Boltzmann-Distribution-Driven Cathodoluminescence Thermometry in <i>In Situ</i> Transmission Electron Microscopy

Nanothermometry in <i>in situ</i> transmission electron microscopy (TEM) is useful for comprehending the functioning mechanisms of the heterogeneous matter through real-time observations. Herein, we introduce a Boltzmann-distribution-driven cathodoluminescence (CL) nanothermometry for <i>in situ</i> local temperature probing in TEM. The population distribution across the close-lying Stark sublevels of dysprosium ions in an yttrium vanadate matrix follows the Boltzmann distribution, enabling the use of the CL-intensity ratio as a thermometry over a wide temperature range of 103-435 K with a relative sensitivity exceeding 3% K^-1 and precision of ±2%. Superior to other CL-based thermometries, the present approach is independent of electron-beam parameters and dopant concentration, extending the robustness and applicability of CL-based nanothermometry in electron microscopy. We further demonstrate the real-time mapping of the temperature distribution across a TEM grid under laser irradiation.