Structural, optical, elemental and photometric properties of Sm3+ activated Ca3Ga4O9 oxide phosphors for WLEDs

• Published in: Colloids and surfaces. A, Physicochemical and engineering aspects Physicochemical and engineering aspects, 2023-10, Vol.675, p.131973, Article 131973
• Main Authors: Govindan, V., Raja, Arumugam, Mohan Das, Gour, Dwivedi, Ranjeet, Kindrat, I., Daniel, D. Joseph
• Format: Article
• Language: English
• Subjects: Orange-Red emitter; Photometric parameters; Rare-earth ions; Sm3; XPS Analysis
• ISSN: 0927-7757; 1873-4359
• DOI: 10.1016/j.colsurfa.2023.131973

Solid-state lighting systems rely on the exceptional characteristics of phosphor-converted LEDs, including long lifetime, low energy consumption, and high brightness. This study focuses on the synthesis of Sm3+ activated Ca3Ga4O9 (CGO: Sm3+) orange-red emitting oxide phosphors using the solid-state reaction method. X-ray photoelectron spectroscopy was used to analyze the nature of bonding with the dopant ion and oxidative states of the elements in the structure. Scanning electron microscopy and energy dispersive spectroscopy revealed agglomerated particles with a flake-like structure in the Sm3+ doped sample. The optical properties of the samples were investigated using UV-Visible diffuse reflectance and photoluminescence excitation and emission analyses. The Sm3+ doped samples showed maximum excitation at 404 nm and 479 nm, with corresponding energy level transitions of 6H5/2 - 6P3/2 and 6H5/2 - 4I11/2, respectively. Emission spectra exhibited four emission maxima at 564, 601, 645, and 708 nm, representing the 4G5/2 - 6H5/2, 4G5/2-6H7/2, 4G5/2-6H9/2, and 4G5/2-6H11/2 transitions of Sm3+ ions. The Kubelka-Munk function was used to calculate the optical energy gap values. Photometric parameters, including color coordinates, correlated color temperature, and color purity, were determined. The CIE chromaticity coordinates of CGO: Sm3+ were found in the orange-red region, indicating its potential as a promising candidate for use in phosphor-converted white LEDs applications. The study concludes that Sm3+ activated CGO phosphors have great potential for use in solid-state lighting systems. [Display omitted] •Sm3+ activated gallate Ca3Ga4O9 phosphors were synthesized by solid-state reaction technique.•Environmental asymmetry around the Sm3+ ions in the structure gives electric dipole (ED) luminescence enhancement.•0.01% Sm3+ doped Ca3Ga4O9 sample shows high color purity than other doped concentrations.•The given Sm3+ doped Ca3Ga4O9 samples shows orange-red emission; which would be useful for phosphor-converted white LEDs.