Temperature Control of Yellow Photoluminescence from SiO2-Coated ZnO Nanocrystals

• Published in: Nanomaterials (Basel, Switzerland) Vol. 12; no. 19; p. 3368
• Main Authors: Kumar, Narender, Poulose, Vijo, Laz, Youssef Taiser, Chandra, Falguni, Abubakar, Salma, Abdelhamid, Abdalla S., Alzamly, Ahmed, Saleh, Na’il
• Format: Journal Article
• Language: English
• Published: Basel MDPI AG 27.09.2022; MDPI
• Subjects: Chemical precipitation; Crystals; Diodes; Emission measurements; Emission spectra; Ethanol; Excitons; Fourier transforms; Infrared analysis; Light; Light scattering; Luminescence; Microscopy; Nanocomposites; Nanocrystals; Nanomaterials; Nanoparticles; Nanotechnology; nonradiative relaxation; Photocatalysis; Photoluminescence; Photon correlation spectroscopy; Photons; Radiative recombination; Recombination; Research methodology; Scattering; Silica; Silicon dioxide; Software; Spectrum analysis; Surface defects; Temperature control; Temperature effects; time-resolved photoluminescence; X ray powder diffraction; X-ray diffraction; X-ray spectroscopy; Zinc oxide; Zinc oxides; ZnO nanocrystals; United Kingdom > UK; United States > US; Japan
• ISSN: 2079-4991; 2079-4991
• DOI: 10.3390/nano12193368

In this study, we aimed to elucidate the effects of temperature on the photoluminescence from ZnO–SiO2 nanocomposite and to describe the preparation of SiO2-coated ZnO nanocrystals using a chemical precipitation method, as confirmed by Fourier transform infrared (FTIR) and powder X-ray diffraction analysis (XRD) techniques. Analyses using high-resolution transmission microscopy (TEM), energy-dispersive X-ray spectroscopy (EDX), dynamic light scattering (DLS), and electrophoretic light scattering (ELS) techniques showed that the new nanocomposite has an average size of 70 nm and 90% silica. Diffuse reflectance spectroscopy (DRS), photoluminescence (PL), and photoluminescence-excitation (PLE) measurements at different temperatures revealed two emission bands at 385 and 590 nm when the nanomaterials were excited at 325 nm. The UV and yellow emission bands were attributed to the radiative recombination and surface defects. The variable-temperature, time-resolved photoluminescence (VT-TRPL) measurements in the presence of SiO2 revealed the increase in the exciton lifetime values and the interplay of the thermally induced nonradiative recombination transfer of the excited-state population of the yellow emission via deep centers (DC). The results pave the way for more applications in photocatalysis and biomedical technology.