High brightness and vibronic luminescent behavior of YAG:Mn4+/Ca2+ red phosphor for preparing phosphor-in-glass in white LED

Abstract

Developing red-phosphors with outstanding chemical and luminescent stability is essential for fabricating phosphor-in-glass (PiG) for the next-generation solid-state lighting source because the currently commercial silica red phosphor easily suffers from corrosion by glass melt. Herein, we report the discovery of an enhanced red-emitting aluminate phosphor of Mn⁴⁺/Ca²⁺ co-doped YAG (YAGMC) using a full-solution combustion approach. This phosphor exhibits two broad excitation bands with an optimum doping level of only 0.2 at%. Under 470 nm light excitation, the emission intensity of YAGMC is greatly enhanced by 7 times compared with that of phosphor without Ca²⁺. Both Stokes and anti-Stokes bands are identified as originating from the same luminescence dynamic process. By performing a theoretical simulation, the predominant phonon in the vibronic process is determined to be 25 meV in energy. Temperature-dependent PL spectra exhibit excellent thermal stability at T < 260 K, while a serious thermal quenching phenomenon occurs at high temperatures. Finally, the YAGMC-based PiG is fabricated for constructing an LED device, and the measured results reveal a significant effect of PiG on luminous performance. From both experimental and theoretical viewpoints, our study demonstrates an efficient approach to enhancing red emission by a co-doping approach and provides a deep insight into the internal photophysical mechanism for YAGMC red phosphor.