Nanoscale Molecular Building Blocks for Layer-by-Layer Assembly

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.