Magnetic-field-induced energy bandgap reduction of perovskite KMnF3†
Broad impact may be anticipated when an energy bandgap is varied substantially by a small change in the physical environment. Such possibility has now been discovered by the example of a perovskite structure of KMnF3 in this paper, where photoluminescence, X-ray diffraction, scanning electron microscope and conductivity measurements were conducted, and the bandgap reduced up to 20% when a small magnet was placed beneath the substrate. It was also found that the electrical conductivity increased in the meantime by more than 15 folds under the 0.6 Tesla field strength. Such reduction in perovskite bandgap and enhancement in the transport properties were also observed by us in other structures, such as CH3NH3PbI3 and CsPbBr3. These discoveries are expected to improve the device performance and accelerate the commercialization.