Growth, crystal structure and IR luminescence of KSrY_1–x Er _x (BO₃)₂

A series of novel KSrY1–x Er x (BO3)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 P21/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 Er3+ electron transition 4I13/2 → 4I15/2 was detected within the 1529–1549 nm range, with the maximum observed for the KSrY0.4Er0.6(BO3)2 composition.