Spectroscopic Evaluation of a White Light Phosphor for UV-LEDs—Ca[sub 2]NaMg[sub 2]V[sub 3]O[sub 12]:Eu[sup 3+]

Abstract

The luminescence of the vanadate garnet, Ca2NaMg2normalV3normalO12 , activated with trivalent europium is evaluated and discussed as a potential ultraviolet light-emitting diode (UV-LED) phosphor. This single phosphor is capable of converting the ultraviolet emission of a UV-LED into white light with good luminosity and color-rendering index. We have evaluated the luminescence of this material at elevated temperatures, because the junction temperatures of typical LEDs can be greater than 100°C . There is significant thermal quenching of this phosphor and emission color shift at T100°C . This is attributed to energy migration and transfer to nonradiative traps and Eu3+ within the host lattice. These implications on the use of this phosphor in UV-LED based light sources is also discussed.

The luminescence spectroscopy and thermal stability of red-emitting phosphor Ca9Eu(VO4)7

“…The junction temperature of typical LEDs can be higher than 100 8C. There are significant thermal quenching of phosphors and emission color shift at T > 100 8C [12]. However, the obvious drawback of many Eu 3+ doped vanadates is the thermal-quenching of luminescence at high temperature.…”

Synthesis and luminescent properties of nanocrystalline CaYAlO4:Sm3+ phosphors

“…Particularly, FEDs are considered as a promising display due to their thin panel, high brightness, and low power consumption. Meanwhile, near-ultraviolet phosphors-converted WLEDs have attracted great attention because of their durable energy saving, high brightness, and long lifetime in solid-state lighting devices [4,5]. To achieve high-performance devices, thus, it is necessary to develop novel phosphors with good chemical durability, high luminescence efficiency, and pure chromatic emission.…”

Vanadate Phosphors for Energy Efficient Lighting

“…However, Zhang et al [28] synthesized red emitting Sr 3 (VO 4 ) 2 :Eu 3+ nanopowders by combustion method using citric acid as a fuel, and studied the effects of temperature and amount of additive boric acid on photoluminescence properties. Conversely, it is necessary to develop phosphors to convert the NUV pump light with the range 300-400 nm into the whole visible range [29,30] and microcrystalline material which can result in high luminescent intensities. Zhu et al [31] synthesized Sr 3 (VO 4 ) 2 , Sr 2 Y 2/3-y Eu y (VO 4 ) 2 and Sr 2 Y 2/3-z Sm z (VO 4 ) 2 (z = 0, 0.1, 0.2, and 0.3) phosphors by a sol-gel method and investigated their UV excitation and emission spectra.…”

“…The high chemical and thermal property of vanadate makes its preparation diffi cult. The preparations of phosphors mainly focus on the high-temperature solid-state reactions providing agglomerated powders, which can change the structural characteristics of the powders [30,14,15,[36][37][38]. Recently, the development of new methods for the synthesis of micro or nano phosphors may increase the probability for high effective rare-earth phosphors [39][40][41][42][43][44][45][46][47][48].…”

“…The Figure 12.25 shows the emission intensity of the 3 T 2 → 1 A 1 and 3 T 1 → 1 A 1 transition of VO 4 3− group and 5 D 0 → 7 F 2 transition as a function of annealing temperature. From Figure 12.25 it is observed that almost no thermal quenching is observed at higher temperature suggesting that the migrating VO 4 3-energy is effi ciently trapped by Eu 3+ [30].…”