Cryogenic Correlative Single‐Particle Photoluminescence Spectroscopy and Electron Tomography for Investigation of Nanomaterials

Abstract

Cryogenic single‐particle photoluminescence (PL) spectroscopy has been used with great success to directly observe the heterogeneous photophysical states present in a population of luminescent particles. Cryogenic electron tomography provides complementary nanometer scale structural information to PL spectroscopy, but the two techniques have not been correlated due to technical challenges. Here, we present a method for correlating single‐particle information from these two powerful microscopy modalities. We simultaneously observe PL brightness, emission spectrum, and in‐plane excitation dipole orientation of CdSSe/ZnS quantum dots suspended in vitreous ice. Stable and fluctuating emitters were observed, as well as a surprising splitting of the PL spectrum into two bands with an average energy separation of 80 meV. In some cases, the onset of the splitting corresponded to changes in the in‐plane excitation dipole orientation. These dynamics were assigned to structures of individual quantum dots and the excitation dipoles were visualized in the context of structural features.

Mesoscale Quantum-Confined Semiconductor Nanoplatelets through Seeded Growth

“…To confirm the presence of dispersed platelets, we perform correlative light and electron microscopy. Correlative imaging has been used previously on nanocrystals and 2D materials to study photophysical properties such as plasmonic behavior, catalysis, and defect emission in relation to their structure. − We adapt these methods here to perform photoluminescence (PL) mappings of our large NPLs. In Figure , we demonstrate that single NPL structures can be observed under conventional light and fluorescence microscopy (similar to their TMD counterparts).…”

Seeded Growth of Mesoscale Quantum-Confined Semiconductor Nanoplatelets

“…Correlative imaging has been used previously on nanocrystals and 2D materials to study photophysical properties such as plasmonic behavior, catalysis, and defect emission in relation to their structure. [52][53][54][55][56] We adapt these methods here to perform photoluminescence (PL) mappings of our large NPLs. In Figure 5, we demonstrate that mesoscale single NPL structures can be observed under conventional light and fluorescence microscopy (similar to their TMD counterparts).…”