Defect engineering towards anti-temperature quenching luminescence for application in light emitting diodes

Abstract

Thermal quenching (TQ) that weakens luminescent intensity is crucial for the application value of a phosphor. Here, we report a series of color-tunable phosphors Na2MgAl10O17:xEu2+ (NMA:xEu2+) from green to cyan. For optimized Eu2+ concentration of x = 0.15, its internal and external quantum efficiency can reach up to 86% and 43%, respectively. In addition, it is unexpected that NMA:0.15Eu2+ exhibits anti-temperature quenching (TQ) luminescence even up to 300 °C, which is due to the ability of the defect energy levels to counteract the usual loss of emission by TQ through EPR and TL spectral analysis. Then, a prototype w-LED lamp by using NMA:0.15Eu2+ cyan phosphor, CaAlSiN3:Eu2+ red phosphor, and 380 nm LED chip is fabricated. This work not only reports a new phosphor with high efficiency and good thermal stability of luminescence, but also brings forward a defect engineering approach for enhancing the thermal quenching resistance of a phosphor.