Novel flux-assisted synthesis for enhanced afterglow properties of (Ca,Zn)TiO3:Pr3+ phosphor

• Published in: Journal of alloys and compounds 2017-03, Vol.698, p.930-937
• Main Authors: Swati, G., Bishnoi, Swati, Singh, Paramjeet, Rajesh, B., Kumar, Gautam, Seth, Pooja, Haranath, D.
• Format: Article
• Language: English
• Subjects: Afterglow; Atoms & subatomic particles; Chemical fluxes; Chemical synthesis; Confocal imaging; Diffraction; Emission; Energy storage; Fluxes; Luminescence; Optical properties; Orthorhombic phase; Phosphors; Photoluminescence; Praseodymium; Spatial distribution; Storage systems; Thermoluminescence; Titanates; Trapping
• ISSN: 0925-8388; 1873-4669
• DOI: 10.1016/j.jallcom.2016.12.316

Selection of chemical fluxes for the phosphor synthesis is largely dependent on trial and error, so a detailed understanding of their selection is obligatory. The active role of various fluxes in influencing Pr3+ emission, afterglow, structural and morphological properties of the as-synthesized (Ca,Zn)TiO3:Pr3+ phosphor is less explored. Luminescent properties of the (Ca,Zn)TiO3:Pr3+ phosphors show a significant enhancement in Pr3+ emission with the addition of small quantities of fluxes. The persistence of the afterglow has also been increased to 15–30 min. Flux-dependent luminescent studies suggest that NH4BF4 is the best suitable flux for (Ca0.8Zn0.2)TiO3:Pr3+ phosphor among all others. X-ray diffraction studies confirm the orthorhombic phase of CaTiO3, in addition, low intensity peaks from cubic ZnTiO3 phase have also been observed. The calculated Commission Internationale de I'Eclairage (CIE) coordinates for the optimized (Ca0.8Zn0.2)TiO3:Pr3+ phosphor sample is found to be (0.66, 0.33), which is close to the ideal red coordinates with color purity of ∼96.39%. Spatial distribution of the activator ions was investigated using confocal microscopy. Thermoluminescence studies have been carried out to understand the trapping and detrapping behavior of phosphors. This multifunctional phosphor could serve fascinating applications in areas involving photon energy storage systems, strategic markings, biological staining etc. Present work focuses on the active role of various chemical fluxes in influencing Pr3+ emission, afterglow, structural and morphological properties of the as-synthesized (Ca,Zn)TiO3:Pr3+ afterglow phosphor. There is no specific rule in selecting appropriate flux for the synthesis of the phosphors hence results are important guidelines for the appropriate selection of fluxes. The mechanism involving the possible trap centers in CaZnTiO3 has also been proposed. [Display omitted] •Facile technique to produce red-emitting afterglow phosphor using different fluxes.•Active role of each flux in influencing Pr3+ emission and afterglow was studied.•Achieved efficient red PL with spectral color purity of ∼96.39%.•Achieved afterglow time variation of 15–30 min depending on flux used.