Defect and energy transfer induced abnormal thermally stable and highly efficient narrow-band green emission. (December 2022)

• Record Type: Journal Article
• Authors: Shi, Rou; Cao, Shujie; Han, Yue; Zhang, Jilin; Zhang, Xinguo; Liao, Shuzhen; Lian, Shixun
• Is Part Of: Applied materials today. Volume 29(2022)
• Publication Date: 2022-12
• Subjects: Phosphors -- Anti-thermal quenching -- Thermal stability -- Energy transfer -- LED; Materials science -- Periodicals; Materials -- Research -- Periodicals; 620.1105
• DOI: 10.1016/j.apmt.2022.101625
• Languages: English
• ISSNs: 2352-9407

Abstract

Highlights: Eu 2+, Mn 2+ -activated Na/K-β-alumina exhibits efficient narrow-band green emission. The peak and width of the green emission band are 510 and 27 nm, respectively. The introduction of Eu 2+ creates trap level and facilitates anti-thermal quenching. Internal and external QE of Na-β-alumina:0.2Eu 2+, 0.2Mn 2+ are 81.8 and 55.4%. Internal and external QE of K-β-alumina:0.2Eu 2+, 0.14Mn 2+ are 90.7 and 67.8%. Abstract: Efficient and thermally stable narrow-band green emitting phosphor is crucial for phosphor-converted light-emitting diodes (pc-LEDs), when they are used for backlighting device with wide color gamut. Herein, efficient narrow-band green-emitting Eu 2+, Mn 2+ -activated Na/K-β-alumina phosphors are obtained, which exhibit anti-thermal quenching behavior (ATQ). The internal and external quantum efficiencies of optimal phosphor Na-β-alumina:0.2Eu 2+, 0.2Mn 2+ are 81.8 and 55.4%, respectively, while those for K-β-alumina:0.2Eu 2+, 0.14Mn 2+ are 90.7 and 67.8%, respectively, which are quite higher than those for Mn 2+ singly doped one. The efficient energy transfer from Eu 2+ to Mn 2+ causes an efficient green emission with a peak at 510 nm and a FWHM value of 27 nm. Thermoluminescence indicates that the introduction of Eu 2+ creates a trap energy level, which is responsible for the dramatic change from normal thermal quenching for Mn 2+ -activated β-alumina to anti-thermal quenching for Eu 2+, Mn 2+ co-activated ones. Furthermore, the ATQ effect gradually weakens and finally becomes zero thermal quenching within 150 °C in co-doped samples by increasing the Mn 2+ content. By using the green-emitting component, the color gamut of the obtained pc-LED can reach 109% of the National Television System Council (NTSC) standard, which suggests its great application prospect for backlight. Graphical abstract: Image, graphical abstract