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Studies on the mechanical stretchability of transparent conductive film based on graphene-metal nanowire structures.

Lee MS, Kim J, Park J, Park JU - Nanoscale Res Lett (2015)

Bottom Line: Transparent electrodes with superior flexibility and stretchability as well as good electrical and optical properties are required for applications in wearable electronics with comfort designs and high performances.High electrical and optical characteristics, superb bendability (folded in half), excellent stretchability (10,000 times in stretching cycles with 100% in tensile strain toward a uniaxial direction and 30% in tensile strain toward a multi-axial direction), strong robustness against electrical breakdown and thermal oxidation were obtained through comprehensive study.We believe that these results suggest a substantial promise application in future electronics.

View Article: PubMed Central - PubMed

Affiliation: School of Materials Science and Engineering, Wearable Electronics Research Group, Low-Dimensional Carbon Materials Research Center, Ulsan National Institute of Science and Technology (UNIST), Ulsan, 689-798 Republic of Korea.

ABSTRACT
Transparent electrodes with superior flexibility and stretchability as well as good electrical and optical properties are required for applications in wearable electronics with comfort designs and high performances. Here, we present hybrid nanostructures as stretchable and transparent electrodes based on graphene and networks of metal nanowires, and investigate their optical, electrical, and mechanical properties. High electrical and optical characteristics, superb bendability (folded in half), excellent stretchability (10,000 times in stretching cycles with 100% in tensile strain toward a uniaxial direction and 30% in tensile strain toward a multi-axial direction), strong robustness against electrical breakdown and thermal oxidation were obtained through comprehensive study. We believe that these results suggest a substantial promise application in future electronics.

No MeSH data available.


Related in: MedlinePlus

Uniaxial and multi-axial stretchability of the hybrid structures. (a) The relative difference in the resistance of fabricated hybrid films on PDMS as a function of tensile strain toward uniaxial direction. (Here, AgNW networks were spin-coated on PDMS and a graphene layer was transferred onto the AgNW-coated PDMS.) (b) A graph for 10,000 times cyclic fatigue test of the hybrid film. Scale bar is 1 cm. (c) Relative change in the sheet resistance of hybrid nanostructures on PDMS according to tensile strain toward multi-axial direction. Scale bar is 1 cm.
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Fig5: Uniaxial and multi-axial stretchability of the hybrid structures. (a) The relative difference in the resistance of fabricated hybrid films on PDMS as a function of tensile strain toward uniaxial direction. (Here, AgNW networks were spin-coated on PDMS and a graphene layer was transferred onto the AgNW-coated PDMS.) (b) A graph for 10,000 times cyclic fatigue test of the hybrid film. Scale bar is 1 cm. (c) Relative change in the sheet resistance of hybrid nanostructures on PDMS according to tensile strain toward multi-axial direction. Scale bar is 1 cm.

Mentions: As the second form of hybrid sample, the AgNWs film was formed directly on PDMS using spin coating followed by transfer as an as-synthesized graphene layer onto the AgNW networks. The stretching testing was also done to examine the stretchable properties by elongating toward the uniaxial and multi-axial direction for the graphene-AgNW (spin-coated) hybrid electrode. Here, a multi-axial direction means the centrifugal force direction parallel with the plane of a fabricated hybrid films. The biaxial direction stretching of film has been reported [43] but that does not mean the centrifugal force direction stretching. After this hybrid sample was fixed to a mechanical apparatus, it was stretched toward the uniaxial direction and its Rs values were measured at specific stretching strains. Figure 5a shows the relative change in Rs according to increase of ε, and this graphene-AgNW (spin-coated) hybrid electrode can also be stretched up to 100% tensile strain without significant change. To investigate the durability against consecutive stretching and releasing, the Rs of the sample was measured during cyclic stretching tests (10,000 cycles at up to 100% tensile strain with a rate of 2.54 mm s−1) and it was almost constant without notable deformation, as plotted in Figure 5b. To confirm its further performance as a stretchable electrode, we assessed the Rs of our hybrid sample during stretching toward the multi-axial direction at up to 30% by using a homemade cylinder-shaped stretching stage, and the relative difference Rs was recorded at less than 5% (Figure 5c). Here, the maximum tensile strain was 30% due to the mechanical limitation of the stretching equipment. The mechanical stability of our hybrid nanostructures against bending (including extreme folding) and stretching is superior compared to ITO, which can be cracked by applying bending or tensile strain of approximately 1%.Figure 5


Studies on the mechanical stretchability of transparent conductive film based on graphene-metal nanowire structures.

