Synthesis and photoluminescence of Mn4+ activated ternary-alkaline fluoride K2NaGaF6 red phosphor for warm-white LED application. Issue 79 (30th October 2017)

• Record Type: Journal Article
• Authors: Qiu, Shijie; Wei, Hengwei; Wang, Mengmeng; Zhang, Shuai; Zhou, Yang; Xu, Ling; Wang, Xiaoming; Jiao, Huan
• Is Part Of: RSC advances. Volume 7:Issue 79(2017)
• Page Start: 50396
• Page End: 50402
• Publication Date: 2017-10-30
• Subjects: Chemistry -- Periodicals; 540.5
• DOI: 10.1039/c7ra10274g
• Languages: English
• ISSNs: 2046-2069

Abstract

Abstract : A novel ternary-alkaline red emitting fluoride phosphor K2 NaGaF6 :Mn 4+ was successfully synthesized. The crystal structure, morphology, electronic band structure and luminescence properties of K2 NaGaF6 :Mn 4+ phosphors were investigated in detail. Abstract : A novel ternary-alkaline red emitting fluoride phosphor K2 NaGaF6 :Mn 4+ was successfully synthesized through co-precipitation method. The crystal structure, morphology, electronic band structure and luminescence properties of K2 NaGaF6 :Mn 4+ phosphors were investigated in details by using Rietveld refinement of X-ray diffraction data, scanning electron microscopy (SEM), density functional theory (DFT) calculation and different reaction parameters. The K2 NaGaF6 host has a cubic unit cell with the space group Fm 3̄ m and lattice parameters of a = 8.2577 (4) Å, Z = 4, V cell = 563.08 (8) Å 3 . Under blue light excitation, Mn 4+ activated K2 NaGaF6 exhibits a bright narrow-band red emission. The PL properties of the K2 NaGaF6 :Mn 4+ red phosphors were optimized with different Mn 4+ concentrations and aging times. A warm-white LED device was fabricated using a blue LED chip combined with commercial yellow YAG:Ce 3+ phosphor and synthesized K2 NaGaF6 :Mn 4+ red phosphor. The color rendering index (CRI, R a = 81.6) and corresponding color temperature (CCT = 3643 K) easily reached the commercial warm white light LED standards ( R a > 80 and CCT < 4000 K). All these results indicate that K2 NaGaF6 :Mn 4+ phosphor would be a suitable red phosphor candidate for warm-white LED applications.