Voltage-Induced Transients in Methylammonium Lead Triiodide Probed by Dynamic Photoluminescence Spectroscopy

In this work, we use time-resolved photoluminescence (PL) spectroscopy, microscopy, and current measurements to characterize the slow transient responses of methylammonium lead triiodide (MAPbI 3 ) on a lateral interdigitated electrode device. By systematically varying the applied bias magnitude and electrode polarity, we observed distinct reversible and irreversible PL transient responses in the form of spectrally and spatially resolved PL quenching occurring over a range of 0.5–100 s. When the simultaneous current and the PL measurements were correlated, the reversible responses, present under all electric fields, were attributed to charge trapping, whereas the irreversible response, occurring above a nominal electric field between 1 and 5 kV cm –1, was attributed to ion migration. Thus, these results indicate that the slow transient response, and therefore hysteretic behavior, in MAPbI 3 devices is a complex response with contributions from both charge trapping and ion migration.