Novel deep-red-emitting double-perovskite type Ca2ScNbO6:Mn4+ phosphor: Structure, spectral study, and improvement by NaF flux

A novel deep-red-emitting phosphor CaScNbO:Mn is prepared via a high-temperature solid-state reaction and its luminescent properties are systematically investigated. The results show that Mn-activated CaScNbO phosphors have broad absorption in ultraviolet region, and show bright deep-red emission at 692 nm. The optimal doping concentration, crystal-field strength, internal quantum efficiency, and mechanism of concentration and thermal quenching effects are discussed in detail. Moreover, NaF flux is screened out to improve both luminescent intensity and morphology of the phosphor. Finally, a red light-emitting diode (LED) lamp is fabricated with as-prepared CaScNbO:Mn phosphors and a 365 nm LED chip. The electroluminescence spectra show a good overlapping with phytochrome P and P absorbance. The results provided the as-synthesized CaScNbO:Mn phosphors a great potential in plant growth lighting.