Polymer-grafted nanoparticle superlattice monolayers over 100 cm2 through a modified Langmuir-Blodgett method

Two-dimensional polymer/nanoparticle (NP) composite superlattice monolayers have attracted great attention, due to their applications in flexible optical, sensing, and electronic devices. The large-scale fabrication of these devices requires large-area superlattice monolayers. However, the preparation of large-area superlattice monolayers of polymer-grafted NP still faces great challenges. Herein, we report a modified Langmuir-Blodgett method for preparing large-area superlattice monolayers of polystyrene-grafted gold NPs ([email protected]). This method involves two key steps: pre-assembling the [email protected] on a liquid surface using mixed high/low-boiling-point solvent as the spreading solvent and then compressing the pre-assembled film in low-boiling-point solvent vapor. The discrete monolayer islands of [email protected] are formed in the pre-assembly process. During the surface compression process, the introduction of solvent vapor facilitates the fusion of [email protected] islands to form the continuous superlattice monolayers. Otherwise, discrete films with nonuniform thickness are obtained by compression without solvent vapor. This strategy enables the preparation of large superlattice monolayer films over 100 cm2, which are useful in the manufacture of microelectronic devices.