Investigation of the photoluminescence studies of ZnO: Dy³⁺ nanophosphors via different anionic group (BO₃ ³⁻, PO₄ ²⁻, and SO₄ ²⁻) substitutions

Abstract A series of ZnO-SG: x Dy 3+ ( x = 1 mol % and SG = BO 3 3− , PO 4 2− , and SO 4 2− ) phosphors were successfully synthesized through chemical combustion synthesis. The prepared phosphors were characterized by different characterization techniques such as x-ray diffraction (XRD), Scanning Electron Microscopy (SEM), Fourier-transform infrared spectroscopy (FTIR), and Ultraviolet-Visible spectroscopy (UV–vis), x-ray photoelectron spectroscopy (XPS), and photoluminescence (PL) spectroscopy, to study their crystal, morphological, optical, surface, and luminescent properties. The analysis of XRD patterns revealed that ZnO, ZnO: Dy 3+ , and ZnO-SO 4 :Dy 3+ crystallize in a ZnO hexagonal wurtzite crystal structure; however, for the borate and phosphate, there was a change of crystal structure to a Zn 4 B 6 O 13 cubic and Zn 2 P 2 O 7 monoclinic crystal structure, respectively. The EDS analysis of the prepared materials revealed the presence of all elements, and no unexpected peaks were observed. This was further confirmed by XPS surface analysis, which also revealed the oxidation states of the elements in these materials. Three PL characteristic emissions of Dy 3+ in the visible region with high intensities were observed for the borate and phosphate materials, which was not the case for the other samples. The three observed emissions at 484 nm, 575 nm, and 664 nm were attributed to Dy 3+ transitions from 4 F 9/2 to 6 H 15/2 , 6 H 13/2 , and 6 H 11/2 levels, respectively. A structural change has resulted in a shift from the orange-emitting phosphor material ZnO, which has a 93% colour purity, to yellow-emitting phosphor materials with colour purities of 88%, 78%, and 99% for ZnO-SO 4 :Dy 3+ , Zn 4 B 6 O 13 :Dy 3+ , and Zn 2 P 2 O 7 :Dy 3+ , respectively.