Article pubs.acs.org/JACS
Cite This: J. Am. Chem. Soc. 2017, 139, 14406-14411
Supramolecular Self-Assembly in a Sub-micrometer Electrodic Cavity: Fabrication of Heat-Reversible π‑Gel Memristor Lei Zhang, Songlin Li,‡ Marco A. Squillaci, Xiaolan Zhong, Yifan Yao, Emanuele Orgiu,*,§ and Paolo Samorì* University of Strasbourg, CNRS, ISIS UMR 7006, 8 Allée Gaspard Monge, F-67000 Strasbourg, France S Supporting Information *
ABSTRACT: The use of biomimetic approaches toward the production of nonsolid yet functional architectures holds potential for the emergence of novel device concepts. Gels, in particular those obtained via self-assembly of π-conjugated molecules, are dynamic materials possessing unique (opto)electronic properties. Their adaptive nature imparts unprecedented responsivity to various stimuli. Hitherto, a viable device platform to electrically probe in situ a sol−gel transition is still lacking. Here we describe the fabrication of a sub-micrometer electrodic cavity, which enables low-voltage electrical operation of π-gels. Thanks to the in situ supramolecular self-assembly of the π-gelator occurring within the cavity, we conceived a novel gelbased memristor whose sol−gel transition is reversible and can be controlled via heating and dc bias. This work opens perspectives toward the fabrication of a novel generation of nonsolid multiresponsive devices.
■
and exciton transport;6 (iii) the optimization of the interfaces with the device electrodes; and (iv) the utilization of the adaptive nature of gels and their capacity to respond to a multitude of external stimuli such chemicals, temperature, mechanical pressure, illumination, and so on, to ultimately realize multifunctional devices.7 Finally, the soft nature of gels is of paramount importance toward the emergence of the next generation of healable, adaptive, and flexible electronic devices.8 Usually, (nano)fiber aggregates forming a gel possess a diameter on the order of tens of nanometers and a length not exceeding a few micrometers.1 As a result, to fully exploit the unique single-fiber properties as well as to minimize the effect of interfiber connections and associated drop in charge transport, an ideal gel-based device should rely on interelectrodic gaps shorter than or comparable to the fiber length. Moreover, it is desirable that the electric field lines penetrate the bulk phase rather than concentrating at the surface or interface like in the case of dye-sensitized solar cells and ionic liquid gated devices. Hence, a major challenge facing π-gel electronics consists in exploiting a controlled electric field in a novel device configuration to tune the in situ supramolecular self-assembly. To address this challenge and make full use of supramolecular structures in nondry phase, here we have used cold-welding to form a novel electrodic cavity with a macroscopic lateral size and a sub-micrometer channel length. The latter enables low-voltage (
