Photochromic silver nanoparticles fabricated by sputter deposition
- Department of Physics, Kenyatta University, P.O. Box 43844, Nairobi (Kenya)
In this study a simple route to preparing photochromic silver nanoparticles in a TiO{sub 2} matrix is presented, which is based upon sputtering and subsequent annealing. The formation of silver nanoparticles with sizes of some tens of nanometers is confirmed by x-ray diffraction and transmission electron microscopy. The inhomogeneously broadened particle-plasmon resonance of the nanoparticle ensemble leads to a broad optical-absorption band, whose spectral profile can be tuned by varying the silver load and the annealing temperature. Multicolor photochromic behavior of this Ag-TiO{sub 2} system upon irradiation with laser light is demonstrated and discussed in terms of a particle-plasmon-assisted electron transfer from the silver nanoparticles to TiO{sub 2} and subsequent trapping by adsorbed molecular oxygen. The electron depletion in the nanoparticles reduces the light absorption at the wavelength of irradiation. A gradual recovery of the absorption band is observed after irradiation, which is explained with a slow thermal release of electrons from the oxygen trapping centers and subsequent capture into the nanoparticles. The recovery can be accelerated by ultraviolet irradiation; the explanation for this observation is that electrons photoexcited in the TiO{sub 2} are captured into the nanoparticles and restore the absorption band.
- OSTI ID:
- 20713928
- Journal Information:
- Journal of Applied Physics, Vol. 97, Issue 9; Other Information: DOI: 10.1063/1.1888044; (c) 2005 American Institute of Physics; Country of input: International Atomic Energy Agency (IAEA); ISSN 0021-8979
- Country of Publication:
- United States
- Language:
- English
Similar Records
Silver decorated titanate/titania nanostructures for efficient solar driven photocatalysis
Synthesis of photochromic nanoparticles and determination of the mechanism of photochromism