Electric-Field-Induced Dynamic Electronic Junctions in Hybrid Organic–Inorganic Perovskites for Optoelectronic Applications

[Image: see text] Organic–inorganic metal halide perovskites have attracted great attention as optoelectronic materials because of their low cost, relative insensitivity to defects, and solution-processible properties. However, some of their properties, such as thermal instability, toxicity, and current–voltage hysteresis still remain elusive. Ion migration, which has been proven to be a thermal-activated process, is regarded as one of the major origins of the hysteresis and thus detrimental to the long-term stability of the optoelectronic devices. Nevertheless, by using the external electric field to pole the perovskite, ion migration would be possible to be utilized to create dynamic electronic junctions. In this paper, electric-field-induced dynamic electronic junctions have been manipulated for photodetection and energy harvesting through the ion migration under external electric field. Ion-migration-induced p–n or n–p junction has been successfully created via tuning the polarity of the external applied voltage, which is used for photodetection with a relatively fast response. By freezing out of the nonuniformly distributed ions after migration at low temperature, we demonstrate that the ion-migration-induced dynamic junctions can function as an energy harvesting device with an external quantum efficiency of 20%.