Measuring 3D orientation of nanocrystals via polarized luminescence of rare-earth dopants

• Published in: Nature communications Vol. 12; no. 1; pp. 1943 - 10
• Main Authors: Kim, Jeongmo, Chacón, Reinaldo, Wang, Zijun, Larquet, Eric, Lahlil, Khalid, Leray, Aymeric, Colas-des-Francs, Gérard, Kim, Jongwook, Gacoin, Thierry
• Format: Journal Article
• Language: English
• Published: London Nature Publishing Group UK 29.03.2021; Nature Publishing Group; Nature Portfolio
• Subjects: 639/624/1107/510; 639/925/930/2735; Chemical Sciences; Crystals; Emission analysis; Emission measurements; Fluorescence; Humanities and Social Sciences; Luminescence; Magnetic dipoles; Material chemistry; Mechanical properties; multidisciplinary; Nanocrystals; Nanorods; Orientation; Phosphors; Rare earth elements; Science; Science (multidisciplinary); Viewing
• ISSN: 2041-1723; 2041-1723
• DOI: 10.1038/s41467-021-22158-4

Orientation of nanoscale objects can be measured by examining the polarized emission of optical probes. To retrieve a three-dimensional (3D) orientation, it has been essential to observe the probe (a dipole) along multiple viewing angles and scan with a rotating analyzer. However, this method requires a sophisticated optical setup and is subject to various external sources of error. Here, we present a fundamentally different approach employing coupled multiple emission dipoles that are inherent in lanthanide-doped phosphors. Simultaneous observation of different dipoles and comparison of their relative intensities allow to determine the 3D orientation from a single viewing angle. Moreover, the distinct natures of electric and magnetic dipoles originating in lanthanide luminescence enable an instant orientation analysis with a single-shot emission spectrum. We demonstrate a straightforward orientation analysis of Eu 3+ -doped NaYF 4 nanocrystals using a conventional fluorescence microscope. Direct imaging of the rod-shaped nanocrystals proved the high accuracy of the measurement. This methodology would provide insights into the mechanical behaviors of various nano- and biomolecular systems. Determining the orientation of nanoscale objects in three-dimensional space has typically required complicated optical setups. Here, the authors develop a simple method to retrieve the 3D orientation of luminescent, lanthanide-doped nanorods from a single-shot emission spectrum.