Single Bi3+ Ultrabroadband White Luminescence in Double Perovskite via Crystal Lattice Engineering toward Light‐Emitting Diode Applications. Issue 11 (5th April 2022) - Wu, Sheng
Abstract: Single‐phase white luminescence phosphors are emerging for potential phosphor‐converted white light‐emitting diodes (pc‐WLEDs) and alternatives to trichromatic phosphor blends. In this work, Ba2 ZnWO6 :Bi 3+ phosphors are prepared by a high‐temperature solid‐state reaction method and the luminescent properties are investigated. The broadband excitation from 250 to 400 nm is perfectly matched with the emission of nearly ultraviolet (n‐UV) InGaN chip, which ultrabroadband emission band (full width at half maximum = 217 nm) can cover a wider luminescence region. Li + /Na + /K + codoping is more desirable for the ultrabroadband emission of Ba2 ZnWO6 :0.006Bi 3+ due to the charge compensation and rationally designed lattice distortion while improving the thermal stability of the phosphor. Furthermore, tunable emissions can be achieved either by changing the content of doped ions or the excitation wavelength due to the different occupation of Ba 2+ and Zn 2+ sites by Bi 3+ ions. Finally, single‐phase warm WLED (( x, y ) = (0.4170, 0.4035)) devices with a correlated color temperature of 3329 K and color rendering index of Ra = 75.3 are successfully prepared using Ba2 ZnWO6 :0.006Bi 3+, 0.03Na + phosphor, and 365 nm InGaN chips. These results indicate that Ba2 ZnWO6 :Bi 3+ has excellent potential as phosphor for n‐UV pc‐WLEDs and provides new ideas for the application of ultrabroadband emitting phosphors in WLEDs. Abstract : Developing single‐phase white emitting phosphors are meaningful but challenging in white light‐emitting diode (WLED) applications. Here, Ba2 ZnWO6 :0.006Bi 3+ phosphor is reported, where Ba 2+ /Zn 2+ sites are occupied by Bi 3+ ions via crystal lattice engineering, leading to ultrabroadband white emissions (400−800 nm) and high absorption in the nearly ultraviolet band (350−400 nm), which in total presents great potential for applications in single‐phase warm WLEDs.