A clear signature of deep defects in at least the 1 ppm range is observed by low absorptance photocurrent spectroscopy. An eﬃciency drop, together with the defects, appears after minutes-long blue illumination and disappears after 1 h or more in the dark. This is caused by the lead halide residual phase inherently present in material prepared by the two-step method. Lead halide decomposes into metallic lead and mobile iodine, which diﬀuses into the perovskite, producing interstitial defects.
Contact: Jakub Holovský
Collaborating institutions: CTU Faculty of Electrical Engineering