Growth, crystal structure and IR luminescence of KSrY 1-x Er x (BO 3 ) 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 P2 1 /m to R3m 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.