Offer a novel method for size appraise of NiO nanoparticles by PL analysis: Synthesis by sonochemical method

In this work, we will discuss the optical properties of NiO nanoparticles that we have investigated recently by photoluminescence (PL) spectroscopy. In particular, we will show the blue-shifts of PL, originating from the electron–hole recombination of the self-trapped exciton (STE), observed in smaller-sized NiO nanoparticles. To explain the size effect in relating to the STE PL shift, a question has been raised on whether it is appropriate to apply him quantum confinement (QC) theory usually used for the Mott-Winner type excitons in semiconductors to wide band-gap material, such as silica. Variations in several parameters and their effects on the structural (crystal size and morphology) properties of nanoparticles were investigated. Characterizations were carried out by X-ray diffraction (XRD), scanning electron microscopy (SEM), thermal stability (TGA and DTA), solid state UV and solid state florescent (PL).