Synthesis and characterization of highly Eu3+-doped CaY2Sb2(ZnO4)3 red phosphors with abnormal thermal quenching performance for w-LEDs application

In the present work, a series of zincate CaY 2 Sb 2 (ZnO 4 ) 3 :Eu 3+ phosphors were successfully obtained via the conventional solid-state method at high temperature. The phase purity, morphology, element mapping, photoluminescence excitation/emission (PLE/PL), and decay time of the obtained phosphors were investigated systematically. Results show that the synthesized samples demonstrate the strongest red-emitting peak at 610 nm under the n-ultraviolet (n-UV) 395 nm excitation. The Judd-Ofelt parameters (Ω 2 , Ω 4 ), radiative transition rates, and branching ratios ( β 0 J, J  = 2, 4) of CaY 2 Sb 2 (ZnO 4 ) 3 :Eu 3+ to explore the Eu 3+ -coordinated environment in the host matrix. The concentration quenching of CaY 2 Sb 2 (ZnO 4 ) 3 :2 x Eu 3+ phosphors happened until at high doping concentration of x  = 50 mol%. CaY 2 Sb 2 (ZnO 4 ) 3 :100 mol%Eu 3+ sample presented the excellent thermal stability with abnormal thermal quenching behavior. Compared with the commercial Y 2 O 3 :Eu 3+ red phosphor , the luminescent intensity of the prepared phosphor is 1.14 times stronger. The high internal quantum efficiency (IQE) of CaY 2 Sb 2 (ZnO 4 ) 3 :100 mol%Eu 3+ phosphor is 79.20%. In addition, the fabricated red and white light-emitting diodes (w-LEDs) both emit bright light. The w-LED demonstrates a high color rendering index ( R a  = 96) and a low correlated color temperature (CCT = 5249 K). Therefore, the prepared red-emitting phosphor has a promising application in w-LEDs.