Liangjun Zhou,Wenxi Wang,Dekang Xu,Zhenyu Wang,Zhibin Yi,Min Wang,Zhouguang Lu
Thermal quenching of luminescence is the most critical problem for rare earth doped phosphors used in light-emitting diodes (LEDs). Herein, we demonstrate that thermal quenching can be considerably suppressed via the negative thermal expansion effect in Zr(WO 4 ) 2 that serves as host for Eu 3+ red emission. The photoluminescence (PL) intensity is surprisingly enhanced by 130% when the temperature is raised from room temperature to 100 °C. As temperature further increases to 160 °C, the PL intensity turns to reduce, which is still 1.4 times of that at room-temperature. Moreover, Zr(WO 4 ) 2 :15%Eu phosphor has good durability, which still exhibits strong red luminescence (only 13% loss) after being kept in 85 °C/85% relative humidity chamber for 240 h. The anti-thermal quenching of Eu 3+ luminescence can be ascribed mainly to the following two factors: first one is the thermal-enhanced energy transfer between Eu 3+ ions induced by the contraction of Zr(WO 4 ) 2 unit-cell volume that leads to the strong structural rigidity of host lattice; second one would be electron traps in the host that favors the increase of electrons on the excited energy levels. This important anti-thermal quenching effect induced from the negative thermal expansion of the host matrix may stimulates a novel and efficient approach to design highly thermal stable phosphors for next-generation LEDs.
Jiaying Yang,Yiman Qian,Jingqi Yan,Jiayin Li,Pengfei Liu
Advanced oxidation processes (AOPs) surpass photocatalytic methods in energy efficiency, enabling organic dye degradation under mild conditions without light activation. In this study, we crafted a highly effective Zr(WO 4 ) 2 catalyst for AOPs, rigorously characterized through SEM, TEM, TG-DTA, N 2 -sorption, XRD, and XPS analyses. The system demonstrated exceptional catalytic performance, achieving 95.62 % phenol removal (2 mg/L) within 60 min using only 0.1 g/L Zr(WO 4 ) 2 and 1 mM PMS, with singlet oxygen ( 1 O 2 ) identified as the dominant reactive species. Crucially, the synergistic redox interplay between Zr 4+ and WO 4 2− surface species emerged as the critical driver for efficient PMS activation. Beyond its catalytic prowess, the Zr(WO 4 ) 2 system exhibited remarkable reusability and versatility across multiple applications, while generating treated water with minimal toxicity, positioning it as an environmentally promising solution.
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