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The addition of a red-emitting phosphor to YAG:Ce3+-based white light-emitting diodes (WLEDs) greatly facilitates their applications in the field of high-color-rendering-index warm solid-state lighting. It is highly desirable to develop a red phosphor with satisfactory spectral features and low synthesis cost. In this study, a novel non-rare-earth and nonequivalent doping type of Cs2NbOF5:Mn4+ oxyfluoride red-emitting phosphor with high luminous efficiency was obtained via a facile room-temperature co-precipitation method, and its morphology and luminescent properties were investigated in detail. The Cs2NbOF5:Mn4+ phosphor with micro-rod-like morphology exhibited broad band absorption at blue light region (∼474 nm) and narrow bandwidth emissions at red region (∼633 nm). The color purity of the Cs2NbOF5:Mn4+ phosphor was calculated to be about 99%, and the internal quantum yield (QY) under 474 nm excitation was 63.4%. The concentration quenching of Mn4+ in Cs2NbOF5 matrix was mainly due to dipole-dipole interactions, and the activation energy of temperature quenching was calculated to be ∼0.2610 eV. The demonstration of a blue InGaN LED chip in combination with a blend of newly developed Cs2NbOF5:Mn4+ red phosphor and YAG:Ce3+ yellow phosphor greatly decreased the correlated color temperature (CCT) from 6255 to 3517 K while significantly improving the color rendering index (CRI) from 72.5 to 87.5. It deserves to be mentioned that the brand-new matrix to phosphor in the present study can be extended to various niobium/tantalum oxyfluoride series, which is very helpful for developing and designing new red phosphors.

Bi 3+ , P O 4 3 − and B O 3 3 − doped Sc 0.73 Y 0.2 VO 4 : Eu 0 . 07 3 + phosphors were synthesized by solid state reaction at 1200 °C. The structure, morphology and luminescence properties were investigated. The synthesized phosphors show narrow particle distribution with average size around 2 μm. Under 365 nm excitation, integrate emission intensity increases after doping with Bi 3+ , P O 4 3 − and BO 3 3 − . The optimal doping concentrations are 1%, 20%, 10% for Bi 3+ , P O 4 3 − and BO 3 3 − , respectively. The thermal stability is greatly improved, especially for BO 3 3 − doped sample, whose intensity is about 92% of its original intensity even at 200 °C.