Perovskite Pattern Formation by Chemical Vapor Deposition Using Photolithographically Defined Templates

Thin film fabrication is necessary to realize the device integration of organic–inorganic hybrid perovskites (OIHPs), and solution-based crystallization methods have been employed widely to this end. Despite the versatility of the solution approach, device fabrication using typical “top-down” lithography is generally incompatible with as-prepared OIHPs films because of the low stability of perovskites to polar solvents involved in the lithographic process. Moreover, solution-prepared perovskites usually exhibit irregular surface roughness, implying the existence of randomly oriented crystal domains with a large density of grain boundaries, which are ultimately detrimental to the material properties. Here, we report a patterning of CH 3 NH 3 PbI 3 (MAPbI 3 ) thin films using a photolithographically fabricated cross-linked copolymer template on Si or SiO 2 substrates via a chemical vapor deposition (CVD) method. Perovskite patterning is accomplished by growing PbI 2 precursor layers selectively on template patterns and subsequently converting to MAPbI 3 using CH 3 NH 3 I (MAI) in the vapor phase. We confirm that [0001]-oriented PbI 2 nanoplatelets nucleate primarily on a Si or SiO 2 surface and grow by surface diffusion from a polymer surface. The MAPbI 3 conversion process preserves the original pattern morphology through the vapor–solid intercalation of MAI. Prototype photodetector arrays based on MAPbI 3 patterns are also demonstrated. Our results highlight the advantages of the CVD patterning of perovskite materials in large-scale production for a range of optoelectronic applications.