Role of rhodamine-B dye encapsulated mesoporous SiO₂ in color tuning of SrAl₂O₄:Eu²⁺,Dy³⁺ composite long lasting phosphor

A novel color tunable dye encapsulated mesoporous SiO₂/SrAl₂O₄:Eu²⁺,Dy³⁺ composite long lasting phosphor (LLP) is developed. The color tuning was obtained by mixing the SrAl₂O₄:Eu²⁺,Dy³⁺ (SAO) phosphor with rhodamine-B encapsulated mesoporous silica nanoparticles (MSNp-RhB) with an appropriate ratio. The photoluminescence emission spectra, phosphorescence spectra, photometric and phosphorescence decay measurement were utilized to characterize the composite phosphor. The composite LLP can be excited by UV lamp and also visible light due to broad excitation spectrum of SAO. A near white light emission was achieved with color co-ordinates (0.34, 0.39) and color temperature 5267 K. The detailed process is described here. The nature of phosphorescence decay of the composite LLP did not change with time which ensures constant and steady color during the decay process. The results indicate that the composite LLP can be potentially applicable as a new long lasting phosphor used in the field of emergency light, display, luminous paint and light emitting diode applications.