Effects of Cr3+ content on the structure and fluorescence properties of SiO2–Na2O–Y2O3–P2O5 glasses and glass-ceramics with Na3YSi2O7 crystal phase

•Cr2O3-doped SiO2–Na2O–Y2O3–P2O5 precursor glasses were prepared.•Transparent glass-ceramics containing Na3YSi2O7 phase were obtained.•Optimum Cr2O3 doping concentration and heat treatment regime were determined.•Cr2O3-doped glass-ceramics is not unique with excellent NIR properties. In this work, the Cr2O3-doped SiO2–Na2O–Y2O3–P2O5 precursor glasses were prepared by the melt-quenching method. A two-step heat treatment was used to obtain Cr2O3-doped glass ceramics with oxyapatite-silicate-type Na3YSi2O7 crystal phase. The optimum heat treatment schedule was determined to be heat-treated 660 °C/1 h + 760 °C/20 min by XRD and fluorescence spectra. Compared with precursor glasses, the luminescent properties of the Cr2O3-doped glass-ceramics containing Na3YSi2O7 crystals have been greatly improved. The optimum Cr2O3-doping amount was determined to be 0.4 mol%. Under the excitation of 490 nm, the glass-ceramics have a broad emission peak centered at 980 nm in the near-infrared region, which belongs to the 4T2→4A2 transition of Cr3+ ions. This work shows that the Cr2O3-doped glass-ceramic materials have the potential to be used as near-infrared luminescent materials in the fields of illumination display, bio-fluorescence imaging, solar cells, etc.