Anisotropic Photoluminescence in Perovskite Revealed by High-Framerate, Wide-Field, Polarization-Encoded Fluorescence Lifetime Imaging

Lead halide perovskites (LHPs) exhibit outstanding photophysical properties for optoelectronics; however, their poor photostability poses a significant challenge for characterization under continuous light exposure. Fluorescence lifetime imaging microscopy (FLIM) is a powerful tool for probing photogenerated charge carrier kinetics at a microscale level, yet conventional FLIM systems are limited by low frame rates (typically <10 fps), necessitating prolonged illumination that degrades LHPs before reliable data collection. In this study, we propose a novel high-speed FLIM system that enables the detection of local transient photoluminescence (PL) in a wide-field manner with a framerate of 98 fps and excellent temporal-spatial resolution (∼102 ps and ∼ 102 nm), which is approximately 1 order of magnitude higher than the reported value. By integrating a polarization-encoding module into the FLIM setup, we further reveal anisotropic PL emission with distinct polarization profiles from different microregions of the same LHP polycrystalline film. This approach establishes a robust platform for microscale investigation of the photophysical properties of LHPs.