Using Electron Microscopy to Explore Solar Cell Interfaces: Microstructures, Efficiency, and Stability

Solar cell interfaces, including grain boundaries, twin boundaries, stacking faults, and phase boundaries, are the main nonradiative recombination and degradation sites and affect the photoelectric conversion efficiency and stability of solar cells, making it necessary to understand their fine structures and properties. Electron microscopy has provided micrometer/nanometer/atomic-scale structural information for investigating the microstructure of materials to unravel the structure–performance relationships of solar cells. Electron microscopy and related techniques have recently been used to investigate solar cell interfaces, but there has been no systematic summary of this research. In recent years, advances in technologies such as electron microscopy imaging, electron spectroscopy, in situ electron microscopy, and detectors have greatly expanded researchers' understanding of the interface properties of solar cells. This Review covers the research on the interfaces in perovskite/silicon/CdTe and Cu(In,Ga)Se2 (CIGS) solar cells using electron microscopy and provides prospects for further progress.