Balanced strain-dependent carrier dynamics in flexible organic–inorganic hybrid perovskites†
Carrier dynamics of flexible organic–inorganic hybrid perovskite CH3NH3PbI3 (MAPbI3) films under various strains after photoexcitation were characterized by using time-resolved spectroscopy. The time-resolved photoluminescence study demonstrated that the charge carrier lifetime increases with increasing tensile strain, while it decreases with increasing compressive strain. This balanced optical response to tensile and compressive strains sheds light on the origin of ultra-stable optoelectric properties and overall film flexibility performance, which is further corroborated by transient absorption measurements. Moreover, the stability of flexible MAPbI3 films was enhanced by doping a tiny amount of rubrene molecules in an MAPbI3 precursor, without influencing the film structure or carrier dynamics. Our study provides new insights into the outstanding optoelectric properties and flexibility of the films and offers a novel method to improve the stability of organic–inorganic hybrid perovskite based flexible devices.