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

• DOI: 10.1038/s41467-021-22158-4
• Publication Date: 2021-03-29T10:04:22Z
• Authors: Jeongmo Kim; Reinaldo Chacón; Zijun Wang; Eric Larquet; Khalid Lahlil; Aymeric Leray; Gérard Colas-des-...; Jongwook Kim; Thierry Gacoin
• Keywords: Science; Q; [CHIM.MATE]Chemical Sciences/Material chemistry; 02 engineering and technology; 0210 nano-technology; 530; Article; 620

AbstractOrientation 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 Eu3+-doped NaYF4 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.