Multifunctional Two-Dimensional PtSe₂-Layer Kirigami Conductors with 2000% Stretchability and Metallic-to-Semiconducting Tunability

Abstract

Two-dimensional transition-metal dichalcogenide (2D TMD) layers are highly attractive for emerging stretchable and foldable electronics owing to their extremely small thickness coupled with extraordinary electrical and optical properties. Although intrinsically large strain limits are projected in them (i.e., several times greater than silicon), integrating 2D TMDs in their pristine forms does not realize superior mechanical tolerance greatly demanded in high-end stretchable and foldable devices of unconventional form factors. In this article, we report a versatile and rational strategy to convert 2D TMDs of limited mechanical tolerance to tailored 3D structures with extremely large mechanical stretchability accompanying well-preserved electrical integrity and modulated transport properties. We employed a concept of strain engineering inspired by an ancient paper-cutting art, known as kirigami patterning, and developed 2D TMD-based kirigami electrical conductors. Specifically, we directly integrated 2D platinum diselenide (2D PtSe2) layers of controlled carrier transport characteristics on mechanically flexible polyimide (PI) substrates by taking advantage of their low synthesis temperature. The metallic 2D PtSe2/PI kirigami patterns of optimized dimensions exhibit an extremely large stretchability of ∼2000% without compromising their intrinsic electrical conductance. They also present strain-tunable and reversible photoresponsiveness when interfaced with semiconducting carbon nanotubes (CNTs), benefiting from the formation of 2D PtSe2/CNT Schottky junctions. Moreover, kirigami field-effect transistors (FETs) employing semiconducting 2D PtSe2 layers exhibit tunable gate responses coupled with mechanical stretching upon electrolyte gating. The exclusive role of the kirigami pattern parameters in the resulting mechanoelectrical responses was also verified by a finite-element modeling (FEM) simulation. These multifunctional 2D materials in unconventional yet tailored 3D forms are believed to offer vast opportunities for emerging electronics and optoelectronics.

Two‐Dimensional Noble‐Metal Chalcogenides and Phosphochalcogenides

“…advanced that approach by growing the PtSe 2 layers directly on top of flexible polyimide foils suitable for high‐frequency applications. By patterning the PtSe 2 /polyimide membranes in a three‐dimensional kirigami fashion, Okogbue et al . built FETs with device stretchability above 2000 % as well as tunable electrical conductance and photoresponsivity.…”

Kirigami/origami: unfolding the new regime of advanced 3D microfabrication/nanofabrication with “folding”

“…Very recently, researchers have extended the concept and techniques of kirigami/origami to the regime of 2D materials 4,5,[95][96][97][98][99] , which has created an effective and promising platform to reshape 2D monolayers into 3D architectures through precise patterning, bending, folding, and twisting. Such 2D-to-3D transformation can enable unique properties very different from those of the original 2D materials, such as extremely large stretchability 99 , reversible photoresponsiveness 97 , and greatly enhanced light-matter interaction 96 . Moreover, it creates new opportunities for further development of self-actuated functional devices that may respond to mechanical forces, light or magnetic fields, thermal variations, or chemical modifications.…”

“…6f clearly show the advanced kirigami of WSe 2 heterostructures from four to nine layers. In device applications, Okogbue et al 99 recently developed a novel electrical conductor based on metallic 2D PtSe 2 /PI kirigami structures, which exhibited an extremely large stretchability of ∼2000% without compromising their intrinsic electrical conductance (Fig. 6g).…”

“…f WSe 2 kirigami 98 : SEM micrographs and AFM images of differently folded WSe 2 layers. g PtSe 2 kirigami 99 . Images reprinted with permission from: a, b ref.…”

Zweidimensionale Edelmetallchalkogenide und ‐phosphochalkogenide

“…entwickelten diesen Ansatz weiter, indem sie PtSe 2 ‐Lagen direkt auf flexibler Polyimid‐Folie wachsen ließen, was für Anwendungen im Ultrahochfrequenzbereich geeignet ist. Durch die Strukturierung der PtSe 2 /Polyimid‐Membranen in einer dreidimensionalen Kirigami‐Art haben Okogbue et al . FETs mit Dehnbarkeiten von über 2000 % hergestellt, deren elektrische Leitfähigkeit und Photoresponsivität genau eingestellt werden konnte.…”