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Herein, a novel green emitting long-persistent Sr {sub 3} SiAl {sub 4} O {sub 11}: Eu {sup 2+}/Dy {sup 3+} phosphor was synthesized in a single phase form using facile solid state reaction method under the reducing atmosphere of 10% H {sub 2} and 90% N {sub 2}. The resulting phosphor exhibits hyper-sensitive strong broad green emission, peaking at 510 nm upon 340 nm excitation wavelength, which is attributed to the 4f {sup 6} 5d {sup 1}-4f {sup 7} transitions of emission center of europium (Eu {sup 2+}) ions. Moreover, the incorporation of dysprosium (Dy {sup 3+}) ions, which act as effective hole trap centers with appropriate depth, largely enhances the photoluminescence characteristics and greatly improves the persistent intense luminescence behavior of Sr {sub 3} SiAl {sub 4} O {sub 11}: Eu {sup 2+}/Dy {sup 3+} phosphor under ultraviolet (UV) excitation. In addition, with the optimum doping concentration and sufficient UV excitation time period, the as-synthesized phosphor can be persisted afterglow for time duration∼ 4 h with maximum luminescence intensity. Thus, these results suggest that this phosphor could be expected as an ultimate choice for next generation advanced luminescent materials in security applications such as latent finger-marks detection, photo-masking induced phosphorescent images, and security code detection.
Publication date: 
28 Jun 2015

Bipin Kumar Gupta, Arun Kumar, Pawan Kumar, Jaya Dwivedi, GN Pandey, Garima Kedawat

Biblio References: 
Volume: 117 Issue: 24
Journal of Applied Physics