Structural and optical band gap engineering of Cu-Li co-doped NiO nanostructures for optoelectronic and energy applications

This study presents Cuand Li-co-doped nickel oxide (NiO) nanostructures that exhibit significant improvements in structural and optical properties. NiO samples, including pure, singly doped, and co-doped versions, are synthesized using the hydrothermal method. The structural, optical, and morphological characteristics are analyzed through X-ray diffraction (XRD), UV-visible spectroscopy, and scanning electron microscopy (SEM). XRD results revealed enhanced crystallinity in NiO films due to dual doping, making these materials promising for microelectronics applications. Refractive index and absorption coefficient demonstrated improvements in NiO with both single and co-doping. The band gap energy decreased from 3.50 eV for Cu-doped NiO to 3.34 eV for Cu, Li co-doped films. This reduction in band gap suggests that Cu and Li co-doping significantly enhances the electrochromic performance of the NiO samples. The increased absorbance in the NCL7 sample underscores the potential for fine-tuning dopant levels to further improve performance.