A formulation of methylammounium iodide (MAI), PbCl2 and PbI2 at a molar ratio of 1:1:4 (PbCl2:PbI2:MAI) in a DMF solvent. On processing, I201 ink can be used to create a CH3NH3PbI3-xClx perovskite film. The process recipe for I201 is optimised for glove box processing under a nitrogen atmosphere.