Lee MS, Kim J, Park J, Park JU - Nanoscale Res Lett (2015)

Uniaxial and multi-axial stretchability of the hybrid structures. (a) The relative difference in the resistance of fabricated hybrid films on PDMS as a function of tensile strain toward uniaxial direction. (Here, AgNW networks were spin-coated on PDMS and a graphene layer was transferred onto the AgNW-coated PDMS.) (b) A graph for 10,000 times cyclic fatigue test of the hybrid film. Scale bar is 1 cm. (c) Relative change in the sheet resistance of hybrid nanostructures on PDMS according to tensile strain toward multi-axial direction. Scale bar is 1 cm.
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Fig5: Uniaxial and multi-axial stretchability of the hybrid structures. (a) The relative difference in the resistance of fabricated hybrid films on PDMS as a function of tensile strain toward uniaxial direction. (Here, AgNW networks were spin-coated on PDMS and a graphene layer was transferred onto the AgNW-coated PDMS.) (b) A graph for 10,000 times cyclic fatigue test of the hybrid film. Scale bar is 1 cm. (c) Relative change in the sheet resistance of hybrid nanostructures on PDMS according to tensile strain toward multi-axial direction. Scale bar is 1 cm.
Mentions: As the second form of hybrid sample, the AgNWs film was formed directly on PDMS using spin coating followed by transfer as an as-synthesized graphene layer onto the AgNW networks. The stretching testing was also done to examine the stretchable properties by elongating toward the uniaxial and multi-axial direction for the graphene-AgNW (spin-coated) hybrid electrode. Here, a multi-axial direction means the centrifugal force direction parallel with the plane of a fabricated hybrid films. The biaxial direction stretching of film has been reported [43] but that does not mean the centrifugal force direction stretching. After this hybrid sample was fixed to a mechanical apparatus, it was stretched toward the uniaxial direction and its Rs values were measured at specific stretching strains. Figure 5a shows the relative change in Rs according to increase of ε, and this graphene-AgNW (spin-coated) hybrid electrode can also be stretched up to 100% tensile strain without significant change. To investigate the durability against consecutive stretching and releasing, the Rs of the sample was measured during cyclic stretching tests (10,000 cycles at up to 100% tensile strain with a rate of 2.54 mm s−1) and it was almost constant without notable deformation, as plotted in Figure 5b. To confirm its further performance as a stretchable electrode, we assessed the Rs of our hybrid sample during stretching toward the multi-axial direction at up to 30% by using a homemade cylinder-shaped stretching stage, and the relative difference Rs was recorded at less than 5% (Figure 5c). Here, the maximum tensile strain was 30% due to the mechanical limitation of the stretching equipment. The mechanical stability of our hybrid nanostructures against bending (including extreme folding) and stretching is superior compared to ITO, which can be cracked by applying bending or tensile strain of approximately 1%.Figure 5

Bottom Line: Transparent electrodes with superior flexibility and stretchability as well as good electrical and optical properties are required for applications in wearable electronics with comfort designs and high performances.High electrical and optical characteristics, superb bendability (folded in half), excellent stretchability (10,000 times in stretching cycles with 100% in tensile strain toward a uniaxial direction and 30% in tensile strain toward a multi-axial direction), strong robustness against electrical breakdown and thermal oxidation were obtained through comprehensive study.We believe that these results suggest a substantial promise application in future electronics.

View Article: PubMed Central - PubMed

Affiliation: School of Materials Science and Engineering, Wearable Electronics Research Group, Low-Dimensional Carbon Materials Research Center, Ulsan National Institute of Science and Technology (UNIST), Ulsan, 689-798 Republic of Korea.

ABSTRACT
Transparent electrodes with superior flexibility and stretchability as well as good electrical and optical properties are required for applications in wearable electronics with comfort designs and high performances. Here, we present hybrid nanostructures as stretchable and transparent electrodes based on graphene and networks of metal nanowires, and investigate their optical, electrical, and mechanical properties. High electrical and optical characteristics, superb bendability (folded in half), excellent stretchability (10,000 times in stretching cycles with 100% in tensile strain toward a uniaxial direction and 30% in tensile strain toward a multi-axial direction), strong robustness against electrical breakdown and thermal oxidation were obtained through comprehensive study. We believe that these results suggest a substantial promise application in future electronics.

No MeSH data available.


Related in: MedlinePlus