Surface Passivation toward Highly Stable Mn4+‐Activated Red‐Emitting Fluoride Phosphors and Enhanced Photostability for White LEDs. Issue 9 (29th March 2019)

• Record Type: Journal Article
• Authors: Zhou, Yayun; Song, Enhai; Deng, Tingting; Wang, Yuanjing; Xia, Zhiguo; Zhang, Qinyuan
• Is Part Of: Advanced materials interfaces. Volume 6:Issue 9(2019)
• Page Start: n/a
• Page End: n/a
• Publication Date: 2019-03-29
• Subjects: Mn4+‐activated phosphors -- moisture resistance -- photostability -- surface passivation -- white light‐emitting diodes; Materials science -- Periodicals; 620.11
• DOI: 10.1002/admi.201802006
• Languages: English
• ISSNs: 2196-7350

Abstract

Abstract: Mn 4+ ‐activated red‐emitting fluoride phosphors are indispensable candidates for white light emitting diodes (WLEDs) with enhanced color rendition, however, their intrinsic hydrolysis characteristics seriously restricted the durability applications. Here, a facile and general postsynthetic hydrogen peroxide (H2 O2 ) surface passivation strategy is proposed to treat the K2 XF6 :Mn 4+ (KXF, X = Ti, Si, Ge) phosphors, in which a Mn 4+ ‐rare surface protective layer appears and further covers the corresponding particles. The environment moisture can be effectively isolated by the Mn 4+ ‐rare surface passivation layer with low solubility, which will be sacrificed to protect the phosphor particles even if under extreme hydrolysis conditions. The relative external quantum efficiency of the optimized phosphors still maintains over 96% after the passivation treatment, and the relative luminous intensity still remain 97% even when soaked in water after 12 h. The correlated color temperature of high‐power WLEDs fabricated by the passivated phosphors has no remarkable change during aging process (100 days) in the high temperature (85 °C) and high humidity atmosphere (85%). It is expected that such a surface‐redox strategy can be expanded to other doped materials systems, and also opening a new perspective for the development of luminescence materials with enhanced surface stability and device duration. Abstract : This work proposes a facile H2 O2 surface passivation strategy to treat the Mn 4+ ‐activated red‐emitting fluoride phosphors, in which a Mn 4+ ‐rare surface protective layer appears. The passivation mechanism, luminescent properties, moisture resistance, and the performance of devices are been studied carefully, and such a strategy can be easily expanded to other sensitive materials for enhancing surface stability and device duration.