Jihan Shafiyah Z Tjenreng, Freygieon Ogiek Rizal Sukma, Dionysius J D H Santjojo, Istiroyah, Istiroyah Istiroyah, Sulaiman Wadi Harun, Masruroh
Reduced graphene oxide (rGO) films were successfully fabricated via hydrazine vapor reduction with durations of 60, 120, and 240 s using a water-based transfer approach. The transfer process exploits the surface tension of water to release GO films from mixed cellulose ester (MCE) membranes and deposit them smoothly onto glass substrates, producing homogeneous and residue-free layers. This study investigates the influence of reduction time on the morphological, structural, and optical evolution of rGO films. Characterization using TMS, FTIR, UV–Vis, Four-Probe, SEM, Raman, and TEM reveal that longer reduction durations enhance the removal of oxygen functional groups, restore the sp² carbon network. The film surface becomes smoother, with the roughness (Sa) decreasing from 692 to 397 nm, while the thickness increases due to uneven rearrangement and wrinkling of graphene sheets. FTIR and UV–Vis analyses confirm the progressive loss of oxygen functionalities and increased π-electron delocalization, which are consistent with reduced sheet resistance, higher extinction coefficients (k), and a darker film appearance. TEM images and SAED patterns reveal more crumpled graphene sheets and reduced interlayer spacing (d-spacing) in the (002) planes, indicating oxide removal and structural densification. These findings align with SEM observations showing a more porous morphology and an elevated C/O ratio in rGO compared to GO. Raman spectra exhibit an increased ID/IG ratio and a shift in the G band, reflecting enhanced defects and strain within sp² domains. Overall, the hydrazine vapor reduction method proved to be effective in forming uniform and well-printed rGO films with altered electrical and optical characteristics due to the restoration of the sp² carbon network. © 2026 The Author(s)
Department of Physics, Faculty of Mathematics and Natural Sciences, Universitas Brawijaya, Malang, Indonesia; Department of Physics, Faculty of Mathematics and Natural Sciences, Universitas Udayana, Bali, Indonesia; Department of Electrical Engineering, Faculty of Engineering, Universiti Malaya, Kuala Lumpur, Malaysia
