“…23 It should be noted that nanocrystals are more chemically active than bulk materials in the solid-state reaction to convert the reactant into the product. 24 The electrospray technique produces size-selected and highly dispersive nanocrystals, [25][26][27] such as nanostructure oxide ceramic powders, [28][29][30] for use in light emitting diodes, 31 fuel cells 32,33 and solar cells. 34,35 In other words, the electrospray method could be a suitable and easy process to deposit small solidied crystals of the appropriate dimensions for halide exchange, thus enabling phase transformation in the solid-state reaction to prepare the perovskite active layer on the substrate.…”