Organic–inorganic
perovskites have attracted increasing
attention in recent years owing to their excellent optoelectronic
properties and photovoltaic performance. In this work, the prototypical
hybrid perovskite CH3NH3PbI3 is turned
into a ferromagnetic material by doping Mn, which enables simultaneous
control of both charge and spin of electrons. The room-temperature
ferromagnetism originates from the double exchange interaction between
Mn2+–I––Mn3+ ions. Furthermore, it is discovered that the magnetic field can
effectively modulate the photovoltaic properties of Mn-doped perovskite
films. The photocurrent of Mn-doped perovskite solar cells increases
by 0.5% under a magnetic field of 1 T, whereas the photocurrent of
undoped perovskite decreases by 3.3%. These findings underscore the
potential of Mn-doped perovskites as novel solution-processed ferromagnetic
material and promote their application in multifunctional photoelectric-magnetic
devices.