Parafilm Enabled Rapid and Scalable Delamination/Integration of Graphene for High-Performance Capacitive Touch Sensor

The high electrical conductivity and bendability of graphene makes it versatile for flexible electronic sensor applications. The fabrication of such flexible sensors necessitates two important prerequisites: defect-free transfer of graphene to a flexible substrate and creating appropriate patterns without altering graphene's inherent properties. Here, a potentially rapid and scalable method to delaminate graphene non-destructively from a metal substrate by using flexible parafilm is reported. This method allows not only the scalable transfer of continuous graphene, but also the realization of graphene patterns on the parafilm substrate. Graphene on parafilm showed negligible doping effect with high room temperature carrier mobility exceeding 6 x 103 cm2 V-1 s-1 for a centimeter-scale sample. Using parafilm as a substrate-cum-dielectric medium, a proof-of-concept capacitive touch sensor (CTS) arrays is demonstrated without the use of lithography, by simple cross-assembling and mild heating. The graphene sensor thus realized in its simplistic device configuration had an enhanced sensitivity of 43% when touch and release cycles are performed on the device. The nearly non-destructive and user-friendly route for directly integrating graphene with a flexible substrate is expected to play a potential role in the design of graphene-based flexible electronics. A proof-of-concept graphene-based capacitive touch sensor (CTS) array is being fabricated without the use of lithography through a simple transfer process using parafilm. The parafilm serves as both a release layer and flexible substrate, enabling graphene transfer with a near-unity transfer yield. The resulting graphene-based CTS demonstrates an overall sensitivity of 43% during touch and release cycles on the device.image (c) 2024 WILEY-VCH GmbH