Determination of Handedness in a Single Chiral Nanocrystal via Circularly Polarized Luminescence

TL;DR

This paper introduces a method to determine the handedness of single chiral nanocrystals using circularly polarized luminescence combined with machine learning, enabling high-accuracy spatial mapping of chirality.

Contribution

The study demonstrates a novel approach for identifying and mapping the handedness of individual nanocrystals with high precision, overcoming limitations of previous optical techniques.

Findings

Successful determination of nanocrystal handedness using circularly polarized luminescence.

High accuracy spatial mapping of nanocrystal chirality achieved with machine learning.

Potential application in studying symmetry breaking in chiral materials.

Abstract

The occurrence of biological homochirality is attributed to symmetry breaking mechanisms which are still debatable1. Studies of symmetry breaking require tools for monitoring the population ratios of individual chiral nano-objects, such as molecules, polymers or nanocrystals. Moreover, mapping their spatial distributions may elucidate on the symmetry breaking mechanism. Recently, researchers have utilized differential scattering or circular dichroism microscopy to identify chirality on individual plasmonic nanostructures and inorganic nanocrystals. However, these measurements are prone to optical system artifacts. While luminescence is preferred for detecting single particle chirality, the typical low optical activity of chromophores limits its applicability. Here, we report on handedness determination of single chiral lanthanide based nanocrystals, using circularly polarized luminescence, with total photon count of $2\times 10^4$. We also utilize a machine learning approach for correlative microscopy to determine and spatially map handedness of individual nanocrystals with high accuracy. This technique may become invaluable in studies of spontaneous symmetry breaking in chiral materials.