Synthesis of novel Dy³⁺ activated Ba₂CaZn₂Si₆O₁₇ phosphors for white light‐emitting diodes

Abstract

Dysprosium ion (Dy ) activated Ba CaZn Si O phosphors were synthesized using high temperature solid-state reaction method. Powder X-ray diffraction (PXRD) analysis confirmed the phase formation of the as-prepared phosphors. Scanning electron microscopy (SEM) analysis disclosed an agglomeration of particles with an irregular morphology. Under 350 nm excitation, the emission spectrum of Dy ions showed bands at 481 nm (blue), 577 nm (yellow) and 674 nm (red). The influence of the Dy concentration on its emission intensity was investigated. The optimum concentration of Dy ions in the Ba CaZn Si O :Dy phosphors were found to be x = 0.06. The critical energy transfer distance was calculated. The fluorescence lifetime was also determined for Ba CaZn Si O :0.06Dy . The Commission International deI'Eclairage (CIE) chromaticity coordinates of the phosphor were calculated to be x = 0.304, y = 0.382. The activation energy for the thermal quenching was calculated to be 0.168 eV. These results indicated that the Ba CaZn Si O :Dy phosphor might be a potential candidate for near ultraviolet (NUV)-based white light-emitting diodes.

Color-tunable luminescence, energy transfer behavior and I–V characteristics of Dy3+,Eu3+ co-doped La(PO4) phosphors for WLEDs and solar applications

“…These emission bands are ascribed to the 4 F 9/2 → 6 H 15/2 and 4 F 9/2 → 6 H 13/2 transitions of the Dy 3+ ions, respectively. 36 The literature suggests that the 4 F 9/2 → 6 H 15/2 (482 nm) is a magnetic dipole transition and the 4 F 9/2 → 6 H 13/2 (571 nm) is an electric dipole transition (hypersensitive transition) with Δ L = 2 and Δ J = 2, which is related to the host and crystal field of the host matrix. 37 It is well known that the magnetic dipole transition is more prominent than the electric dipole transition if the Dy 3+ ions are situated in high symmetry with an inversion center.…”

Luminescence and energy transfer of warm white-emitting phosphor Mg2Y2Al2Si2O12:Dy3+,Eu3+ for white LEDs

“…It can be seen that the c 2 , R p and R wp obtained by renement are all within the experimental range (c 2 < 10%, R p and R wp < 15%), proving that Dy 3+ has successfully entered the matrix and is a pure phase. In the doping process, the radius difference between doped ions and substituted ions should be within 30%, as shown in eqn (1): [29][30][31]…”

“…The cell parameters and cell volume decrease with an increase of Dy 3+ doping concentration. When Dy 3+ is used to replace Mg 2+ ions in the same lattice position, the charge is unbalanced, thus generating cation vacancies, as shown in eqn (2), and the generation of cation vacancies is helpful to the contraction of the unit cell: 29 range from 250 to 500 nm, and the maximum peak is at 367 nm, which mainly comes from the 6 H 15/2 / 6 P 5/2 transition of Dy 3+ , [31][32][33][34] and the excitation spectrum of Dy 3+ covers almost all areas from UV light to blue light. In the emission spectrum, due to the transition of 4 F 9/2 / 6 H J/2 (J ¼ 11, 13, 15) of Dy 3+ , three emission peaks at about 486, 588 and 677 nm were obtained respectively, and the two main emission peaks were located in the blue (486 nm) and yellow (588 nm) regions.…”

Structural and photoluminescence properties of Dy3+‐activated NaCaPO4 phosphor derived from solution combustion

“…Values were θ = 3 for the closest neighbour ions, θ = 6 for the electric dipole–dipole ( d–d ), θ = 8 for the electric dipole–quadrupole ( d–q ) and θ = 10 for the electric quadrupole–quadrupole ( q–q ) interactions. [ 37 ] Figure 9 shows the relationship between emission intensity ( I ) and concentration of Dy 3+ ( x ) for 325 nm, 350 nm, 365 nm, and 388 nm excitations. A graph was plotted for log( x ) vs log( I/x ) and linearly fitted.…”