Synthesis and Characterization of europium doped barium magnesium aluminate (BaMgAl 10 O 17 :Eu 2+ ) and lanthanum yttrium phosphate (LaYPO 4 :Eu 2+ ) nanophosphors

Abstract

Over a decade after adapting the definition and long-term vision for nanotechnology, the programs around the world have achieved remarkable results regarding scientific discoveries that span better understanding of the smallest living structures and functions of matter at the nanoscale. The current scenario of emerging field of luminescent material (phosphor) has a great interest in optoelectronics and solid-state lighting applications for industrial purpose. In the present work, we have reported, aluminate and phosphate based nanophosphors particularly for major applications such as fluorescent lamp and solid-state lighting. These two nanophosphors represent blue and red color emission under the ultraviolet (UV) light excitation source. The synthesis and characterization of europium doped barium magnesium aluminate (BaMgAl₁₀O₁₇:Eu²⁺) and lanthanum yttrium phosphate (LaYPO₄:Eu²⁺) nanophosphors have been discussed in detail. For the synthesis of BaMgAl₁₀O₁₇:Eu²⁺ and LaYPO₄:Eu²⁺, we have used auto-combustion and sol-gel techniques respectively, and all the precursor salts have been taken in stoichiometric proportions. The structural, morphological and optical properties of the synthesized nanophosphors have been characterized using X-ray diffraction pattern, scanning electron microscopy (SEM) and photoluminescence measurements, respectively. It has been observed that the auto-combustion and sol-gel processes result nanoparticles with average size ~55 and 22 nm, respectively. SEM observations showed truncated fractal-like morphology of the particles. The photoluminescence studies of BaMgAl₁₀O₁₇:Eu²⁺ and LaYPO₄:Eu²⁺ nanophosphor under ~300 and 250 nm excitation exhibit dominant emission peaks at 465 and 620 nm respectively. The corresponding energy transition in BaMgAl₁₀O₁₇:Eu²⁺ at 465 emission peak attributed to 4f⁶5d¹→4f⁷ transition of the europium ion. The energy transition of trapped electrons hasbeen proved by time-resolved photoluminescence spectra which recorded at four milliseconds for both BaMgAl₁₀O₁₇:Eu²⁺ and LaYPO₄:Eu²⁺ nanophosphors. These results perfectly established the suitability of these nanophosphors in improving the efficiency of fluorescent lamp and nanoelectronics devices.