A benign approach for tailoring the photometric properties and Judd-Ofelt analysis of LaAlO_3:Sm~(3+) nanophosphors for thermal sensor and WLED applications

摘要

Sm~(3+) doped ( 1-9 mol%) Lanthanum aluminate (LaАlO_3 ) nanophosphor was prepared by solution combustion synthesis and characterized by photoluminescence (PL), powder X-ray diffraction (PXRD), UV-vis (UV-vis), scanning and transmission electron microscopy (SEM and ТЕМ). PL excitation and emission spectra, quantum efficiency, luminescence life time were studied to investigate the luminescence properties of LаАlO_3 :Sm~(3+) nanophosphor, effectively excited by near UV wavelength 406 nm.The combination of different coloured emissions in visible region presents a desired white light which leads to the WLED application. The chromaticity coordinates of the optimized concentration of Sm~(3+) was estimated to be (0.3684, 0.4066) and the corresponding correlated color temperature (ССT) was found to be ~4485 K which favors in warm white light emissive display applications. The luminescence quantum efficiency was calculated from the emission spectra using Judd-Ofelt (J-O) theory. From the analysis the estimated branching ratio (~56%) was greater than 50%, as a result the phosphor was highly suitable for display devices. The present phosphor was highly useful as thermal sensor in the temperature interval between 100 to 400 ℃ as estimated from decay time measurements.