Significant and systematic impact of yttrium doping on physical properties of nickel oxide nanoparticles for optoelectronics applications

Abstract

The structural, optical, and dielectric properties of pure NiO and yttrium (Y) doped NiO (Y: NiO) were studied in the present article for optoelectronic application. The pristine and different concentrations of 1.0, 2.5, 5.0, 7.5, and 10 wt.% doped Y: NiO nanoparticles (NPs) were synthesized by flash combustion route. X-ray diffraction patterns (XRD), Raman spectroscopy and scanning electron microscopy (SEM) images were used to study the structural properties of as-prepared nanoparticles. The average crystallite sizes (29.8–6.7 nm) and grains size (159.2–17.9 nm) were found to be decreased with an increase in Y contents. The dislocation density (1.12–21.75 × 10−3 1/nm2), lattice strain (2.79–12.46 × 10−3) and surface area (29.48–131.13 cm2/g) were increased on increasing Y contents. Direct optical band gaps of prepared samples were estimated using the Tauc's relation in the range of 3.52–3.37 eV. Photoluminescent spectra of prepared samples exhibit spectra at 355 nm, 451–482 nm, and 493 nm emission bands, which confirm the existence of oxygen and nickel vacancies. The improvement in the dielectric constant (143), dielectric loss (1233), and loss tangent (8.67) were observed for 5.0 wt.% Y doped NiO from the dielectric analysis of the samples. The electrical conductivities of Y: NiO NPs were also improved compared to pure NiO NPs. The improvement in the optical and dielectric properties of NiO in the substitution of yttrium (Y) can be used for optoelectronics applications.