Formation and enhancement of negative thermal quenching in emission of KGdF4:Eu3+, Yb3+@GQDs. Issue 57 (9th November 2021)

• Record Type: Journal Article
• Authors: Wu, Zhigao; Chen, Chang; Wang, Yaxiong; Luo, Chaolian; Liao, Sen; Huang, Yingheng; Ming, Junyu
• Is Part Of: RSC advances. Volume 11:Issue 57(2021)
• Page Start: 36222
• Page End: 36229
• Publication Date: 2021-11-09
• Subjects: Chemistry -- Periodicals; 540.5
• DOI: 10.1039/d1ra07413j
• Languages: English
• ISSNs: 2046-2069

Abstract

Abstract : The optimal sample exhibits a high luminescence thermal stability, due to a large negative thermal quenching. The mechanism of the negative thermal quenching is suggested as the conversion of thermal energy into light energy. Abstract : In order to obtain a red emitting phosphor with good luminescence thermal stability, a series of KGdF4 :Eu 3+, Yb 3+ @GQD (GQD: Cl-containing graphene quantum dots) red emitting phosphors have been synthesized by the co-precipitation method, and their luminescence thermal properties have also been studied in detail. It is intriguing that the negative thermal quenching (NTQ) effect is induced by the double doping of Yb 3+, and the effect is further enhanced by GQD coating. The strongest integrated PL intensities of the optimal double doped sample and the optimal GQD-coated sample are at 130 and 170 °C, in which the corresponding integrated PL intensities are presented as 117.7 and 156.5% of the initial value at 30 °C, respectively. The NTQ effect makes the optimal GQD coated sample have good luminescent thermal stability, so it can be applied for high-power WLEDs. A mechanism of energy conversion from heat to light is discussed and suggested for the effect.