稀土离子掺杂LaPO4纳米结构材料形貌、物相的调控及发光性能

Controllable Morphology,Phase and Luminescent Properties of Rare Earth Ion-doped LaPO_4 Nano-structural Materials

利用水热合成技术,通过改变掺杂稀土离子的种类、掺杂浓度及添加剂的种类可实现LaPO4纳米结构材料形貌及物相的调控,同时还研究了合成材料的光致发光性能.结果表明:Ce3+离子掺杂浓度的增加可导致LaPO4纳米棒发生由单斜相向六方相的转变,而Tb3+离子掺杂浓度增加到相同的范围则不能够引起该相转变的发生;具有较小尺寸的LaPO4纳米棒易于"肩并肩"聚集形成纳米棒束;改变掺杂稀土离子的种类和浓度可调控纳米棒束的长度(150 nm～2.0μm),但对纳米棒束的直径影响不大(40～60 nm);添加剂的加入使纳米棒束更均一,对其相结构则基本没有影响;在紫外光激发下,单掺杂Ce3+或Tb3+离子的LaPO4纳米棒束分别表现出Ce3+或Tb3+离子的特征发射,由于Ce3+,Tb3+离子间存在有效的能量传递,Ce3+,Tb3+离子共掺杂的LaPO4纳米棒束表现出较强的Tb3+离子的绿光发射.

Rare earth ions（Ce3＋,Tb3＋） doped LaPO4 nano-structural materials were synthesized by hydrothermal treatment at 180 ℃ for 24 h,and characterized by X-ray diffraction（XRD）,scanning electron microscopy（SEM）,transmission electron microscopy（TEM）,photoluminescence（PL） spectra and kinetic decay curves.The morphology,phase and luminescent properties of the obtained samples can be controlled through altering the variety of additives and doped rare earth ions,and the doping concentration of rare earth ions.The results indicate that when the doping concentration is as low as 5 mol%,Ce3＋ or Tb3＋ ion-doped LaPO4 materials are composed of single-crystalline nanorods with the length of 200～550 nm and the diameter of 12～30 nm,and have monoclinic phase structure.These nanorods with small size trend to assemble through shoulder-by-shoulder to form the nanorod bundles.When the concentration of Ce3＋ ions increases from 5 to 30 mol%,the phase structure of LaPO4nanorods transforms from monoclinic to hexagonal phase,whereas the doping concentration of Tb3 ＋ ions at the same range can not result in the phase transformation.The length of the obtained nanorod bundles is at the range from 150 nm to 2.0 μm and the value can be controlled by altering the variety and the doping concentration of the doped rare earth ions,while the diameter of the nanorod bundles is mainly kept at 40～60 nm.The addition of different additives can improve the uniform feature of the obtained nanorod bundles and lead to the alteration of the length of these nanorod bundles.Under the excitation of ultraviolet light,Ce3＋ or Tb3＋ ion-doped LaPO4 nanorod bundles exhibit the characteristic emission of the corresponding doping ions,and the Ce3＋ and Tb3＋ ions co-doped samples exhibit strong green emission of Tb3＋ ions due to the efficient energy transfer between Ce3＋ and Tb3＋ ions.