Fengyu's paper on issues with UPS and KP measurements on metal halide perovskites appears in Advanced Energy Materials

The paper entitled "Ultraviolet Photoemission Spectroscopy and Kelvin-probe Measurements on Metal Halide Perovskite: Advantages and Pitfalls" outlines issues related to the proper treatment of UPS data to investigate the low density of states at the top of the valence band, as well as potential degradation of the material in vacuum under illumination.