Customizing H3Sb3P2O14 nanosheet sensors by reversible vapor-phase amine intercalation

Harvesting the large property space of 2D materials and their molecular-level fine-tuning is of utmost importance for future applications such as miniaturized sensors for environmental monitoring or biomedical detection. Therefore, developing straightforward strategies for the reversible and gradual fine-tuning of nanosheet properties with soft chemical intercalation methods is in high demand. Herein we address this challenge by customizing the host–guest interactions of nanosheets based on the solid acid H3Sb3P2O14 by vapor-phase amine-intercalation with primary alkylamines. Fine-tuning of the structural and chemical properties of the intercalated nanosheets is achieved by applying a two-step, post-synthetic intercalation strategy via the vapor phase. The method allows for the gradual and reversible replacement of one amine type by another. Hence, fine-tuning of the d-spacing in the sub-Å regime is accomplished and offers exquisite control of the properties of the thin films such as refractive index, polarity, film thickness and sensitivity towards solvent vapors. Moreover, we employ amine replacement to pattern thin films by locally resolved amine intercalation and subsequent washing, leading to spatially dependent property profiles. This process thus adds a new vapor-phase, amine-based variant to the toolbox of soft lithography.