Yonsei Advanced Science Institute

Ultrathin molecular films can be used as building blocks to enable rational design of functionalities at the molecular level. A versatile and scalable approach to fabricate transfer‐compatible ultrathin molecular films with a broad range of physiochemical properties is reported. Different molecules in layers of uniform nanoscale thickness are deposited on monolayer hexagonal boron nitride (ML h‐BN) film. Initially, the deposited molecules form islands due to limited molecular diffusion during deposition on ML h‐BN, but postannealing effectively transforms them to the thermodynamically preferred film structures. Ultrathin building blocks composed of ML h‐BN and different molecules (C60, pentacene, C44H32N2) are realized, then transferred layer‐by‐layer (L‐by‐L) to form materials with precisely controlled composition and thickness, including donor/acceptor superlattices. This approach can facilitate the integration of nanoscale molecules with different material platforms for advanced functionalities.