An Excitation Navigating Energy Migration of Lanthanide Ions in Upconversion Nanoparticles. Issue 9 (21st January 2020)

• Record Type: Journal Article
• Authors: Lei, Zhendong; Ling, Xiao; Mei, Qingsong; Fu, Shuai; Zhang, Jing; Zhang, Yong
• Is Part Of: Advanced materials. Volume 32:Issue 9(2020)
• Page Start: n/a
• Page End: n/a
• Publication Date: 2020-01-21
• Subjects: anisotropic energy migration -- explosive residues -- fingerprints -- upconversion nanoparticles; Materials -- Periodicals; Chemical vapor deposition -- Periodicals; 620.11
• DOI: 10.1002/adma.201906225
• Languages: English
• ISSNs: 0935-9648

Abstract

Abstract: Upconversion nanoparticles (UCNPs) doped with lanthanide ions that possess ladder‐like energy levels can give out multiple emissions at specific ultra‐violet or visible wavelengths irrespective of excitation light. However, precisely controlling energy migration processes between different energy levels of the same lanthanide ion to generate switchable emissions remains elusive. Herein, a novel dumbbell‐shaped UCNP is reported with upconverted red emission switched to green emission when excitation wavelength changed from 980 to 808 nm. The sensitizer Yb ions are doped with activator Er ions and energy modulator Mn ions in NaYF4 core nanocrystal coated with an inner NaYF4 :Yb shell to generate red emission after harvesting 980 nm excitation light, while an outer NaNdF4 :Yb shell is coated to form a dumbbell shape to generate green emission upon 808 nm excitation. Such specially designed UCNPs with switchable green and red emissions are further explored for imaging of latent fingerprint and detection of explosive residues in the fingerprint simultaneously. This work suggests a novel research interest in fine‐tuning of upconversion emissions through precisely controlling energy migration processes of the same lanthanide activator ion. Furthermore, use of these nanoparticles in other applications such as simultaneous dual‐color imaging or orthogonal bidirectional photoactivation can be explored. Abstract : Energy migration of a single lanthanide activator ion in a novel dumbbell‐shaped upconversion nanoparticle is navigated along the favored electronic transitions pathway at specific excitation wavelengths, resulting in orthogonal emission properties. Such specially designed nanoparticles are further explored for simultaneous imaging of latent fingerprints and analysis of trace amounts of explosive residues in fingerprints.