Optical characteristics of Tb-doped InBO _3 nanocrystals

摘要

InBO _3 nanocrystals doped with Tb ~(3+) ions are prepared via the sol-gel method. The structure, morphology, and optical properties of the nanocrystals are characterized by X-ray diffraction, high-resolution transmission electron microscopy, field-emission scanning electron microscopy, and photoluminescence analysis. The results show that a hexagonal InBO _3 phase forms at above 650 °C. A second phase of In _2O _3 begins to appear with Tb doping of over 3 mol. The ~5D _4→ ~7F _5 (553 nm) transitions of Tb ~(3+) ions in the InBO _3 host are observed at 2 mol. The decay time of Tb-doped InBO _3 nanocrystals is about 2.1 ms. For Tb-doped InBO _3 nanocrystals excited at 237 nm and 553 nm wavelengths, the 2 mol doping level yields the highest saturation of green emission. The emission shifts from green to yellow when the doping concentration is increased from 1 to 6 mol, due to the ~5D _4→ ~7F _5 transition.