Synthesis and Photoluminescence of a New Chlorogermanate Phosphor Ca₈Mg(GeO₄)₄Cl₂:Eu²⁺

Abstract

A new chlorogermanate compound Ca8Mg(GeO4)4Cl2 (CMGC) was synthesized via high‐temperature solid‐state reaction for the first time. The crystal structure of CMGC had been refined and determined from the XRD profiles by Rietveld refinement method, which belong to space group Fd‐3m with the lattice constants a = b = c = 15.1760(25) Å. Photoluminescence properties of CMGC:Eu2+ phosphors were investigated by absorption spectra, excitation, and emission spectra. The occupy situation and energy transfer were investigated by decay lifetimes and emission spectra under different excitation wavelengths. Thermal stability was also measured. The results show that the absorption spectra of CMGC:Eu2+ phosphors cover from 250 to 500 nm. Under 365 and 435 nm excitation, the emission spectra of CMGC:Eu2+ phosphors show blue‐green (centered at 425 and 510 nm) and green (centered at 510 nm) emission, respectively, which attributed to Eu2+ ions occupying different crystal sites. Our results indicated that CMGC:Eu2+ phosphors had a potential application use for white light‐emitting diodes.

A Single‐Phase Phosphor NaLa9 (GeO4)6O2: Tm3+, Dy3+ for Near Ultraviolet‐White LED and Field‐Emission Display

“…Since Ge is in the same main group as Si in the periodic table of the elements and with the similar chemical properties to Si, germanate has also been of interest recently. Studies have been reported on Ca 8 Mg(GeO 4 ) 4 Cl 2 :Eu 2+ , Ln 2 Ca(GeO 3 ) 4 (Ln = Gd, Ho, Er, Yb, Y), etc. In our previous work, a red‐emitting phosphor NaLa 9 (GeO 4 ) 6 O 2 : Eu 3+ has been investigated and in this study, a single‐phase white‐light‐emitting phosphor NaLa 9 (GeO 4 ) 6 O 2 : Dy 3+ , Tm 3+ has been designed for its better luminescent properties compared with NaLa 9 (GeO 4 ) 6 O 2 : Eu 3+ mainly in PL and CL which make it a potential candidate for NUV‐WLEDs and FEDs.…”

Eu2+‐Doped Yellow‐Emitting CsBaB3O6 Glass‐Ceramic Prepared by Melt Quenching and Re‐Crystallization Method

“…A BSORPTION and emission spectra of Eu 2+ ions usually comprise a broad band due to transitions between the 4f 7 ground state and the crystal-field components of the 4f 6 5d 1 excited state configuration. 1,2 Luminescence transitions of 4f 6 5d 1 ?4f 7 in Eu 2+ -doped in inorganic materials are parity allowed, so its cross section is large. The luminescent properties of Eu 2+ -activated solids have been intensively investigated during the past decades because of the significant applications in luminescence performance and displays such as plasma display devices, field emission displays, cathode ray tubes, electroluminescent displays, laser generation, and white light-emitting diodes (W-LEDs) fabricated with near-UV chips, long-lasting fluorescence, X-ray screen, and medical devices, etc.…”

“…The luminescent properties of Eu 2+ -activated solids have been intensively investigated during the past decades because of the significant applications in luminescence performance and displays such as plasma display devices, field emission displays, cathode ray tubes, electroluminescent displays, laser generation, and white light-emitting diodes (W-LEDs) fabricated with near-UV chips, long-lasting fluorescence, X-ray screen, and medical devices, etc. [3][4][5][6][7][8][9][10] The luminescence wavelength of Eu 2+ ions strongly depends on the host, which varies from ultraviolet to red wavelength region. Therefore, the choice of hosts considerably affects the optical properties of Eu 2+ ions.…”

Synthesis, structure and luminescence characteristics of a novel red phosphor NaLa9(GeO4)6O2:Eu3+for light emitting diodes and field emission displays

“…24 Among numerous of rare earth ions, Eu 3+ was usually chosen as a typical and efficient activator for red emitting phosphor and its photoluminescence emission strongly depends on the symmetry of the crystal structure of the Eu 3+ -occupied site in the host. Meanwhile, the difference of the electronegativities of Ge and O (∆X = 1.43) is close to that of Si and O (∆X = 1.54), so rare earth doped germanates could also have excellent optical properties.…”