Promising color controllable phosphors CBSOCNy:Eu2+ with excellent thermal stability

Novel Ca1.96(B1-ySiy)(O3-yNy)Cl:0.04Eu2+ phosphors were designed and synthesized by introducing [Si4++N3−]/[B3++O2−] co-substitutions into Ca2BO3Cl:Eu2+ lattice. Fourier Transform Infrared Spectroscopy (FTIR) show that typical planar [BO3]3− units gradually transformed into [BO4]5− units with the increase of y, which was firstly realized in luminescence materials. Uneven expansion of cell parameters a,b, and c were confirmed by the combination of X-ray diffraction spectra (XRD) and results of Rietveld refinement. Structure variation caused smaller centroid shift (εc) and 5d energy level splitting (εcfs), inducing the narrowing of excitation spectra (y = 0 → y = 0.2, 168 → 144 nm) and blue-shift of emission spectra (y = 0 → y = 0.2, 582 → 525 nm). Excellent thermal stability (6% loss at 150 °C) was obtained, which resulted from more covalent bonding. Using the combination of representative sample CBSOCN0.2: 0.04Eu2+ and red K2SiF6:Mn4+ in a blue LED driven lamp, white light with high CRI ~92.8 and color temperature closed to the summer sun (5770 K) was obtained. [Display omitted] •[Si4++N3−]/[B3++O2−] co-substitution was applied to synthesize the Ca2(B1-ySiy)(O3-yNy)Cl:Eu2+ series.•Luminescence color change from yellow to green with the increase of y.•Thermal stability of samples increased with the increase of y.•White light with high CRI can be synthesized by using the optimal sample CBSOCN0.2: 0.04Eu2+.