Nanosheets of an Organic Molecular Assembly from Aqueous Medium Exhibit High Solid-State Emission and Anisotropic Charge-Carrier Mobility

Abstract

The most studied 2D nanosheet is graphene whereas covalent organic frameworks and hexagonal boron nitride are the new addition to this family of nanomaterials.[1–3] These ultrathin, atomic, or sub-nanometer layers of 2D materials are in demand owing to their exceptional electronic, optical, thermal, and mechanical properties with high degree of anisotropy for applications in flexible optoelectronics, catalysis, bioimaging, and energy storage.[4–6] During the past two decades, supramolecular chemistry has been exploited for the creation of a variety of 0D, 1D, 2D, and 3D nanomaterials.[7–15] In most of the cases, spontaneous self-assembly of organic molecules leads to 1D structures, but preparation of the corresponding 2D sheets of a few layer thickness is a challenge.[16–19] 2D sheets of fluorescent molecules are required for display and sensing applications, however, organic 2D nanosheets having high fluorescence quantum yield is difficult to achieve due to the fluorescence self-quenching.[20,21] Another important requirement of organic 2D and 3D materials is high anisotropic charge-carrier mobility which is useful for the fabrication of organic field-effect transistors (OFETs) and organic solar cells.[22,23] Therefore, for flexible organic electronics, it is necessary to have a few layered 2D sheets with high fluorescen