Impact of fuel and reducing agent on photoluminescence and supercapacitor applications of rhombohedral silver gallium oxide (AgGaO2) nanoparticles

Abstract

To investigate the benefits of a green-mediated route compared to the chemical route in synthesising AgGaO2 NPs, both methods were employed, and a comprehensive analysis of their characterization, photoluminescence, and electrochemical properties was conducted. In this study, silver gallium oxide (AgGaO2) nanoparticles (NPs) were synthesised using two distinct methods: a chemical route employing urea as a fuel (AgGaO2U) and a green-mediated route using Aloevera gel extract as a reducing agent (AgGaO2A), followed by calcination at 600oC for 3 h. The XRD analysis confirmed the formation of a trigonal structure in both AgGaO2U and AgGaO2A NPs. Rietveld analysis provided insight into lattice parameters, space groups, and packing diagrams. AgGaO2A exhibited smaller NPs compared to AgGaO2U. The direct energy band gap, determined using Wood and Tauc’s relation, was 3.2 eV for AgGaO2U and 3.04 eV for AgGaO2A. AgGaO2A displayed a smaller crystallite size and a higher energy band gap. Photoluminescence spectra, excited at 224 nm, revealed emissions in the violet, blue, green, and red regions, with the highest intensity observed in the blue region. This was further confirmed by CIE coordinates, which fell within the blue region, with AgGaO2A exhibiting higher intensity than AgGaO2U. Electrochemical studies demonstrated supercapacitance values ranging from 24.8 to 69.8 F/g at different scan rates. While the choice of fuel or reducing agent influenced photoluminescence intensity, electrochemical studies showed consistent behaviour in both synthesised samples, suggesting their potential applications in displays and supercapacitors.