单一稀土激活剂离子的正交上转换发光特性

Orthogonal luminescence properties of a single rare-earth activator ion doped upconversion nanoparticles

上转换发光纳米材料由于其特有的光学性质而一直备受关注,但常见的上转换发光纳米材料多为单色发光,为了实现上转换多色正交发光,同时避免多种掺杂剂离子的合成复杂性以及相互间的干扰性,利用Er3+的2H11/2,4S3/2→4I15/2能级跃迁产生的绿色发光和4F9/2→4I15/2能级跃迁产生的红色发光,设计出由Er3+单个激活剂离子掺杂的双激发上转换纳米颗粒。通过热分解法一步步合成出NaErF4:Yb(19.5%)/Tm(0.5%)@NaYF4:Yb(10%)@NaNdF4:Yb(10%)三层结构的上转换纳米颗粒。此方法合成出来的颗粒大小均一、结构稳定、分散性好。该双激发纳米颗粒能够在980 nm和808 nm的激发光下实现红色和绿色的正交发射光,且其单独发光不受影响。在980 nm激发下,红色光中650 nm处的发射峰强度大约能达到540 nm处发射峰的9.46倍;在808 nm激发下,绿色光中540 nm处发射峰强度大约能达到650 nm处发射峰强度的5.39倍。

Upconversion luminescence nanomaterials have attracted widespread attention owing to their special optical properties,while most of them emit single color luminescence.In order to achieve multicolor orthogonal upconversion luminescence and avoid the synthesis complexity and interference between multiple dopant ions,herein,we reported a novel orthogonal emissive upconversion nanoparticle,NaErF4:Yb(19.5%)/Tm(0.5%)@NaYF4:Yb(10%)@NaNdF4:Yb(10%),through thermal decomposition strategy step by step.This novel nanoparticle can give out green luminescence and red luminescence by the energy level transition of Er3+from 2H11/2,4S3/2→4I15/2 and 4F9/2→4I15/2 under the excitation light of 980 nm and 808 nm,respectively.The particles demonstrated uniform size,stable structure and excellent dispersibility.Under the excitation of 980 nm,the emission intensity at 650 nm of red luminescence was approximately 9.46 times more than the emission intensity at 540 nm.Under the excitation of 808 nm,the emission intensity at 540 nm of green luminescence was about 5.39 times more than the emission intensity at 650 nm.