A novel Mn4+-activated fluoride red phosphor Cs30(Nb2O2F9)9(OH)3·H2O:Mn4+ with good waterproof stability for WLEDs

Due to the presence of Nb 5+ , a Mn 4+ -doped compound (denoted as CNOFM) shows very good waterproof stability, even without any surface modification. Warm WLEDs with a high color rendering index have been fabricated using the CNOFM red phosphor.