Laser-assisted synthesis of ultra-small anatase TiO 2 nanoparticles

M. Amin, J. Tomko, J. J. Naddeo, R. Jimenez, D. M. Bubb, M. Steiner, J. Fitz-Gerald, S. M. O'Malley

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Abstract

Titanium dioxide is one of the most important materials today in terms of green technology. In this work, we synthesis ultra-small titanium dioxide nanoparticles (NPs) via a two step process involving infrared laser ablation of a bulk titanium target in DDI water and subsequent irradiation of the colloidal solution with visible light. The as-prepared NPs contain defect states related to oxygen vacancies which lead to visible light sensitization as observed by photodegradation of methylene blue. Irradiation of the colloidal TiO 2 solution, with a 532 nm picosecond laser, lead to fragmentation and ultimate formation of ultra-small (<3 nm) anatase particles. Shadowgraph was utilized to capture shockwave and cavitation bubble propagation during both the ablation and fragmentation processes. High-frequency ripples within the primary shockwave are identified as coming from laser induced stress-wave reflections within the metal target. A blueshift of the bandgap, for the ultra-small NPs, is explained by quantum confinement effects and rationalized using the Brus model.

Original languageEnglish (US)
Pages (from-to)30-37
Number of pages8
JournalApplied Surface Science
Volume348
DOIs
StatePublished - Sep 1 2015

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All Science Journal Classification (ASJC) codes

  • Chemistry(all)
  • Condensed Matter Physics
  • Physics and Astronomy(all)
  • Surfaces and Interfaces
  • Surfaces, Coatings and Films

Keywords

  • Fragmentation
  • Laser synthesis
  • Photocatalysis
  • Shockwave propagation
  • Titanium dioxide nanoparticles

Cite this

Amin, M., Tomko, J., Naddeo, J. J., Jimenez, R., Bubb, D. M., Steiner, M., Fitz-Gerald, J., & O'Malley, S. M. (2015). Laser-assisted synthesis of ultra-small anatase TiO 2 nanoparticles Applied Surface Science, 348, 30-37. https://doi.org/10.1016/j.apsusc.2014.12.191