A novel deep red phosphor Ca14Zn6Ga10O35:Mn4+ as color converter for warm W-LEDs: Structure and luminescence properties

Currently, the non-rare-earth Mn4+-activated oxide red phosphor is of great interest as color converter for warm white light-emitting diodes (W-LEDs), owing to its admirable luminescent properties and low price. Herein, a novel blue-light activated Ca14Zn6Ga10O35:Mn4+ (CZG:Mn4+) phosphor, exhibiting strong red emission attributed to Mn4+:2Eg → 4A2g spin-forbidden transition in region of 650–750 nm under 462 nm excitation, is successfully synthesized through a traditional solid-state reaction route in air. Subsequently, the microstructure and luminescent performance of this red-emitting phosphor are discussed in detail. The crystal field strength (Dq) and the Racah parameters (B and C) are carefully calculated to estimate the nephelauxetic effect of Mn4+ suffering from the CZG host lattice. In addition, the concentration quenching and thermal quenching characteristics are also systematically investigated. After incorporating CZG:Mn4+ and commercial Y3Al5O12:Ce3+ (Ce:YAG) phosphors into a blue LED device, warm white light with high color rendering index and low correlated color temperature is successfully achieved. Therefore, the CZG:Mn4+ phosphor can serve as color converter for use in warm W-LED applications.