Abstract: This disclosure provides methods for forming a perovskite film. Exemplary methods can include the steps of forming an amorphous layer on a substrate disposed in a reaction chamber, covering at least a portion of the amorphous layer with a barrier that at least partially prevents the first metal, the second metal, oxygen atoms, or a combination thereof from being released during annealing and annealing the amorphous layer to form a perovskite film. Formation of the amorphous layer on the substrate disposed in a reaction chamber may be effected by introducing a first compound comprising a first metal; introducing an oxidizing agent; and introducing a second compound comprising a second metal.