Fig. 1
Doctor blading and doping of perovskite films by F4TCNQ. a Schematic illustration of a doctor-bladed perovskite film and the chemical structure of F4TCNQ dopant. b Cross-sectional SEM image of the MAPbI3 film deposited directly onto ITO glass via bladed coating at 150 °C, showing the film thickness of around 500 nm. Topography KPFM images of c, f MAPbI3, d, g F4TCNQ-doped MAPbI3, and e, h F4TCNQ solid-diffused MAPbI3 films. CPD represents the contact potential difference between the tip and sample’s surface. i Surface potential profiles of different perovskite films as indicated. j Schematic illustration of the energy diagram and electron transfer process for MAPbI3:F4TCNQ blends
