(138e) Orientation Controlled Large Area Epitaxial PbI2 Thin Films with Tunable Optical Properties
AIChE Annual Meeting
2021
2021 Annual Meeting
Materials Engineering and Sciences Division
Materials for Quantum Science
Monday, November 8, 2021 - 1:54pm to 2:12pm
Lead Iodide (PbI2) as a layered material has emerged as an excellent candidate for optoelectronics in the visible and ultraviolet (UV) regime. Micrometer sized flakes synthesized by mechanical exfoliation from bulk crystals or by physical vapor deposition (PVD) have shown plethora of applications from low threshold lasing at room temperature to high performance photodetectors with large responsivity and faster response. However, large area, centimeter sized growth of epitaxial thin film of PbI2 with well controlled orientation has been challenging. Additionally, the nature of grain boundaries in epitaxial thin films of PbI2 remains elusive. Here, we use mica as a model substrate to unravel the growth mechanism of large area epitaxial PbI2 thin film. The partial growth leading to uncoalesced domains reveal the existence of inversion domain boundaries in epitaxial PbI2 thin films on mica. Combining the experimental results with first-principle calculations, we also develop an understanding of the thermodynamic and kinetic factors that governs the growth mechanism, which paves the way for the synthesis of high quality large area PbI2 on other substrates as well as heterostructures of PbI2 on single crystalline graphene. The ability to reproducibly synthesize high quality large area thin films with precise control over orientation and tunable optical properties could open up unique and hitherto unavailable opportunities for the use of PbI2 and its heterostructures in optoelectronics, twistronics, substrate engineering and strain engineering.