Synthesis, Crystal Structures, and Photoluminescence Properties of Ce³⁺-Doped Ca₂LaZr₂Ga₃O₁₂: New Garnet Green-Emitting Phosphors for White LEDs

Abstract

A new family of garnet compounds, Ca 2 LnZr 2 Ga 3 O 12 (Ln=La, Y, Lu, Gd) have been synthesized by high-temperature solid-state reaction method. The crystal structures were characterized by the X-ray diffraction (XRD) and refined by the Rietveld method. The photoluminescence properties, morphology, CIE value, quantum efficiency and thermal stability of Ca 2 LaZr 2 Ga 3 O 12 :Ce 3+ phosphors were investigated in detail to evaluate the use in w-LEDs. The photoluminescence results revealed that these phosphors have a broad excitation band in the blue region ranging from 400 nm to 470 nm and a broad green emission band centered at about 515 nm.The above results indicated that the phosphors could be effectively excited by blue light and may have potentials to be served as green-emitting phosphors for application in w-LEDs.

Thermal ionization and thermally activated crossover quenching processes for5d−4fluminescence inY3AlUeda1, Meijerink2, Dorenbos3 et al. 2017Phys. Rev. B642420View full textAdd to dashboardCite

“…However, in the 1990s, Yen et al demonstrated the existence of thermally activated ionization (thermal ionization) quenching from the Ce 3+ : 5d excited level in some compounds by photoconductivity analysis [2]. Since then both mechanisms are often discussed as being responsible for thermal quenching of luminescence in white LEDs phosphors [3][4][5][6][7]. However, the mechanism proposed is not always supported by the experimental results.…”

Luminescence properties and its red shift of blue-emitting phosphor Na3YSi3O9:Ce3+for UV LED

“…There are three mechanisms for the nonradiative energy transfer: exchange interaction, radiation reabsorption, and electric multipolar interaction. 34 Owing to the typical critical distance of the exchange interaction being about 5Å, the exchange interaction only ts the energy transfer of forbidden transitions.…”

Blue to green emission and energy transfer between Ce3+ ions in Ca15Si20O10N30

“…Firstly, with increasing the Ce 3+ content, the reabsorption begins to reduce the high-energy wing of Ce 3+ 35 emission band, which also causes the redshift of the emission band. 34 Secondly, the energy transfer between Ce 3+ ions with different coordination environments play an important role in the redshift, which will be further discussed below. The decay curves for various Ce 3+ contents at an excitation of 40 365 nm and monitored at 470 nm were measured (see Fig.…”