Flex-Mode Mechatronic Functionality of Lead Iodide Hybrid Perovskite Systems

Abstract

The mechatronic functionality of lead iodide hybrid perovskite thin films grown on the flexible substrate is investigated via the study of current-perpendicular-to-plane charge transport modulation under flex-mode compressive and tensile strains (CS and TS) for multiple flexing cycles. It is shown that the transport is significantly, reversibly, and asymmetrically modulated. Typically, for a strain of 0.088% (0.23%), a remarkable current modulation of +196% (+393%) is achieved for compressive strain and -49% (-53%) for tensile strain at an applied potential of 1 V. For low levels of bending, the response is robust for a large number of bending cycles. The effects of the change of organic cation from methylammonium to formamidinium and the grain size on the response are also examined. A comparative study of the structural, morphological, and optical properties of the pristine sample and the samples subjected to multiple bending cycles is performed to understand and elucidate the possible mechanisms of the strain-induced changes in the transport properties.