Practice of electron microscopy on nanoparticles sensitive to radiation damage: CsPbBr3 nanocrystals as a case study

Tuan M Duong; Kshipra Sharma; Fabio Agnese; Jean-Luc Rouviere; Hanako Okuno; Stéphanie Pouget; Peter Reiss; Wai Li Ling

doi:10.3389/fchem.2022.1058620

Practice of electron microscopy on nanoparticles sensitive to radiation damage: CsPbBr₃ nanocrystals as a case study

Front Chem. 2022 Dec 20:10:1058620. doi: 10.3389/fchem.2022.1058620. eCollection 2022.

Authors

Tuan M Duong¹, Kshipra Sharma², Fabio Agnese², Jean-Luc Rouviere², Hanako Okuno², Stéphanie Pouget³, Peter Reiss¹, Wai Li Ling⁴

Affiliations

¹ Université Grenoble Alpes, CEA, CNRS, IRIG, SyMMES, STEP, Grenoble, France.
² Université Grenoble Alpes, CEA, IRIG, MEM, LEMMA, Grenoble, France.
³ Université Grenoble Alpes, CEA, IRIG, MEM, SGX, Grenoble, France.
⁴ Université Grenoble Alpes, CEA, CNRS, IBS, Grenoble, France.

Abstract

In-depth and reliable characterization of advanced nanoparticles is crucial for revealing the origin of their unique features and for designing novel functional materials with tailored properties. Due to their small size, characterization beyond nanometric resolution, notably, by transmission electron microscopy (TEM) and associated techniques, is essential to provide meaningful information. Nevertheless, nanoparticles, especially those containing volatile elements or organic components, are sensitive to radiation damage. Here, using CsPbBr₃ perovskite nanocrystals as an example, strategies to preserve the native structure of radiation-sensitive nanocrystals in high-resolution electron microscopy studies are presented. Atomic-resolution images obtained using graphene support films allow for a clear comparison with simulation results, showing that most CsPbBr₃ nanocrystals are orthorhombic. Low-dose TEM reveals faceted nanocrystals with no in situ formed Pb crystallites, a feature observed in previous TEM studies that has been attributed to radiation damage. Cryo-electron microscopy further delays observable effects of radiation damage. Powder electron diffraction with a hybrid pixel direct electron detector confirms the domination of orthorhombic crystals. These results emphasize the importance of optimizing TEM grid preparation and of exploiting data collection strategies that impart minimum electron dose for revealing the true structure of radiation-sensitive nanocrystals.

Keywords: HRTEM; STEM; cryo- TEM; electron beam damage; electron diffraction; graphene support film; lead halide perovskite; low-dose electron microscopy.