Photoluminescence characterization and heat treatment effect on luminescence behavior of BaTa₂O₆:Dy³⁺ phosphor

Abstract

Undoped and Dy3+‐doped barium tantalate phosphors were synthesized by the solid‐state reaction method at 1425°C. Also, 10 mol% Dy3+‐doped BaTa2O6 was sintered between 1150 and 1425°C in order to determine temperature effect on structural and luminescence properties. Afterwards, they were characterized by XRD, SEM‐EDS and photoluminescence (PL) analyses. PL spectra exhibited the excitation peaks between 300 and 440 nm. Two typical emissions were observed at 486.2 nm (blue) and 577.7 nm (yellow) due to the 4F9/2→6H15/2 and 4F9/2→6H13/2 transitions, respectively. Emission intensities increased with increasing doping concentration of Dy3+ up to 10 mol% and then decreased due to the concentration quenching effect. Moreover, depending on the increase in heat treatment temperature, the intensity of emission reached maximum at 1425°C. The calculated CIE chromaticity coordinates of phosphors located in the white light region.

Judd–Ofelt parameters and X-ray irradiation results of MNb2O6:Eu3+ (M = Sr, Cd, Ni) phosphors synthesized via a molten salt method

“…The R-value or ( 5 D 0 / 7 F 2 )/ ( 5 D 0 / 7 F 1 ) ratio can be used as an indicator to predict the symmetry of the local environment of Eu 3+ ion; whereby a high R-value indicates an increase in Eu 3+ -O 2À covalency and a low symmetry/more distorted environment. 5 As seen in Fig. 8, the Rvalues of the PL-RL mechanism for CdNb 2 O 6 :Eu 3+ and NiNb 2 -O 6 :Eu 3+ were close to each other.…”

“…The PL emissions of the CdNb 2 O 6 :Eu 3+ and NiNb 2 O 6 :Eu 3+ increased up to 6 mol%, while the SrNb 2 O 6 :Eu 3+ emission decreased aer 3 mol% due to the concentration quenching or nonradiative energy transfer, which originated from the host defects and the distance RE 3+ -RE 3+ . 5,6 In all the examples, the emission intensities of the 5 D 0 / 7 F 2 (electric dipole) transition were higher than the 5 D 0 / 7 F 1 (magnetic dipole) transition. This indicates that the Eu 3+ ions occupied crystallographic sites without an inversion center.…”

“…The broad CT bands with peak centers at 277.4 nm (SrNb 2 O 6 :Eu 3+ ), 276.6 nm (CdNb 2 O 6 :Eu 3+ ), and 277.7 nm (NiNb 2 O 6 :Eu 3+ ) could be attributed to the Eu 3+ -O 2À charge transfer, which results from the transition of 2p electrons of O 2À to the empty 4f orbitals of Eu 3+ ion. 5,6…”

“…The observed lifetimes (s) of the MNb 2 O 6 :Eu 3+ (M ¼ Sr, Cd, Ni) phosphors for the 5 Table 2). The observed lifetime (s) represents the sum of nonradiative (s nr ) and the radiative (s r ) lifetimes, which are expressed by eqn (10).…”

“…Today, trivalent RE ions have a wide range of applications, such as high-performance luminescent devices, magnets, catalysts, and other functional materials. [1][2][3][4][5][6][7] When the host lattice is activated by RE 3+ ions, besides PL, they can cause changes in RL features. In the radioluminescence mechanism, high-energy ionizing radiation (X-rays, alpha particles, and electrons) instantly transforms into thousands of low-energy photons (1-6 eV).…”