Large-Area Alignment of Supramolecular Columns by Photothermal Laser Writing

Controlling the orientation of highly periodic supramolecular structures of small feature size (<5 nm) is the first step for potential applications in optoelectronics, membranes, and template synthesis. A new method, namely, laser photothermal writing, is introduced to direct the orientation of supramolecular columns over a large area. Supramolecular columns consisting of taper-shaped molecules with long aliphatic tail groups are aligned by a thermal gradient, which is induced by exposing a near-infrared laser beam to a graphene photothermal conversion layer. Intriguingly, the orientation of the supramolecular columns can be controlled in a facile manner by varying the laser scanning velocity and power. In contrast to previous methodologies for aligning supramolecular structures, this laser photothermal mechanism allows the directional and continuous alignment of supramolecular structures over an arbitrary large area with the easy control of laser irradiation. Besides, the laser process also enables area-selective orientation of the supramolecular structures for device-oriented nanopatterning.