A novel red-emitting La2CaHfO6:Mn4+ phosphor based on double perovskite structure for pc-WLEDs lighting. Issue 23 (23rd May 2019)

• Record Type: Journal Article
• Authors: Xing, Gongcheng; Feng, Yuxin; Gao, Zhiyu; Tao, Mengxuan; Wang, Hongquan; Wei, Yi; Molokeev, Maxim S.; Li, Guogang
• Is Part Of: CrystEngComm. Volume 21:Issue 23(2019)
• Page Start: 3605
• Page End: 3612
• Publication Date: 2019-05-23
• Subjects: Crystals -- Periodicals; Crystal growth -- Periodicals; Crystallography -- Periodicals; Cristaux -- Périodiques; Cristaux -- Croissance -- Périodiques; Cristallographie -- Périodiques; 548
• DOI: 10.1039/c9ce00556k
• Languages: English
• ISSNs: 1466-8033

Abstract

Abstract : Novel narrow red-emitting double perovskite phosphor La2 CaHfO6 :Mn 4+ for pc-WLEDs lighting. Abstract : Non-rare earth doped oxides with red emission are one of the current research hotspots for achieving the warm white light range in the phosphor converted white light emitting diodes (pc-WLEDs) field. In the current work, a novel Mn 4+ -activated La2 CaHfO6 red phosphor is reported for the first time and its crystal structure is analyzed by Rietveld refinement. The photoluminescent properties of La2 CaHfO6 :Mn 4+ are investigated in detail with the help of diffuse refletance spectroscopy, photoluminescence spectroscopy, and temperature-dependent PL spectroscopy. Based on the diffuse refletance spectra, the calculated optical band gap for La2 CaHfO6 is 4.9 eV, indicating that La2 CaHfO6 could be a suitable host for activators' doping. Under 380 nm near-ultraviolet (n-UV) light excitation, the as-prepared La2 CaHfO6 :Mn 4+ displays intense red emission centered at 693 nm. Through an accurate calculation of Dq/B (2.47) and nephelauxetic effect β 1 (0.949), the origination of strong crystal field (CF) and deep-red emission is demonstrated. By combining the representative La2 CaHfO6 :0.002Mn 4+, blue BAM:Eu 2+, and green (Ba, Sr)2 SiO4 :Eu 2+ phosphors with a 380 nm UV chip to fabricate the pc-WLEDs device, a white light is obtained with low correlated color temperature (CCT = 5165 K) and high color rendering index (Ra = 87.8), demonstrating that the as-prepared La2 CaHfO6 :Mn 4+ phosphors can be used as red-emitting candidate in pc-WLEDs lighting.