Optimizing structural, morphological, optical, and photon attenuation properties of AZO nanocrystals for radiation shielding

The study has been carried out to check the influence of different Al contents (0, 2, 4, 6, 8, and 10 at.%) in the structure and morphology of Al-doped ZnO nanocrystals (AZO NCs) by using X-ray diffraction (XRD), scanning electron microscopy (SEM), and energy dispersive X-ray analysis (EDXS), as well as the optical properties by using the UV–vis–NIR double-beam spectrophotometer within the wavelength of 300–1100 nm. XRD pattern shows a polycrystalline behavior and strong orientation and shifts in the peaks toward higher diffraction angles for AZO NCs with a hexagonal structure, and the crystallite size reduces from 28 ± 4 nm to 16 ± 4 nm as the Al concentration rises. SEM analysis revealed that the AZO NCs exhibit dense crystal grains with sharp edges. With increasing Al concentration, AZO NCs exhibited an increase in the optical bandgap from 3.16 eV to 3.57 eV. The study of the photon attenuation characteristics and radiation shielding properties of the AZO NCs has been assessed. For varying concentrations of Al, the corresponding mass attenuation coefficient (GMAC) and linear attenuation coefficient (GLAC) were determined for different energies of the incident photons. The calculated results showed that the GMAC value dropped with a rise in the Al concentration and a fall in photon energy. However, the GLAC value increased with the increasing population density. This further extends to studying the effect of higher Al contents on reducing the effective half-value layer (GHVL) based on the thickness of the shielding. Accordingly, the present work extends further to find the effective atomic number (Zeff) and mean free path (GMFP) with respect to correlations in photon energy and Al content. However, the trends differed across the energies for evaluating the exposure buildup factor (EBF). But, in general, the present findings from this study can be used to develop Pb-free, effective radiation shielding materials.