Modification of RuO2 nanosheet microstructure via hydrogen plasma treatment for transparent electrode applications

Although monolayer RuO 2 nanosheets exhibit semiconducting characteristics, their conductivity must be improved to enable application in transparent electrodes. In this study, RuO 2 nanosheet microstructures are modified through H 2 plasma treatment to reduce sheet resistance without deteriorating the optical characteristics necessary for flexible transparent electrode applications. Microstructural and chemical changes in the RuO 2 nanosheets are observed using monochromator Cs-corrected high-resolution transmission electron microscopy combined with electron energy loss spectroscopy. Single-crystalline RuO 2 nanosheets are transformed into nanometer-sized polycrystalline nanosheets. The phase-transformed polycrystalline RuO 2 nanosheets contain newly formed defects such as grain boundaries and O vacancies, which result in lower sheet resistances because these defects provide leakage-current paths in the semiconducting RuO 2 nanosheets. These defects are located parallel to the direction of light transmission. Consequently, transparency and haze do not significantly deteriorate after H 2 plasma treatment. These results indicate that the H 2 plasma creates a more stable O-vacancy row which alters the microstructure of the RuO 2 nanosheets. Our results demonstrate that H 2 plasma treatment can be widely used to fabricate two-dimensional material-based transparent electrodes. • RuO 2 nanosheets were plasma-treated after synthesis to improve their conductivity. • It induces the formation of O vacancies and grain boundaries through water removal. • Grain boundaries provide pathways for leakage currents, improving conductivity. • The method preserves the transmittance and haze of the nanosheets. • Efficient method for fabrication 2D materials for transparent electrodes.