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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。
Biological tissues have a strong absorption of light at 980 nm, limiting the biological applications of Yb / Er or Yb / Tm codoped Na YF4 upconverting nanoparticles. By Nd doping Na YF4: Yb, Er / Tm nanoparticles, nanoparticles that can generate fluorescence under laser excitation of 800 nm were obtained. Fluorescence spectra of Nd-doped nanoparticles with different morphologies show that the fluorescence spectra of NaYF4: Yb3 + 20%, Er3 + 2% @ NaYF4: Nd + 20% nanoparticles with core- The fluorescence intensity under the excitation is the highest, which is basically equivalent to the fluorescence intensity of NaYF4: Yb3 + 20% and Er3 + 2% nanoparticles under 980 nm laser excitation, and the intensity is stronger than that of NaYF4: Yb3 + 20% and Er3 + , Nd3 + 20% nanoparticles increased more than 600 times. The analysis shows that the quenching effect caused by Nd doping mainly comes from the interaction between Nd and the photosensitizer Yb, but not with the activator Er / Tm.