The controlled growth of mixed dimensional perovskite structures, (C6H5CH2NH2)(CH3NH3)(n-1)PbnI3n+1, through the introduction of CH3NH3I molecule vapor into the two-dimensional perovskite C6H5CH2NH3PbI4 structure and its application in photovoltaic devices is reported. The dimensionality of (C6H5CH2NH2)(CH3NH3)(n-1)PbnI(3n+1) is controlled using the exposure time to the CH3NH3I vapor on the C6H5CH2NH3PbI4 perovskite film. As the stacking of the lead iodide lattice increases, the crystallographic planes of the inorganic perovskite compound exhibit vertical growth in order to facilitate efficient charge transport. Furthermore, the devices have a smaller band gap, which offers broader absorption and the potential to increase the photocurrent density in the solar cell. As a result, the photovoltaic device based on the (C6H5CH2NH2)(CH3NH3)(n-1)PbnI3n+1 perovskite exhibits a power conversion efficiency of 5.43% with a short circuit current density of 14.49 mA cm(-2), an open circuit voltage of 0.85 V, and a fill factor of 44.30 for the best power conversion efficiency under AM 1.5G solar irradiation (100 mW cm(-2)), which is significantly higher than the 034% of the pure two-dimensional BAPbI(4) perovskite-based solar cell. (C) 2017 Elsevier Ltd. All rights reserved.