Aloevera–Assisted synthesis of Dy3+-doped zinc chromite nanoparticles: Structural, photoluminescence, and supercapacitor studies

Abstract

In this study, Dysprosium-doped Zinc chromite nanoparticles (NPs) were synthesized via Exothermic Combustion Synthesis using $Aloevera$ extract as a green fuel. The calcined samples (500 °C, 3 h) were thoroughly characterized. X-ray diffraction confirmed a pure cubic spinel structure with crystallite size decreasing from 14.42 nm to 11.18 nm as Dy content increased. Morphological analysis revealed randomly shaped nanoparticles and nanorods. The optical band gap narrowed from 3.12 eV to 3.03 eV. Photoluminescence spectra (${\lambda }_{ex}$ = 275 nm) exhibited a strong emission at 567 nm, with concentration quenching beyond 5 mol%. Chromaticity and correlated color temperature analyses verified yellowish-green emission from Dy${}^{3+}$ ions, suitable for indoor lighting. Electrochemical studies, including cyclic voltammetry, elucidated the redox behavior and electrode kinetics. The specific capacitance varied from 79.28 F/g to 114.34 F/g, depending on dopant concentration. These findings highlight Dy${}^{3+}$-doped ZnCr₂O₄ as a promising material for energy storage and display applications.