Abstract
We report methodological advances that enhance the phosphorescence efficiency of a blue-emitting calcium aluminate phosphor (CaAl2O4: Eu2+, Nd3+). The investigation of long-persistence blue-emitting phosphors is highly desirable due to their promising applications, such as white LEDs; however, the development of highly efficient blue-emitting phosphors is still challenging. Here, we have quantitatively characterized the phosphorescence properties of the blue-emitting phosphor CaAl2O4:Eu2+, Nd3+ with various compositions and directly related these properties to the quality of its luminescence. We optimized the composition of the activator Eu2+ and the co-activator Nd3+, the doping conditions with alkaline earth metals, alkali metals, and Si to create crystallographic distortions and, finally, the flux conditions to find the best parameters for bright and persistent blue-emitting phosphors. Our research has identified several doping compositions with good to excellent performance, with which we have demonstrated bright and persistent phosphors with afterglow characteristics superior to those of conventional phosphors.
Highlights
Alkali metal doping significantly increases the luminescence up to 190% of the initial value, as compared to that observed for the non-doped crystal, probably due to the distorted crystal structure leading to less forbidden transitions
We have described the systematic characterization of the phosphorescence properties of CaAl2O4:Eu2+, Nd3+ synthesized with various compositions to develop bright and persistent blue-emitting phosphors
The different compositions of Eu2+ and Nd3+ in CaAl2O4:Eu2+, Nd3+ resulted in big differences in the afterglow intensity and the optimization of the activator and co-activator composition was found to be important towards a high phosphorescence intensity
Summary
Doping with Co2+ enhances the emission intensity of ZnS:Cu phosphors, the incorporation of a large amount of a dopant into the host degrades the mechanical and physical properties of the host, in the presence of moisture, which becomes chemically unstable, limiting its application [5,6,7] Another phosphor, YAG(yttrium aluminium garnet):Ce3+, is a green- or yellowemitting material; it suffers from poor color rendition and high thermal quenching[10, 11]. Development of a Blue Emitting Calcium-Aluminate Phosphor green-emitting phosphors of polycrystalline SrAl2O4 co-doped with Eu2+ and Dy3+, which resulted in improved lifetimes, intensity, and chemical stability over the previous phosphors [7]. We present in detail the phosphorescence characteristics of CaAl2O4:Eu2+, Nd3+ crystals grown with various compositions by systematic investigations on the preparation, composition, structure, and luminescence properties, aiming at improving its phosphorescence characteristics
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
