Improvement in luminescent properties and thermo-optical conversion mechanism of Na2SiF6:Mn4+, K+@GQDs. Issue 37 (29th June 2021)

• Record Type: Journal Article
• Authors: Zhong, Xue; Wang, Tianman; Li, Yuelan; Yu, Yan; Chen, Long; Liao, Sen; Huang, Yingheng; Long, Jinqiao
• Is Part Of: RSC advances. Volume 11:Issue 37(2021)
• Page Start: 23023
• Page End: 23035
• Publication Date: 2021-06-29
• Subjects: Chemistry -- Periodicals; 540.5
• DOI: 10.1039/d1ra02449c
• Languages: English
• ISSNs: 2046-2069

Abstract

Abstract : The optimal sample exhibits high stability due to large negative thermal quenching. The mechanism of negative thermal quenching is suggested to be the conversion of thermal energy into light energy. Abstract : Herein, a series of NSF:0.05Mn 4+, 0.04K + @GQD (NSF: Na2 SiF6, GQDs: Cl-containing graphene quantum dot) phosphors was prepared. Double enhancement effects on the luminescent intensity and thermal stability triggered by the GQD coating were observed for the optimal sample as follows: (a) its PL intensity was 1.72 times that of the uncoated control sample and (b) its luminescent thermal stability was greatly enhanced, with integrated PL intensities of 120, 150 and 180 °C to 179.7%, 175.8%, and 119.3% of the initial value at 25 °C, respectively. It is proposed that the above-mentioned behaviors involve a change in some of the thermal energy into light energy via a phonon-induced mechanism. The thermal stability analysis results showed that the optimal sample is suitable for application in high-power WLEDs. Specifically, warm white light with a low correlated color temperature, high luminescent efficiency and high color rendering index was obtained from the prototype WLEDs using the optimal sample as a red-emitting component.