(Invited) Autoperforation of 2D Materials for Generating Two Terminal Memresistive Janus Particles

Graphene and other 2D materials possess desirable mechanical, electrical and chemical properties for incorporation into or onto novel colloidal particles, potentially granting them unique electronic functions. However, this application has not yet been realized because conventional top-down lithography scales poorly for the production of colloidal solutions. Due to its inherent stochasticity, brittle fracture is seldom used as a fabrication method for materials at the nanometer scale. However, Griffith theory allows for the imposition of a specific strain field that can guide fracture along a pre-set design. Herein, we show that this autoperforation provides a means of spontaneous assembly for surfaces comprised of 2D molecular surfaces. Chemical vapor deposited mono- and bi-layer graphene, molybdenum disulfide, or hexagonal boron nitride (hBN) can autoperforate into circular envelopes when sandwiching a microprinted polymer spot of nanoparticle ink, allowing lift-off and assembly into solution. The resulting colloidal microparticles have two independently addressable, external Janus faces that we show can function as an intraparticle array of parallel, two terminal electronic devices. As an example, we print a 0.9 wt% black phosphorous (BP) nanoflake-in-polystyrene (PS) ink into mono-layer graphene sandwich particles, resulting in micro-particles possessing non-volatile, 15 bit memory storage via a spatially addressable memristor array throughout the particle interior. Such particles form the basis of particulate electronic devices capable of collecting and storing digital information in their environment. The 2D envelopes demonstrate remarkable chemical and mechanical stability for longer than 4 months of operation in aqueous buffer or even the highly acidic Human gastrointestinal environment at pH 1.5. Such particulate devices also survive aerosolization and re-collection for electronic interrogation. Autoperforation of 2D materials into such envelope structures allows precise compositing of particulate devices, extending nanoelectronics into previously inaccessible environments.