Electric field assisted spray coated lead free bismuth iodide perovskite thin film for solar cell application

Solution-processed Methylammonium iodo bismuthate (MBI) perovskite solar cell is fabricated by spray technique with changed applied voltages from 0 to 1000 V during the deposition of MBI thin film. The morphology and surface roughness of MBI films are influenced significantly by the electric field during film deposition. It is attributed to improve the atomization of spray droplets due to process of coulomb fission. The surface roughness of MBI film is reduced from 39 to 19 nm with increased applied voltages during the deposition from 0 V and 1000 V, respectively. A strong absorption band is observed similar to 500 nm for all MBI films. The MBI perovskite solar cell is showed enhancement in the efficiency with the maximum current density 2.33 mA/cm(2) at 1000 V applied voltage during the deposition. The improvement in photovoltaic characteristics with applied voltage during the film deposition is attributed to the formation of more uniform film with improved surface morphology and roughness, resulting in efficient electron transfer and reduced recombination of charge carrier at grain boundaries.