Tunable dual‐mode emission with excellent thermal stability in Ca₄ZrGe₃O₁₂:Eu phosphors prepared in air for NUV‐LEDs

Abstract

Novel dual valence Eu‐doped Ca4ZrGe3O12 (CZGO) phosphors were successfully fabricated in air atmosphere through a solid‐state route. Their crystal structure, photoluminescence properties as well as thermal quenching performance were investigated systematically. The spectra show that part of Eu3+ were reduced to Eu2+ and the mechanism is interpreted by the charge compensation. By altering Eu concentration, multi‐color luminescence covering from blue to red is realized when irradiated by 370 nm light, which perfectly matches with the near ultraviolet (NUV) light‐emitting diode (LED) chips. More importantly, under NUV excitation, luminescent intensities are almost unchanged even up to 423 K. And chromaticity exhibits only a tiny shift with growing temperature. Such suitable luminescent spectra and superior thermal stability indicate that CZGO:Eu phosphors are promising candidates for blue‐red components in NUV pumped W‐LEDs. Finally, the fabricated W‐LED based on the combination of CZGO:Eu phosphors, Ba2SiO4:Eu2+ and a 365 nm NUV‐LED chip gives a high color rendering index, a low correlated color temperature and suitable CIE chromaticity coordinates.

Highly efficient yellow‐orange emission and superior thermal stability of Ba2YAl3Si2O12:Ce3+ for high‐power solid lighting

“…[5][6][7] Although co-doping rare earth ions (Pr 3+ , Eu 3+ , Sm 3+ , etc) or transition metal ions (Mn 2+ ) could inject more red component, the augment is quite limited and the thermal stability is significantly decreased. [8][9][10][11][12] Thus, another nascent technology takes a different approach. The peculiar garnet structure is found to offer a remarkable flexibility in accommodating various cations to change the crystal filed strength and the covalency of Ce 3+ -O 2− , which could bring various emission spectra covering green to orange region.…”

“…However, the poor color rendering resulted from the deficiency of the red component has already restricted and hindered its further application in some certain fields 5‐7 . Although co‐doping rare earth ions (Pr 3+ , Eu 3+ , Sm 3+ , etc) or transition metal ions (Mn 2+ ) could inject more red component, the augment is quite limited and the thermal stability is significantly decreased 8‐12 . Thus, another nascent technology takes a different approach.…”

Valence regulation in europium-doped fluoride phosphor for high-resolution X-ray time-lapse imaging

“…Besides, the XPS of Eu in the original phosphor indicates the self-reduction of Eu 2+ during the high-temperature solid-state reaction. The process is as follows [32][33][34] (Fig. S5, ESI †).…”

(3+1)-Dimensional Modulated Structure and Tb3+-Doped Luminescence for Vanadate Na3La(VO4)2

“…As a typical luminescent material, it is made up of a host lattice and an activation ion, which may be usually a transition or rare-earth ion. Undoubtedly, inorganic oxysalts are good choice for the host lattice and, in recent years, the studies exploring new efficient phosphors for lighting and back-light displays in such a system are always a hot topic, including Mg 2 TiO 4 :Mn 4+ , Gd 2 ZnTiO 6 :Bi 3+ , Na 2 GdPO 4 F 2 :RE (RE = Sm 3+ , Ce 3+ , and Tb 3+ ), (Sr,Ba) 2 LaGaO 5 :Bi 3+ ,Eu 3+ , Ca 4 ZrGe 3 O 12 :Eu, and so on.…”