Highly stretchable strain sensors based on Marangoni self-assemblies of graphene and its hybrids with other 2D materials

Abstract

Graphene and other two-dimensional materials (2DMs) have been shown to be promising candidates for the development of flexible and highly-sensitive strain sensors. However, the successful implementation of 2DMs in practical applications is slowed down by complex processing and still low sensitivity. Here, we report on a novel development of strain sensors based on Marangoni self-assemblies of graphene and of its hybrids with other 2DMs that can both withstand very large deformation and exhibit highly sensitive piezoresistive behaviour. By exploiting the Marangoni effect, reference films of self-assembled reduced graphene oxide (RGO) are previously optimized, the electromechanical behaviour being assessed after deposition onto different elastomers demonstrating the potential of producing strain sensors suitable for different fields of application. Hybrid networks are prepared by adding hexagonal boron nitride (hBN) and fluorinated graphene (FGr) to the RGO dispersion. The hybrid integration of 2D materials is demonstrated to become a potential solution to increase substantially the sensitivity of the produced resistive strain without compromising the mechanical integrity of the film. In fact, for quasi-static deformations up to 40%, a range of record GF values were obtained reaching up to 2000, while for cyclic deformations a stable performance is observed.

Exceptionally large fracture strength and stretchability of 2D ReS2 and ReSe2

“…Importantly, these values are also much larger than the maximal strain reported for silicon (∼2%) and larger than the maximal strain of polydimethylsiloxane (PDMS) and polyimide (PI) (∼7%) that are commonly used in flexible electronics. Recent studies demonstrated that the stretchability of 2D materials is attractive for many high-end applications, including flexible photodetectors, 56 electronic skin, 57 strain sensors, 58 and stretchable transistors. 59 Thus, the outstanding stretchability of ReS 2 and ReSe 2 alongside its optoelectronic properties makes them promising candidate materials for advanced flexible devices.…”

Machine Learning Assisted Enhancement in a Two-Dimensional Material’s Sensing Performance

“…This characteristic has been utilized in flexible electronics and wearable technology for strain-sensing purposes. For usage as an ultrasensitive, wide-area strain sensor in flexible electronics, graphene has been thoroughly researched. − TMDs have a significant piezoresistive effect, as does graphene, which is a single sheet of carbon atoms organized in a hexagonal lattice. It has been demonstrated that proof-of-concept strain sensors can track various states, such as the start and progression of crazes.…”

Recent developments in stretchable and flexible tactile sensors towards piezoresistive systems: A review

“…Paul et al 235 proposed a hybrid sponge of CNT and graphene to overcome this problem, as graphene sheets work as a bridge for discontinuous CNTs. The Maragoni effect is an interesting phenomenon utilized by Akouros et al 236 to solve the complex processing problem in the fabrication of two‐dimensional (2D) material‐based sensors, it has demonstrated promising results with GFs up to 2000.…”