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Please use this identifier to cite or link to this item: http://hdl.handle.net/123456789/368

Title: Photoreactivity of ZnO nanoparticles in visible light: Effect of surface states on electron transfer reaction
Authors: Baruah, Sunandan
Sinha, Sudarson Sekhar
Ghosh, Barnali
Pal, Samir Kumar
Raychaudhuri, A K
Dutta, Joydeep
Issue Date: 2009
Publisher: Journal of Applied Physics
Citation: Sunandan Baruah, Sudarson Sekhar Sinha, Barnali Ghosh, Samir Kumar Pal, A. K. Raychaudhuri, and J. Dutta, Photoreactivity of ZnO nano particles in visible light: Effect of surface states on electron transfer, Journal of Applied Physics, 2009, 105, 074308
Abstract: Wide band gap metal oxide semiconductors such as zinc oxide ZnO show visible band photolysis that has been employed, among others, to degrade harmful organic contaminants into harmless mineral acids. Metal oxides show enhanced photocatalytic activity with the increase in electronic defects in the crystallites. By introducing defects into the crystal lattice of ZnO nanoparticles, we observe a redshift in the optical absorption shifting from the ultraviolet region to the visible region 400–700 nm , which is due to the creation of intermediate defect states that inhibit the electron hole recombination process. The defects were introduced by fast nucleation and growth of the nanoparticles by rapid heating using microwave irradiation and subsequent quenching during the precipitation reaction. To elucidate the nature of the photodegradation process, picosecond resolved time correlated single photon count TCSPC spectroscopy was carried out to record the electronic transitions resulting from the de-excitation of the electrons to their stable states. Photodegradation and TCSPC studies showed that defect engineered ZnO nanoparticles obtained through fast crystallization during growth lead to a faster initial degradation rate of methylene blue as compared to the conventionally synthesized nanoparticles.
URI: http://hdl.handle.net/123456789/368
Appears in Collections:2009

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