Co-/Cu-co-doped ZnO nanorods are synthesized by electrochemical deposition to investigate the effect of co-doping on their structural, optical, electronic, and electrochemical properties. XRD, Raman, SEM, and photoluminescence analyses reveal that Co/Cu incorporation modifies the ZnO lattice, increases defect-related states, and reduces the band gap from 3.11 to 2.15 eV. Density functional theory calculations further show that Co 3d and Cu 3d states appear near the Fermi level and contribute to the observed band-gap narrowing. Electrochemical measurements indicate that the co-doped nanorods exhibit the lowest charge-transfer resistance and the highest areal capacitance among the samples studied. Together, these results show that Co/Cu co-doping improves charge-transfer kinetics in ZnO nanorods and highlights co-doping as an effective strategy for tuning oxide electrodes for energy-storage applications.

In the present work, an essential advance in the preparation of novel nanocomposites based on functionalized V₂O₅ nanostructures with reduced graphene oxide by hydrothermal method, which has great potential for use in photocatalytic processes related to environmental remediation. XRD analysis confirmed V₂O₅ in an orthorhombic structure. SEM images showed transparent RGO layers well anchored onto the surface of the V₂O₅ with a homogeneous distribution. Raman spectroscopy further explained the hybridization and interaction between the components. The photocatalytic activity of Rhodamine-B in aqueous solutions has been studied upon irradiation with visible light. A high RhB degradation was obtained using the V₂O₅/RGO photocatalyst (82 %), compared to the degradation obtained with only V₂O₅ (60 %). First-principles Density Functional Theory (DFT) simulations reveal a strong interaction between V₂O₅ molecules and graphene surfaces, with an adsorption energy of −1.673 eV and a significant charge transfer of 0.367 e− to RGO. This interaction modifies the electronic structure, creating semi-metallic behavior near the Fermi level and enhancing catalytic activity through improved charge carrier dynamics and active sites for photocatalytic applications.

In this work, a ZnO nanowires/graphene nanohybrid was synthesized by a three steps approach. Copper substrates were covered with graphene by chemical vapor deposition, further ZnO nanowires were electrochemically deposited on the as grown graphene on copper and finally a transfer process was employed for moving the heterostructure onto a different substrate. A comprehensive structural analysis which included scanning electron microscopy, X-ray diffraction and Raman measurements revealed that the ZnO nanowires crystallize in wurtzite structure perpendicular to graphene, the process leading to the formation of a nanohybrid heterostructure. The band gap energy of the ZnO nanowires deposited on graphene was estimated to be 3.11 eV, as calculated from the reflectance spectrum analysis. The GGA-PBE+U within Grimme (DFT-D) approach was used to provide an accurate description of the interface structure in terms of electronic and optical properties, confirming that the decrease in the band gap energy of ZnO nanowires is caused by the interaction with the graphene surface. The findings of this study could serve as an experimental and theoretical reference for upcoming studies on ZnO NWs/Graphene nanohybrid-based optoelectronic applications.

We present a breakthrough in the development of novel nanocomposites based on reduced graphene oxide (RGO)-functionalized zinc oxide (ZnO) nanorods that hold exceptional promise for their use in white light emitting diodes (LEDs) and reliable UV photodetection. The nanorods had a pristine hexagonal wurtzite structure, as confirmed by XRD analysis. SEM images revealed sandwich-like nanocomposites with ZnO nanorods coated in reduced graphene oxide and embedded between two layers of RGO. The study also confirmed the hybridization and interactions between the layers using Raman measurements. The resulting nanocomposites displayed a lower band gap energy than ZnO and exhibited unique photoluminescence spectra with a white PL light. The photodetector based on RGO/ZnO/RGO sandwich structures demonstrated exceptional photoresponse, with higher photocurrent under UV illumination, making it highly promising for a wide range of optoelectronic applications. Overall, this study offers a novel and powerful approach to create nanocomposite structures with enhanced optical characteristics.

This study focused on investigating the optoelectronic properties of molybdenum trioxide (α-MoO₃) thin films using the atomic layer deposition (ALD) technique through different cycle numbers and theoretical investigation. Initial band gap calculations using standard DFT with GGA-PBE resulted in a value of 1.19 eV, which deviated significantly from experimental measurements. The GGA + U method with Hubbard U corrections was applied for the first time to improve the accuracy. This refinement led to a more precise band gap value of 3.09 eV, closely matching previously reported experimental data. The electronic parameters of the α-MoO₃ photodetector, such as ideality factor (n), barrier height (Φ₀), and series resistance (R_s), were analyzed using the thermionic emission theory and confirmed by Cheung and Nord's methods. The results demonstrated that the sample deposited with 100 pulses exhibited higher photodetector performance under UV illumination, despite having a lower R_s.