Luminescence Enhancement of K 2 LiAlF 6 :Mn 4+ Phosphors by Zn 2+ -Mediated Charge Compensation for Fast-Response Backlighting Applications.

Wide-spectrum displays require narrow-band red phosphors activated by Mn, but most of them, such as KSiF:Mn, have long fluorescence decay lifetimes (>7 ms) that hinder their use in fast-response backlights. Interestingly, KLiAlF:0.05Mn has a shorter fluorescence lifetime (3.43 ms), but its disadvantage is that its luminescence intensity is relatively weak. So, in this study, the luminescence intensity of KLiAlF:0.05Mn is improved by doping with Zn. The experimental results show that enhancement of the luminous intensity is as high as 39%, the fluorescence lifetime is only increased by 13% (3.89 ms), and it is still less than 4 ms. Through experiments and differential charge density calculations, it has been revealed that the luminescence intensity improvement is due to an increased crystalline quality during the synthesis process. Specifically, the co-doping of Zn reduces the formation of impurity ions Mn and Mn and the generation of K vacancies caused by nonequivalent doping. We demonstrate the advantage of this phosphor over KSiF:Mn in terms of response speed by using a camera. It emits only weak red light after the blue chip stops working for 5 ms, indicating its potential application in next-generation fast-response displays.