Preparation, growth mechanism, size manipulation and near-infrared luminescence enhancement of β-NaYF4:Nd3+ microcrystals via Ca2+ doping†
Abstract
β-NaYF4:Nd3+ microcrystals have been prepared successfully by a facile hydrothermal route and characterized through structure analysis, photoluminescence spectroscopy and decay time. Their growth mechanism was profoundly discussed on the basis of different reaction time-dependent morphologies and phase evolution. More importantly, the near-infrared luminescence intensity at 1.06 μm was enhanced by about 3 times via doping Ca2+ into the NaYF4:Nd3+ microcrystal lattice. Meanwhile, the morphology and size of as-synthesized microcrystals were also manipulated by the Ca2+ doping strategy. The potent mechanism involving improvement of crystallinity along with the modification of the crystal field due to the introduction of Ca2+ ions was proposed to understand the enhanced near-infrared emission intensity of the β-NaYF4:Nd3+ microcrystals. The Ca2+-doped β-NaYF4:Nd3+ crystals with high performance have potential application in optical communication, laser application and biological deep-tissue imaging.