Hydrothermal Synthesis and Photoluminescent Properties of YBO3:Eu3+ Nanophosphor Under Ultraviolet and Vacuum Ultraviolet Excitation

YBO3:Eu3+ Nanophosphors were prepared by hydrothermal reaction (HR) with different reaction times. When the reaction times increased, the grain sizes of phosphor did not change obviously, but the particle size, morphology, and aggregation state were different. This transformation has influenced luminescent properties. The change trends of luminescent intensity under ultraviolet (UV) and vacuum ultraviolet (VUV) excitation are almost contrary: the nanophosphor that has better intensity in UV region is lower in the VUV region and vice versa. The emission under UV excitation decreases first and increases later as time increases. However, the emission under VUV excitation increases first and decreases later. In the UV region, orange emissions (at 592 nm) are higher than red emissions (at 611 nm), but in VUV regions, red emissions are higher. All results indicated that luminescence properties of nanophosphors in VUV regions differ greatly from those of nanophosphors in UV regions. In a certain nanoscale, the decreased particle size will lead to enhanced luminescence under VUV excitation but weaker luminescence under UV excitation. The related phenomena and possible explanations are also discussed.