A novel pale‐yellow Ba₂ZnGe₂O₇:Bi³⁺ phosphor with site‐selected excitation and small thermal quenching

Abstract

A novel pale‐yellow Ba2ZnGe2O7:Bi3+ phosphor with site‐selected excitation and small thermal quenching was synthesized by conventional solid‐state sintering. The crystal structure and luminescence properties have been investigated in detail for the first time using XRD patterns, photoluminescence spectra, diffuse reflection spectra, decay curves, and temperature‐dependent emission spectra. The results reveal that the excitation spectrum of Ba2ZnGe2O7:Bi3+ phosphor locates in the near‐ultraviolet region of 300‐400 nm, and its emission shows an obvious site‐selective excitation phenomenon since Bi3+ ions occupy two different crystallographic sites in the Ba2ZnGe2O7 host. When excited under 360 nm, the phosphors show a pale‐yellow emission in the range of 400‐700 nm with the maximum peaking at 520 nm, while when excited under 316 nm, the phosphors show a blue emission in the range of 400‐700 nm with the maximum peaking at 480 nm. In addition, the emission of Ba2ZnGe2O7:Bi3+ can also be easily controlled by changing the Bi3+ concentration. The Ba2ZnGe2O7:Bi3+ phosphor has small thermal quenching, and its emission intensity only decreases by 2% at 200°C. The results indicate that this novel pale‐yellow Ba2ZnGe2O7:Bi3+ phosphor could be conducive to the development of white light‐emitting diodes.

Luminescence and temperature‐sensing properties of Y4GeO8:Bi3+,Eu3+ phosphor

“…By monitoring the emission at 517 nm, two broad excitation bands centered at 290 and 347 nm are detected in the excitation spectra. The former originates from 1 S 0 → 1 P 1 absorption of Bi 3+ ions, and the later comes from 1 S 0 → 3 P 1 absorption of Bi 3+ ions 33,34 . The small sharp peak at 420 nm in excitation spectra is derived from the signal peak of the spectrometer and does not affect the measurement results.…”

“…The former originates from 1 S 0 → 1 P 1 absorption of Bi 3+ ions, and the later comes from 1 S 0 → 3 P 1 absorption of Bi 3+ ions. 33,34 The small sharp peak at 420 nm in excitation spectra is derived from the signal peak of the spectrometer and does not affect the measurement results. Under the excitation of 290 and 347 nm, Y 4 GeO 8 :0.2Bi 3+ displays a cyan broad band centered on 517 nm in both cases, which is corresponded to the emission of Bi 3+ ions from 3 P 1 → 1 S 0 transition.…”

Strong f–f excitation in hafnium germanate: Near‐UV LED and cathode beam–pumped red phosphor with thermal robustness

“…Germanate, a suitable doping host, has attracted considerable attention due to its rigid framework structure, stable physicochemical properties, diverse cationic sites, and easy synthesis, as exhibited in Ba 2 ZnGe 2 O 7 :Bi 3+ , 25 Sr 2 MgGe 2 O 7 :Mn 4+ , 26 Sr 2 ZnGe 2 O 7 :Eu 3+ , 27 Mg 14 Ge 5 O 24 :Mn 4+ , 28 NaYGeO 4 :Eu 3+ , 29 and La 3 Ga 5 GeO 14 :Cr 3+ 30 . BaHfGe 3 O 9 is a kind of germanate with a hexagonal benitoite structure reported by Choisnet in 1975 31 .…”

Enhanced luminescence properties of Ca1+xSr2−xAl2O6:Eu3+ (0 ≤ x ≤ 1) red phosphors based on composition modulation

“…[1][2][3][4][5][6][7] Currently, the most common way to fabricate commercial WLEDs is by combining a blue InGaN LED chip with a YAG:Ce 3+ (Y 3 Al 5 O 12 :Ce 3+ ) yellow-emitting phosphor. [8][9][10][11] Nonetheless, owing to the deciency of the red-emitting component, the devices have some disadvantages, such as a high correlated color temperature (CCT) and a poor color rendering index (CRI). [12][13][14] Consequently, these WLEDs do not meet the requirements for indoor illuminations, which limit their further development as light sources in this eld.…”