Photoluminescence and Cathodoluminescence Properties of Nanocrystalline BaFCl:Sm³⁺ X-ray Storage Phosphor

Abstract

Nanocrystalline BaFCl:Sm3+ is an efficient photoluminescent X-ray storage phosphor. To gain a better understanding of the storage mechanism, the photoluminescence and cathodoluminescence properties of nanocrystalline BaFCl:Sm3+ before and after X-irradiation were investigated. The results were compared with those obtained for microcrystalline BaFCl:Sm3+ prepared by high-temperature sintering. Significant differences in the local coordination environment of Sm3+ ions between the two samples were revealed by comparing the photoluminescence spectra at 2 and 293 K. From the cathodoluminescence microanalysis, it follows that the Sm3+ ions in the as-prepared nanocrystalline BaFCl:Sm3+ are mainly located on or close to the surface of the nanoparticles, whereas those in the microcrystalline sample are distributed homogeneously throughout the microcrystallites. For nanocrystalline BaFCl:Sm3+, the X-irradiation-induced reduction of Sm3+ to Sm2+ ions and the photoionization of Sm2+ to Sm3+ ions during photobleaching were investigated by monitoring the photoluminescence intensities of both Sm2+ and Sm3+ ions. The two processes can be modeled well assuming dispersive first-order kinetics, where the rate constant of the electron transfer is given by an exponential function of the distance between the shallow electron traps and the Sm3+ centers.

Noble Metal Clusters: Applications in Energy, Environment, and Biology

“…Dual-detection strategies such as colorimetry and fl uorescence were used to quantitatively determine the presence of Human IgG using an optical immunosensor employing fl uorescent Au cluster as the signal transducing agent. [ 286 ] A schematic of the portable biosensor consisting of biomolecules immobilized on an ITO chip using poly(dopamine) fi lm is shown in Figure 14 A. A sensitivity of 5 pg mL −1 was achieved via this technique suggesting the potential of the sensor for clinical analysis.…”

Temperature and host dependence of the transition interference between f–f and f–d transitions of Sm2+ in matlockites

“…Sm 2 þ doped in inorganic crystals is interesting for investigation as these systems have many exciting properties, such as room temperature hole burning [12] or as potential pressure sensors [13]. Recent observations showed that Sm 3 þ -doped in BaFCl nanocrystals presents efficient X-ray storage properties [14][15][16]. The storage mechanism is based on the reduction of Sm 3 þ to Sm 2 þ upon exposure to ionizing radiation [15].…”

“…Recent observations showed that Sm 3 þ -doped in BaFCl nanocrystals presents efficient X-ray storage properties [14][15][16]. The storage mechanism is based on the reduction of Sm 3 þ to Sm 2 þ upon exposure to ionizing radiation [15]. Recently, photoluminescence of Sm 2 þ /Sm 3 þ doped in Sr 4 Al 14 O 25 was studied [17]; also the luminescence of Sm 2 þ was used to monitor pressure induced phase transitions in BaBr 2 [18].…”

An Insight View on Synthetic Protocol, Mechanistic and Biological Aspects of Biscoumarin Derivatives

“…It has plethora of biological activities such as anticoagulant, [12] anti-tumor, [13] vasorelaxant, [14] α-glucosidase inhibitor, [15] antibacterial, [16] anti-hepatitis C virus, [17] spasmolytic, [18] anticancer [19] and enzymatic inhibition activity. [20] Inspite of several pharmacological activities, it shows applications in the field of lasers, [21] cellular imaging, [22] optoelectronics, [23][24][25] optical whitening [26] and fluorescent markers for proteins. [27] (-)-Hydroxydecursinol, a pyranocoumarin is obtained from roots of Angelica dahurica var.…”