GIWAXS using microbeam applied in halide perovskite films for high spectral resolution and mapping capability

Synchrotron-based grazing-incidence wide-angle X-ray scattering (GIWAXS) has become an essential tool for investigating halide perovskite film microstructures. Nevertheless, GIWAXS employing 100 µm X-ray beams inevitably suffers from footprint effects manifesting as diffraction peak broadening and spectral distortions. Herein, we demonstrate that microbeam GIWAXS (µ-GIWAXS) effectively mitigates these footprint effects, achieving enhanced spectral resolution and accuracy. By systematically tuning the grazing incidence angle, we quantitatively illustrated how the footprint length contributes to diffraction peak broadening in µ-GIWAXS. In addition, we optimize µ-GIWAXS data acquisition through beam-direction-perpendicular fly scanning, which improves data quality while preserving resolution and minimizing radiation damage at individual spots. Through extended exposure experiments, the effect of µ-GIWAXS microbeam irradiation on the structural stability of perovskite films was systematically evaluated. Furthermore, µ-GIWAXS enables spatial mapping of perovskite film microstructural characteristics including crystallinity, preferential crystal orientation, PbI₂ concentration and lattice strain - critical information for addressing inhomogeneity challenges in large-area perovskite devices. Given the growing demand in scalable perovskite optoelectronic applications, µ-GIWAXS warrants increased attention due to its dual advantages of superior spectral resolution and spatially resolved analysis capabilities.