Mechanically Tunable Single-Walled Carbon Nanotube Films as a Universal Material for Transparent and Stretchable Electronics

Abstract

Soft, flexible, and stretchable electronic devices provide novel integration opportunities for wearable and implantable technologies. Despite the existing efforts to endow electronics with the capability of large deformation, the main technological challenge is still in the absence of suitable materials for the manufacturing of stretchable electronic circuits and devices with active (sensitive) and passive (stable) components. Here, we present a universal material, based on single-walled carbon nanotube (SWCNT) films deposited on a polydimethylsiloxane (PDMS) substrate, which can act as a material being both sensitive and insensitive to strain. The diverse performance of SWCNT/PDMS structures was achieved by two simple dry-transfer fabrication approaches: SWCNT film deposition onto the as-prepared PDMS and on the prestretched PDMS surface. The correlation between applied strain, microstructural evolution, and electro-optical properties is discussed on the basis of both experimental and computational results. The SWCNT/PDMS material with the mechanically tunable performance has a small relative resistance change from 0.05 to 0.07, while being stretched from 10 to 40% (stable electrode applications). A high sensitivity of 20.1 of the SWCNT/ PDMS structures at a 100% strain was achieved (strain sensing applications). Our SWCNT/PDMS structures have superior transparency and conductivity compared to the ones reported previously, including the SWCNT/PDMS structures, obtained by wet processes.

Recent Progress in Transparent Conductors Based on Nanomaterials: Advancements and Challenges

“…d,e) CNT based nanocomposite under strains of 10% and 100%. Reproduced with permission 57. Copyright 2019, American Chemical Society.…”

“…The conductivity of these conductors decreased during the first few stretching cycles but showed very stable conductivity in range of the initial strain with further cycles. Transferring CNT onto a prestrained elastomer is another approach to fabricate stable CNT TSC 36,57. In this technique, a wavy structure can be obtained without decreasing conductivity, and the conductivity becomes more stable as the flat structure is stretched to the prestrained range.…”

“…There are various techniques for filtrating and transferring nanomaterials, but vacuum filtration and transfer are major methods 34,43,46,47,53,57,64,65,72. The nanomaterial solution is filtrated through a filter membrane and resulting film is transferred to a target substrate using vacuum pressure ( Figure d).…”

“…The nanomaterial solution is filtrated through a filter membrane and resulting film is transferred to a target substrate using vacuum pressure ( Figure d). Note that this filtration step typically applies only to 1D nanomaterials such as CNT34,47,57 and MeNWs43,46,47,72 as 0D or 2D nanomaterials are hard to filtrate due to their shapes.…”

“…To improve the stretchability and electrical stability of TSCs, modifying structures has been occurred by transferring nanomaterials on a prestrained substrate36,47,49,55,57,69 or stretching and releasing after transfer 34,61. Transferring CNT on prestrained elastomer is reported as another approach to fabricate stable CNT TSC ( Figure ) 36,57. In this approach, wavy structures can be obtained without decreasing conductivity, and the conductivity becomes more stable as the material is stretched to its prestrained range.…”