Hydrothermally grown Cu doped NiMnO ₃ perovskite nanostructures suitable for optoelectronic, photoluminescent and electrochemical properties

Abstract

Transition metal-based perovskites have emerged as highly promising and economically advantageous semiconductor materials due to their exceptional performance in optoelectronics, photovoltaic, photocatalysis, and photoluminescence. In this study, we employed a microwave-assisted hydrothermal process to produce a Cu-doped NiMnO ₃ nanocomposite electrode material. The appearance of a peak corresponding to the (110) plane with a 2θ value of 36.6° confirmed the growth of the rhombohedral NiMnO ₃ crystal structure. The presence of metal–oxygen bonds in NiMnO ₃ was confirmed through FTIR spectra. XPS validates the chemical composition, providing additional support for the results obtained from XRD and FT-IR analyses. FE-SEM affirmed the anisotropic growth of small sphere-like structures that agglomerated to form broccoli-like shapes. Cu doping modified the band gap, reducing it from 2.2 to 1.7 eV and enhancing its photoluminescent (PL) activity by introducing defects. The increase in PL intensity (visible light luminescent intensity) can be attributed to a concurrent rise in complex defects and the rate of recombination of electron–hole pairs. Finally, the electrochemical activity demonstrated the pseudo-capacitor behavior of the synthesized material, with capacitance values increasing as the copper (Cu) content in the parent lattice increased.