Effects of activated Sr²⁺ ion content on strong blue-emitting Ca₂Sb₂O₇ materials for high-quality WLED devices

In this report, the luminescent performances of the self-host blue-emitting Ca₂Sb₂O₇ materials were investigated in terms of the sintering temperature and the dopant Sr²⁺ ion content. The emission intensity was enhanced with an increase of the sintering temperature as well as the lattice parameters. After doping the Sr²⁺ ions (>1.2 mol%), the emission spectra of Ca₂Sb₂O₇ materials would be redshifted. The blue-emitting color (Ca₂Sb₂O₇) turned into greenish-blue (Sr²⁺@1.6 mol%) and green (Sr²⁺@2 mol%) colors in sequence. In light of these interesting findings, the crystal structure, elemental composition, morphology, thermal stability, luminescent dynamics, luminescent efficiency, etc were investigated and compared. Finally, the mini-white lighting-emitting diodes (WLEDs) based on the blue-emitting Ca₂Sb₂O₇, greenish-blue-emitting Ca_0.4Sr_1.6Sb₂O₇, and green-emitting Sr₂Sb₂O₇ phosphors were fabricated by mixing commercial phosphors (CP). Especially, the Ca₂Sb₂O₇-CP-WLED and Sr₂Sb₂O₇-CP-WLED devices exhibited a warm white light with good correlated color temperature (<3200 K) and excellent color-rendering index (>88). All the above results suggested that the self-host emitting materials of Sr²⁺ activated Ca₂Sb₂O₇ with color-tunable properties could be very promising for solid-state lighting applications.