Combinatorial Approach to the Development of a Single Mass YVO₄:Bi³⁺,Eu³⁺ Phosphor with Red and Green Dual Colors for High Color Rendering White Light-Emitting Diodes

Abstract

Instead of developing a novel red phosphor individually, this work proposes the production of white light by combining a near-ultraviolet/ultraviolet diode chip with blue and special yellow phosphors: the yellow phosphor includes the red and green components with high color saturation. The availability of this scheme is demonstrated by preparing a white light-emitting diode (WLED) with color rendering index (Ra) up to 90.3. The desired single-mass yellow phosphor is successfully screened out from the YVO(4):Bi(3+),Eu(3+) system by using a combinatorial chemistry approach. When the emission color and luminous efficiency are both considered, the best composition for producing white light is (Y(1-s-t)Bi(s)Eu(t))VO(4) with 0.040 < or = s < or = 0.050 and 0 < t < or = 0.015. The red component that is required for a high-Ra WLED is obtained through sensitizing luminescence of Eu(3+) by Bi(3+) in a YVO(4) host; meanwhile, both Bi(3+) and Eu(3+) emission are improved by keeping the Bi(3+) and Eu(3+) contents close to the critical concentration.

The effect of electron cloud expansion on the red luminescence of Sr4Al14O25:Mn4+ revealed by calculation of the Racah parameters

“…From what has been discussed above, we can arrive in the conclusion that the electrons in the 3d orbit of Mn 4+ have strong electrostatic repulsion when it is incorporated into the center of the AlO 6 …”

“…The white light-emitting diodes (WLEDs) show superiorities in terms of low energy consumption, high luminescence efficiency, eco-friendship without mercury pollution, long duration, unbreakable (in contrast to glass bulbs and tubes) with solid-state encapsulation, and easy transportation and installation over than traditional incandescent and fluorescent lamps, while the red phosphor is essential to obtain warm white light with high color rendering index (CRI) and low color temperature for home lighting [1][2][3][4][5][6]. The phosphor activated by Mn 4+ is a promising candidate for WLEDs application, because the narrow lines of Mn 4+ emission could enhance the luminous efficacy of radiation (LER) and the CRI given in units of lumens per watt of radiometric power (lm/ Wrad) [7].…”

“…Chen et al demonstrated a white LED device prototype with chromaticity CIE (0.3291, 0.3571), correlated color temperature 5639 K, CRI Ra 92. 6, and an efficiency 63 lm/W using the Mn 4+ activated nonstoichiometric 3SrOÁ5AL 2 O 3 and also proposed that such kind of red phosphor is suitable to package low-power WLEDs for application in special circumstances with critical requirement on color rendering, such as jewelry and cosmetic sales, due to its 1 A grade (Ra 90-100) of color rendering ability [13].…”

Structural and photoluminescence properties of red-light emitting YVO4:Eu3+ phosphor synthesized by combustion and solid-state reaction techniques: a comparative study

“…For YVO 4 number of atoms in unit cell N = 4 [40], the critical concentration of europium x c = 0.02 and volume of unit cell is 318.38 Å 3 . From the above relation, the obtained value of R c is found to be 19.66 Å , indicating that multipolar interaction is involved in concentration quenching.…”

Photoluminescence and energy transfer of YAG: Ce3+, Gd3+, Bi3+

“…Based on the survey in the literatures, Bi 3þ ion can be used as a sensitizer to improve the emission intensity of some materials. 16,17 Actually, some previous work reported about the luminescent properties that Bi 3þ ion was co-doping with other RE 3þ ion activators, and energy transfer between Bi 3þ and RE 3þ ions occurred, like 20 and CaSrS: Bi 3þ , Tm 3þ . 21 It is clear from these literatures that the Bi 3þ ion can strongly absorb excitation energy, then transfer efficiently to lower excited states of RE 3þ ions.…”