Strong enhancement of electrical conductivity in two-dimensional micrometer-sized RuO₂ nanosheets for flexible transparent electrodes

Abstract

The enhancement in electrical transport properties of exfoliated individual RuO NSs was systemically investigated for their application in flexible electronics and optoelectronics. Decoration of Ag NPs on the surface of the RuO NSs provides donor electrons and dramatically increases the electrical conductivity of the monolayer RuO NSs by up to 3700%. The n-type doping behavior was confirmed via Hall measurement analysis of the doped RuO NSs. The layer number- and temperature-dependence of the conductivity were also investigated. Moreover, carrier concentration and mobility were obtained from Hall measurements, indicating that the undoped RuO NSs had ambipolar transport and semi-metallic characteristics. Moreover, the Ag-doped RuO NS multilayer films on polycarbonate substrates were demonstrated by the Langmuir-Blodgett assembly methods, showing one-third reduction in the sheet resistance and extraordinarily high bending stability that the change in the resistance was less than 1% over 50 000 cycles.

Modulation of Conductivity and Contact Resistance of RuO2 Nanosheets via Metal Nano-Particles Surface Decoration

“…We tested five-different monolayer and two bilayer nanosheets using the four-point probe measurement technique to determine the relationship between the surface doping process and the nanosheet thickness [ 28 ]. Although we observed differences in the conductivity of the nanosheets, the distributions of the conductivity values were consistent with the distributions observed in past studies using single-crystalline RuO 2 nanosheets [ 29 ]. Furthermore, the increase in the magnitude of conductivity was approximately constant with the nanosheets with the same number of layers, except for one nanosheet.…”

“…The interplanar d-spacing in the electron diffraction (ED) pattern and inter-atomic distance in STEM were equivalent to the d-spacing between the monolayer RuO 2 nanosheets obtained from our calculations [ 28 ]. The synthesis and exfoliation of RuO 2 nanosheets were described in detail elsewhere [ 28 , 29 , 31 ].…”

“…We employed surface charge transfer, using the surface decoration of metal nanoparticles, to modulate the electrical transport properties of RuO 2 nanosheets [ 29 , 30 ]. Copper (Cu) nanoparticles were decorated on the nanosheets using 0.05 M Cu acetate (Cu(OOCCH 3 ) 2 > 99.999%, Alfa Aesar, Haverhill, MA, USA) at room temperature for one day and washed with deionized water to remove the residual particles.…”

“…The crystal structure and physical properties of individual monolayer RuO 2 nanosheets were first studied using the potassium-intercalated RuO 2 [ 28 ]. Recently, researchers have demonstrated methods to increase electrical conductivity [ 29 ] and modulate the thermoelectric properties [ 30 ] of the exfoliated RuO 2 nanosheets through surface decoration treatments using Ag nanoparticles. This established the potential application of RuO 2 nanosheets as a flexible transparent conducting material.…”

Understanding the structural, electrical, and optical properties of monolayer h-phase RuO2 nanosheets: a combined experimental and computational study

“…Moreover, the RuO 2 NS films were very stable in the external electrical, mechanical, or Experimental transmission spectra of monolayer RuO 2 NS, CVD graphene, and a quartz substrate. The transmission spectra computed for distorted h-RuO 2 and t-RuO 2 and a transmission curve of distorted h-RuO 2 scaled by a factor of 0.9882 are presented optical field, showing a change in the resistance of less than 1% over 50,000 bending test cycles 36 . Figures 6b and S10 illustrate the optical transmission spectra of monolayer RuO 2 NSs and the locations used to obtain the spectra, respectively.…”