Structural and luminescent properties of aluminum‒based nanophosphors

Abstract

This work presents the structural impacts of the crystalline micro and nanoparticles co-doped aluminum oxide on their thermoluminescent features. For this purpose, Ca9Al (PO4)7 with different Cr and Si concentrations was prepared and the best in TL-response in this batch was selected for further study which was Ca9Al (PO4)7: 2 Cr, 8 Si mol%. Additionally, Al2O3 co-doped with different dopants was synthesized. Al2O3: 0.005 (P, Ca, Cr, Si) mol% showed the higher TL-response in this batch and was selected for further study. The surface morphology and uniform distribution of the elements of the selected samples were confirmed using scanning electron microscopy (SEM) with Energy Dispersive X-ray scattering (EDX) analysis. X-Ray Diffraction (XRD) and transmission electron microscope (TEM) results reflected the existence of the nanoparticles structure with average sizes of 22.7 and 35.13 nm for Ca9Al (PO4)7: 2 Cr, 8 Si mol% and Al2O3: 0.005 (P, Ca, Cr, Si) mol%, respectively. Photoluminescence (PL) spectrum at λex = 304 nm shows emission at range of 370–600 nm and at 825 nm for both samples. Good linear dose-response relationships were found in dose range of 3 up to 20 Gy. But, the TL-response of Al2O3: 0.005 (P, Ca, Cr, Si) mol% structure was about 22 times higher than that of the Ca9Al (PO4)7: 2 Cr, 8 Si mol% one. Therefore, introducing P and Ca as a co-dopants with Cr and Si in Al2O3: P, Ca, Cr, Si highly increased its TL-response. This reflected the structural dependence of the studied samples on their TL-responses.