Visualization of Surface Charge Carrier Diffusion Lengths in Different Perovskite Crystal Orientations Using 4D Electron Imaging

R. O. Nughays, C. Yang, S. Nematulloev, J. Yin, G. T. Harrison, J. Zhao, S. Fatayer, O. M. Bakr, O. F. Mohammed, Advanced Optical Materials (2023).

This work visualizes surface charge carrier diffusion in single-crystal perovskites using four-dimensional ultrafast scanning electron microscopy (4D-USEM). By tracking carrier motion in real space and real time in high spatiotemporal resolution, we demonstrate how orientation and termination govern diffusion behavior near the surface, revealing anisotropic transport pathways that are not accessible through conventional optical measurements.