Recent progress on advanced transmission electron microscopy characterization for halide perovskite semiconductors

Abstract

Halide perovskites are strategically important in the field of energy materials. Along with the rapid development of the materials and related devices, there is an urgent need to understand the structure–property relationship from nanoscale to atomic scale. Much effort has been made in the past few years to overcome the difficulty of imaging limited by electron dose, and to further extend the investigation towards operando conditions. This review is dedicated to recent studies of advanced transmission electron microscopy (TEM) characterizations for halide perovskites. The irradiation damage caused by the interaction of electron beams and perovskites under conventional imaging conditions are first summarized and discussed. Low-dose TEM is then discussed, including electron diffraction and emerging techniques for high-resolution TEM (HRTEM) imaging. Atomic-resolution imaging, defects identification and chemical mapping on halide perovskites are reviewed. Cryo-TEM for halide perovskites is discussed, since it can readily suppress irradiation damage and has been rapidly developed in the past few years. Finally, the applications of in-situ TEM in the degradation study of perovskites under environmental conditions such as heating, biasing, light illumination and humidity are reviewed. More applications of emerging TEM characterizations are foreseen in the coming future, unveiling the structural origin of halide perovskite’s unique properties and degradation mechanism under operando conditions, so to assist the design of a more efficient and robust energy material.

Unveiling Electron Dose-Induced Phase Decomposition and Energy Kinetics in Cu-Doped CsPbI3 Nanocrystals

“…An enlarged image of the distortion, enhanced with false colors with the overlay of atomic positions (Figure S7b), clearly depicts the tilting of the PbI 6 4– octahedra, which marks the influence of the electron dose on the atoms. Due to the large influx of electrons, a high electric field is created that attracts the electron-deficient I – and Pb 2+ ions, which tend to leave the perovskite lattice. , This leads to the stretching of the Pb–I bonds, as presented in Figure S7b. It is imperative to state that the distribution of energy at different points within a lattice is a stochastic process, with minute variations in the amount and timing of energy imparted by the impinging electrons.…”

Unraveling the Microstructure of Inorganic Halide Perovskites during Thermally Driven Phase Transition and Degradation

“…In situ transmission electron microscopy (in situ TEM) meets the demands for atomic-scale imaging while heating. 24 In situ TEM was widely used to study the thermal degradation in perovskite solar cells. 25−27 However, it is quite challenging to perform in situ high-resolution TEM (HRTEM) for halide perovskites.…”

“…Therefore, a characterization method with high spatial and temporal resolution is urgently needed. In situ transmission electron microscopy (in situ TEM) meets the demands for atomic-scale imaging while heating . In situ TEM was widely used to study the thermal degradation in perovskite solar cells. − However, it is quite challenging to perform in situ high-resolution TEM (HRTEM) for halide perovskites. − First, halide perovskites are beam-sensitive, indicating that a prolonged TEM viewing can damage the sample severely and irreversibly .…”

Stereopsis‐Inspired 3D Visual Imaging System Based on 2D Ruddlesden–Popper Perovskite

“…[27][28][29][30][31] Moreover, the solution preparation method makes it easier to fabricate flexible large-area film devices. [32][33][34][35][36] Herein, we design a flexible 3D-VIS inspired by binocular stereopsis composed of two subsidiary sensors as shown in Figure 1c, adopting 2D-RPP as photoresponse material, polyimide (PI) film as a flexible substrate, and addressing circuit, of which the structure schematic is shown in Figure 1d. The prepared device arrays show good uniformity with a high switch ratio (≈10 4 ) and responsivity (250 A W −1 ), which are sufficient enough to meet the requirement of image sensing.…”