Flexibility of Fluorinated Graphene-Based Materials.

Irina Antonova,Nadezhda Nebogatikova,Artem Ivanov,Nabila Zerrouki,Irina Kurkina

doi:10.3390/ma13051032

Abstract

The resistivity of different films and structures containing fluorinated graphene (FG) flakes and chemical vapor deposition (CVD)-grown graphene of various fluorination degrees under tensile and compressive strains due to bending deformations was studied. Graphene and multilayer graphene films grown by means of the chemical vapor deposition (CVD) method were transferred onto the flexible substrate by laminating and were subjected to fluorination. They demonstrated a weak fluorination degree (F/C lower 20%). Compressive strains led to a strong (one-two orders of magnitude) decrease in the resistivity in both cases, which was most likely connected with the formation of additional conductive paths through fluorinated graphene. Tensile strain up to 3% caused by the bending of both types of CVD-grown FG led to a constant value of the resistivity or to an irreversible increase in the resistivity under repeated strain cycles. FG films created from the suspension of the fluorinated graphene with a fluorination degree of 20–25%, after the exclusion of design details of the used structures, demonstrated a stable resistivity at least up to 2–3% of tensile and compressive strain. The scale of resistance changes ΔR/R0 was found to be in the range of 14–28% with a different sign at the 10% tensile strain (bending radius 1 mm). In the case of the structures with the FG thin film printed on polyvinyl alcohol, a stable bipolar resistive switching was observed up to 6.5% of the tensile strain (bending radius was 2 mm). A further increase in strain (6.5–8%) leads to a decrease in ON/OFF current ratio from 5 down to 2 orders of magnitude. The current ratio decrease is connected with an increase under the tensile strain in distances between conductive agents (graphene islands and traps at the interface with polyvinyl alcohol) and thickness of fluorinated barriers within the active layer. The excellent performance of the crossbar memristor structures under tensile strain shows that the FG films and structures created from suspension are especially promising for flexible electronics.

Highlights

The rapid growth in the popularity of the Internet of things, flexible, wearable and stretchable electronics, in the past decade has resulted in the strong progress in flexible electronics called flextronics [1]
Graphene and multilayer graphene films grown by means of the chemical vapor deposition (CVD) method were transferred onto the flexible substrate by laminating and were subjected to fluorination
In the case of the structures with the fluorinated graphene (FG) thin film printed on polyvinyl alcohol, a stable bipolar resistive switching was observed up to 6.5% of the tensile strain

Summary

Introduction

The rapid growth in the popularity of the Internet of things, flexible, wearable and stretchable electronics, in the past decade has resulted in the strong progress in flexible electronics called flextronics [1]. Two-dimensional (2D) layered crystals are believed to be the most promising candidates for flextronic applications, owing to their well-known features including the ultimate thickness scalability down to the atomic level, the flexibility increasing with the decreasing layer thickness and high intrinsic strain limit [11]. It was found that, in striking contrast to graphene, the mechanical properties of insulating hexagonal boron nitride (h-BN) (dielectric crystals which provided the high carrier mobility in graphene) are not practically changed with reducing the BN thickness [12]. This results in the limitation of BN applications for flextronics [13,14].

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Discussion

Conclusion