Highly Efficient Green‐to‐Yellowish‐Orange Emitting Eu2+‐Doped Pyrophosphate Phosphors with Superior Thermal Quenching Resistance for w‐LEDs. Issue 6 (10th January 2020)

• Record Type: Journal Article
• Authors: Wei, Yi; Gao, Zhiyu; Liu, Siwei; Chen, Shuoting; Xing, Gongcheng; Wang, Wei; Dang, Peipei; Al Kheraif, Abdulaziz A.; Li, Guogang; Lin, Jun
• Is Part Of: Advanced optical materials. Volume 8:Issue 6(2020)
• Page Start: n/a
• Page End: n/a
• Publication Date: 2020-01-10
• Subjects: green to yellowish‐orange emission -- high luminescence efficiency -- pyrophosphates -- thermal quenching resistance; Optical materials -- Periodicals; Photonics -- Periodicals; 620.11295
• DOI: 10.1002/adom.201901859
• Languages: English
• ISSNs: 2195-1071

Abstract

Abstract: Highly efficient green/yellowish‐orange phosphors with low thermal quenching behavior are urgently required to improve the luminescence efficiency, color stability, and color rendering of phosphor‐converted white light emitting diodes (w‐LEDs). Herein, a novel green Cs2 BaP2 O7 :0.01Eu 2+ phosphor with high luminescence efficiency (82.7%) and thermal quenching behavior (92.5% at 423 K) is reported. Besides, a further luminescence improvement in the quantum yield (98.9%) and thermal quenching resistance (120% at 448 K) is successfully achieved in green/yellowish‐orange color‐tunable Cs2 MP2 O7 :0.01Eu 2+ (M = Ba, Sr, and Ca) phosphors. Surprisingly, these green/yellowish‐orange Cs2 MP2 O7 :0.01Eu 2+ (M = Ba, Sr, and Ca) phosphors even have a prior advantage over the commercial green β‐SiAlON:Eu 2+ and yellow YAG:Ce 3+ phosphors. The corresponding spectral adjustment and thermal stability mechanisms are revealed, related to the optimization of local lattice symmetry. The prototype w‐LEDs exhibit warm white light with CIE color coordinate at (0.337, 0.322). The color rendering index, corrected color temperature, and luminescence efficiency can reach 92.6, 4044 K, and 152.56 lm W −1, respectively. In general, the as‐reported green/yellowish‐orange Eu 2+ ‐doped pyrophosphate phosphors are promising candidates in the future high‐quality w‐LEDs applications. The proposal of local lattice symmetry modulation can provide a new approach to exploit novel phosphors with excellent thermal quenching resistance. Abstract : High luminescence efficiency (internal quantum yield exceeding 98.9%) and excellent thermal quenching resistance (photoluminescence integrated intensity and peak intensity at 448 K enhanced to 120% and 110%, respectively, of the original intensity at room temperature) are successfully achieved in novel Eu 2+ ‐doped green‐to‐yellowish‐orange pyrophosphate Cs2 MP2 O7 (M = Ca, Sr, and Ba) phosphors for high‐performance white light emitting diodes.