Fig. 2.

Conductivities and photoluminescence lifetimes of neat or doped perovskite films. a Geometry for the lateral conductivity measurement: the perovskite films were 500 nm thick, with 1 mm gold (Au) electrodes separated by 100 μm. b J–V curves of neat or F4TCNQ-doped MAPbI₃ deposited on normal glass substrates, where the current was measured along the lateral direction. c TRPL decay curves of glass/MAPbI₃ and glass/MAPbI₃:F4TCNQ. PL lifetimes were calculated by single exponential fitting. d c-AFM setup. Topographic AFM images of e MAPbI₃ and g MAPbI₃:F4TCNQ films, with locations where the c-AFM tip measured the grain and GB currents. Local dark currents measured at the GBs and on the grains for the f MAPbI₃ film and h MAPbI₃:F4TCNQ film