Growth, crystal structure and IR luminescence of KSrY1–x Er x (BO₃)₂

A series of novel KSrY 1– x Er x (BO 3 ) 2 ( x = 0–1) phosphors that emit near-infrared radiation was synthesized using solid-state methods. Pure Y and Er crystals were grown using a KF flux via the top-seeded solution growth technique. In situ high-temperature single crystal X-ray diffraction, Raman spectroscopy and DFT calculations were used for characterization. Within the series, a polymorphic phase transition from space group P 2 1 / m to R 3 m was discovered between 550 and 600°C. The concentration dependence of the luminescence intensity was measured for the samples. A strong emission of Er 3+ electron transition 4 I 13/2 → 4 I 15/2 was detected within the 1529–1549 nm range, with the maximum observed for the KSrY 0.4 Er 0.6 (BO 3 ) 2 composition.