Self‐Assembled 2D Sheets of an Amphiphilic Sexiphenyl Exhibit Intense Polarized Blue Emission in the Solid State

Abstract

AbstractDistinct from inorganic 2D nanomaterials (e.g., graphene, MoS2, etc,), self‐assembled organic 2D materials are significant due to the unique advantages of fine structure tunability and functionality. Electronically and photofunctionally‐active compounds (e.g., pentacene, p‐sexiphenyl) are highly attractive for applications but are limited by difficult handling and the existence of only a few native structures of the compounds. Here, it is shown that a p‐sexiphenyl derivative incorporated into 2D multilamellar sheets with chromophores oriented in the layers exhibits a significant polarization of photoluminescence. Highly emissive, amphiphilic sexiphenyl with hydrophilic/hydrophobic groups self‐assembles at air–water interface with chromophore orientation in the resulting films being controlled by monolayer compression. Large‐area multilamellar structures with p‐sexiphenyl chromophores highly oriented against the 2D plane are prepared by consecutive film transfers. The 2D sheets exhibit significant polarization of photoluminescence with polarization ratio 0.8 between orthogonal in‐plane axes. Notably, multilamellar structures cannot be established for the same p‐sexiphenyl using thermotropic processing thus emphasizing the importance of the 2D sheet multilayer synthesis process. Amphiphile design can be applied for the tailored synthesis of large‐area multilayered 2D sheets and used to construct highly efficient light‐emitting devices.