy and structural data from scanning electron microscopy. We also show the creation of oxygen deficiencies after raster scanning and investigate their role in altering absorptance. Our research presents an innovative approach using laser scanning techniques to alter the structure of the TiO2 crystal for solar harvesting.