Synthesis and Optical Characterization of Mg1-xNixO Nanostructures

Abstract EN

An attempt has been made here to synthesize Mg1-xNixO (0.01≤x≤0.10) nano-powders via sol-gel process.

These powders are shown to possess an f.c.c.

(NaCl-type) structure with a typical lattice parameter of 4.228(2) Å for “x”=0.01 when decomposition of dried oxalate gel product is carried out at 600°C for 2 h in air.

Moreover, they exhibit (i) clusters/agglomerates of nanosize particles and (ii) high BET specific surface area (123.0–135.5 m2/g).

Also, the infrared absorption spectra reveal their strong affinity to water.

The UV-Vis absorption peaks appearing at ~202 nm, 296 nm, and 379 nm are associated with oxygen defect centres and correspond to the electronic transitions (i) A11g→T11u (1s→2px, 2py, or 2pz), (ii) A11g→E1 (1s→2px, or 2py) and (iii) A11g→A11g (1s→2pz), respectively.

The incorporation of Ni2+ ions causes some modifications in the energy levels and the optical absorbance characteristics.

The suppression of a strong broad emission peak at 440 nm and improvement of a weak band at ~400 nm in the photoluminescence (PL) spectrum arise due to decrease in population density of F22+ centres (or F+ dimmers) and emergence of additional F+ centres, respectively with increase in nickel content.