Highly Oriented, Thin Pb Halide Perovskite Films from Single Source, CW Laser Vacuum Deposition

Pulsed laser deposition (PLD) is a well-established thin-film deposition technique for pure inorganic materials with high melting points. However, with the typical high energy (also very high time-averaged power) pulsed lasers used, it is quite challenging to deposit organic-inorganic hybrid materials like halide perovskites (HaPs) without decomposing their organic components and thus losing the stoichiometry. We report that thin stoichiometric HaP films can be deposited by 3-4 orders of magnitude lower time-averaged power <i>continuous wave</i> laser illumination of a corresponding HaP bulk material as a target. The CW deposition is solvent-free, occurs at room temperature, and needs only low vacuum. The method gives smooth, well-oriented thin films of various HaPs (explored here are MAPbBr₃, MAPbI₃, FAPbBr₃, BA₂PbI₄), making it promising for a scalable technology. Overall, the possibility of growing well-crystallized HaP thin films on any substrate without <i>in situ</i> and/or <i>ex situ</i> thermal treatments, using a single stoichiometric target, are attractive features of this CW deposition process.