Synthesis, characterization, photoluminescence and thermally stimulated luminescence investigations of orange red-emitting Sm3+-doped ZnAl2O4 phosphor

Abstract

Sm 3+-doped ZnAl 2 O 4 phosphor was synthesized by citrate sol-gel method and characterized using X-ray diffraction and scanning electron microscopy to identify the crystalline phase and determine the particle size. Photoluminescence (PL) studies on the sample showed emission peaks at 563, 601, 646 and 707 nm with λ ex = 230 nm corresponding to the 4 G 5/2 → 6 H 5/2 , 4 G 5/2 → 6 H 7/2 , 4 G 5/2 → 6 H 9/2 and 4 G 5/2 → 6 H 11/2 transitions, respectively, due to Sm 3+ ions. PL lifetime decay studies confirmed that Sm 3+ ions partly entered into the lattice by replacing Al 3+ ions and remaining located at the surface of ZnAl 2 O 4 host matrix. Thermally stimulated luminescence (TSL) studies of γ-irradiated Sm 3+-doped ZnAl 2 O 4 sample showed two glow peaks at 440 and 495 K, the former being most intense than the latter. The trap parameters were determined using different heating rate methods. Spectral characteristics of the TSL glow showed emission around 565, 599 and 641 nm, indicating the role of Sm 3+ ion as the luminescent centre. A probable mechanism for the prominent TSL glow peak, observed at 440 K, was proposed. CIE chromaticity coordinates for the system was evaluated, which suggested that Sm 3+-doped ZnAl 2 O 4 could be employed as a potential orange red-emitting phosphor.

Improvement of the optical and photocatalytic properties of ZnAl2O4: 1% La3+, x% Pb2+ nanoparticles synthesized by citrate sol-gel route

“…Because, the ionic radius of La 3+ (1.04 Å) [27] is greater than those of the tetrahedral (Zn 2+ (0.60 Ǻ), Al 3+ (0.39 Ǻ)) and octahedral (Zn 2+ (0.74 Ǻ, Al 3+ (0.54 Ǻ)) sites of ZnAl2O4 system [19]. Similar results have been previous observed in the ZnAl2O4 doped by Lanthanides elements [11,14,18].The most intense (220) and (311) diffraction peaks for all samples are illustrated in figure 1.b. We observe also that when Pb 2+ is added up to 1.5 % mol to the S0 sample, the shift of the most intense peaks is towards the large angles, then beyond this percentage of Pb 2+ , the shift changes by meaning.…”

“…disordered) cation distribution [17]. Many synthesis methods preparation of ZnAl2O4 have been reported, such as: hydrothermal [10,18]; citrate [1,19,20], sol-gel [21][22], combustion [13,[23][24][25], pyrolysis [14,26], co-precipitation [15,[27][28][29] and solvothermal [30][31]. While doping ZnAl2O4 was carried out with transition metals or rare earths depending on the intended application [6-7, 14, 32].…”

Effect of annealing on luminescence of Eu3+- and Sm3+-doped Mg2TiO4 nanoparticles

“…However, the intensification of emission with the increase of annealing temperature is smaller than in Eu 3 þ -doped magnesium titanate. Kumar et al [37] noticed a similar trend in Sm 3 þ -doped ZnAl 2 O 4 spinel structure where the calcination temperature is directly proportional to the emission intensity.…”

Microwave-Assisted Hydrothermal Synthesis of Zinc-Aluminum Spinel ZnAl2O4

“…Zinc-aluminum spinel doped with ions of various chemical elements, such as Co 3+ , Er 3+ , Eu 3+ , Yb 3+ , Tb 3+ and Mn 3+ , also has interesting properties. Spinel doped with these elements exhibits excellent luminescent properties [ 56 , 57 , 58 , 59 , 60 , 61 , 62 , 63 , 64 , 65 ].…”