Optical and structural properties of Mo-doped NiTiO₃ materials synthesized via modified Pechini methods

Highlights: • Mo-doped NiTiO₃ materials were well prepared by a modified Pechini method. • Recombination rates of the materials were significantly inhibited by Mo doping. • Defect sites were generated by the substitution of Mo for Ni or Ti positions. • The generation of defect sites gradually decreased the grain sizes of the materials. • The surface areas of the materials were increased with decreasing the grain sizes. - Abstract: In this study, molybdenum (Mo)-doped nickel titanate (NiTiO₃) materials were successfully synthesized as a function of Mo content through a modified Pechini method followed by a solvothermal treatment process. Various characterization methods were employed to investigate the optical and structural properties of the materials. XRD patterns clearly showed that the NiTiO₃ structure maintained a single phase with no observed crystalline structure transformations, even after the addition of 10 wt.% Mo. In the Raman spectra and XRD patterns, peak positions shifted with a change in Mo content, confirming that the NiTiO₃ lattice was doped with Mo. On the other hand, Mo doping of NiTiO₃ materials changed their optical properties. DRS-UV demonstrated that the addition of Mo increased photon absorption within the UV region. Relaxation processes were inhibited by Mo doping, which was evident in the PL spectra. Structural properties of the prepared materials were studied via FE-SEM and HR-TEM. The measured surface area increased proportionally with Mo content due to a reduction in grain size of the materials.