Speaker
Description
Zinc aluminate (ZnAl2O4) is a member of the spinel family which has attracted great research interest due to its diverse properties such as high fluorescence efficiency, hydrophobicity, high chemical, and thermal stability. These properties make it a suitable candidate for application such as in displays, magnetic refrigerators, catalysis, and light emitting diodes (LED). In this study, a well separated ZnAl2O4 doped with various Fe3+ ions were prepared using Pechini synthesis method. The particle and structural morphology of the phosphors were studied using X-ray diffractometer (XRD) and scanning electron microscope (SEM). The XRD spectra confirmed the crystallinity and formation of a pure ZnAl2O4 material which formed in single-phase cubic symmetry and Fd3m space group of ZnAl2O4. This crystal structure was maintained even after the substitution with Fe3+ ions, indicating a successful substitution of Fe3+ ions into the ZnAl2O4 structure. Energy dispersive spectroscopy was used for elemental composition investigations which confirmed the presence of Zn, Al, and O in pristine sample and also confirmed the presence of Zn, Al, O, and Fe in doped ZnAl2O4 samples. Diffuse reflectance spectra analysis was used for in-depth investigation of the effects of Fe3+ doping on the band gap of ZnAl2O4. Photoluminescence (PL) spectroscopy, excited using a xenon lamp, revealed two broad emission bands at approximately 470 nm and 730 nm. These emissions are attributed to the 4T1→6A1 and 4T2→6A1 transitions of Fe3+ ions, which occupy the tetrahedral (Tet) and the octahedral (Oct) coordination sites, respectively, within the ZnAl2O4 lattice. The CIE (Commission Internationale de I’Eclairage) confirmed that pure ZnAl2O4 color emission was lying in the blue region with color purity of 89% and CCT of 3384 K and upon doping with varying concentrations of Fe3+, the coordinates were tuned towards the white color region, indicating a potential for tunable white emission. Of particular interest is the 0.01 mol% Fe3+ doping which shifted the CIE coordinates to (0.33:0.31) with CCT of 5628K from (0.16:0.11) of the pristine ZnAl2O4. The vibrating Sample Magnetometer (VSM) studies revealed that the undoped ZnAl2O4 host material exhibits diamagnetic behavior, characterized by a weak repulsion to the magnetic field. In contrast, Fe-doped ZnAl2O4 displayed distinct magnetic properties and as varying Fe concentrations. These synthesized materials demonstrate great potential for various applications, such as light displays, magnetic refrigeration, catalysis, and light-emitting diodes (LEDs), due to their unique optical, luminescent, magnetic, and structural properties
Keywords
Luminescence, band gap, diamagnetic, color purity, color coordinate temperature
| Apply for student award at which level: | MSc |
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| Consent on use of personal information: Abstract Submission | Yes, I ACCEPT |
