Nd^(3+)掺杂的NaYF_4∶Yb,Er/Tm上转换纳米颗粒的光谱分析

Research on Photoluminescence of Nd^(3+) Doped NaYF_4:Yb, Er/Tm Upconversion Nanoparticles

生物组织对980 nm波长的光有较强的吸收,限制了Yb/Er或Yb/Tm共掺的Na YF4上转换纳米颗粒在生物方面的应用范围。通过对Na YF4∶Yb,Er/Tm纳米颗粒进行Nd掺杂,获得可在800 nm波长的激光激发下产生荧光的纳米颗粒。对多种不同形貌的Nd掺杂纳米颗粒的荧光光谱的研究表明,具有核壳结构的Na YF4∶Yb3+20%,Er3+2%@Na YF4∶Nd3+20%纳米颗粒在800 nm激光激发下的荧光强度最高,基本上与Na YF4∶Yb3+20%,Er3+2%纳米颗粒在980 nm激光激发下的荧光强度相当,其强度比Na YF4∶Yb3+20%,Er3+2%,Nd3+20%纳米颗粒提高了600倍以上。分析表明,Nd掺杂导致的淬灭效应主要来自于Nd和光敏剂Yb之间的作用,而不是与活化剂Er/Tm之间的作用。

Strong absorption of 980 nm wavelength light by biological tissues results in the limited application of Yb/Er or Yb/Tm doped Na YF4 upconversion nanoparticles. 800 nm excited Na YF4∶Yb, Er/Tm nanoparticles doped with Nd3 ＋ions are reported. By comparing the photoluminescence spectra of different structured nanoparticles incorporated with Nd3 ＋ions, it is found that the emission intensity by 800 nm laser of core/shell structured Na YF4∶Yb3＋20%, Er3＋2%@Na YF4∶Nd3＋20% nanoparticles is the highest, which is close to the emission intensity of Na YF4∶Yb3 ＋20%, Er3 ＋2% nanoparticles excited by 980 nm laser. The emission intensity is enhanced by more than 600 times compared with that of Na YF4∶Yb3＋20%, Er3＋2%, Nd3＋20% nanoparticles. It is proved that the quench effect due to Nd incorporation is mainly related to the interaction between Nd3 ＋ions and the sensitizer Yb3＋ions, but not that between Nd3＋ions and the activator Er3＋/Tm3＋ions.