Abstract
Luminescence characteristics and surface chemical changes of nanocrystalline Mn 2+ doped ZnAl 2 O 4 powder phosphors are presented. Stable green cathodoluminescence (CL) or photoluminescence (PL) with a maximum at ∼512 nm was observed when the powders were irradiated with a beam of high energy electrons or a monochromatic xenon lamp at room temperature. This green emission can be attributed to the 4 T 1 → 6 A 1 transitions of the Mn 2+ ion. Deconvoluted CL spectra resulted in two additional emission peaks at 539 and 573 nm that may be attributed to vibronic sideband and Mn 4+ emission, respectively. The luminescence decay of the Mn 2+ 512 nm emission under 457 nm excitation is single exponential with a lifetime of 5.20 ± 0.11 ms. Chemical changes on the surface of the ZnAl 2 O 4 :Mn 2+ phosphor during prolonged electron beam exposure were monitored using Auger electron spectroscopy. The X-ray photoelectron spectroscopy (XPS) was used to determine the chemical composition of the possible compounds formed on the surface as a result of the prolonged electron beam exposure. The XPS data suggest that the thermodynamically stable Al 2 O 3 layer was formed on the surface and is possibly contributing to the CL stability of ZnAl 2 O 4 :Mn phosphor.
Original language | English |
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Pages (from-to) | 3298-3306 |
Number of pages | 9 |
Journal | Applied Surface Science |
Volume | 257 |
Issue number | 8 |
DOIs | |
Publication status | Published - 1 Feb 2011 |
Externally published | Yes |
Keywords
- Auger electron spectroscopy
- Cathodoluminescence
- X-ray photoelectron spectroscopy
ASJC Scopus subject areas
- General Chemistry
- Condensed Matter Physics
- General Physics and Astronomy
- Surfaces and Interfaces
- Surfaces, Coatings and Films