Zhou JWang YChen YZhou YMilićević BZhou LYan JShi JRU-SHI LIUWu M.2021-08-032021-08-03202114337851https://www.scopus.com/inward/record.uri?eid=2-s2.0-85098105057&doi=10.1002%2fanie.202011022&partnerID=40&md5=765bffdee6d050fb336ef76ce8e695a9https://scholars.lib.ntu.edu.tw/handle/123456789/575826A solvent-vapor transport route produces centimeter-sized single-crystal red phosphors. The epitaxial growth route to yield its core–shell structure at ambient temperature was adopted. These red phosphors could be applied in all-inorganic WLED devices. Cs2TiF6:Mn4+ (CTFM) single crystal provides enhancement of quantum efficiency, moisture resistance, and thermal stability compared to polycrystalline powders. The internal quantum efficiency can reach as high as 98.7 %. To further improve waterproof stability, the Cs2TiF6 (CTF) shell with tunable thickness has been epitaxially grown on the CTFM single crystal surface and a unique three-step photoluminescence intensity evolution mechanism has been proposed. By combining as-prepared CTFM@CTF core–shell structured single crystal, YAG:Ce single crystal and blue-chip, warm WLEDs with excellent color rendition (Ra=90, R9=94), low correlated color temperature (CCT=3155 K), and high luminous efficacy were fabricated without any organic resins.Efficiency; Light emission; Phosphors; Quantum efficiency; Shells (structures); Titanium compounds; Yttrium aluminum garnet; Correlated color temperature; Evolution mechanism; High luminous efficacy; Internal quantum efficiency; Moisture resistance; Photoluminescence intensities; Polycrystalline powders; Water-resistances; Crystal structurejournal article10.1002/anie.202011022332004992-s2.0-85098105057