Fig. 2: Studies on the electric-field in a CF3-PBAPy monolayer.
From: Confining iodide migration with quantified barrier for durable perovskite solar cells

a Spatial distribution of the electrostatic potential of the CF3-PBAPy molecule. b Kelvin probe force microscopy (KPFM) images of perovskite, perovskite/HfO2 and perovskite/HfO2/CF3-PBAPy films. The Rq value is the root mean square of the surface potential. Scale bar is 1 μm. c Changes of work function after depositing HfO2/CF3-PBAPy layer based on the parameters derived from KPFM images.