Optoelectronic investigations of needle-shaped Zn1-xSnxO nanoparticles synthesized by coprecipitation method

Abstract

In this work, Zn1-xSnxO (x = 0, 0.01, 0.02, 0.04, 0.06 and 0.1) nanoparticles were synthesized via the coprecipitation method. The prepared nanoparticles were characterized by x-ray powder diffraction (XRD), transmission electron microscope (TEM) and Fourier transform infrared spectroscopy (FTIR). The optical investigations were utilized by UV–vis spectroscopy (UV) and photoluminescence (PL). Moreover, the electrical studies were performed through dc conductivity and dielectric measurements. The successful Sn doping in ZnO nanoparticles induced structural and electronic modifications that triggered oriented growth and gave rise to smaller nanoparticles accompanied by lower lattice distortions and strains. Sn doping had a high impact on the morphology of ZnO nanoparticles, which transformed from nearly non-specified and circular to needle-like shape. Widening of the optical band gap was observed (2.6104 eV for x = 0.00 and 3.0760 eV for x = 0.02) escorted by a decrease in the lattice disorders, as the Urbach energy was reduced (2.8445 eV for x = 0.00 and 0.9980 eV for x = 0.02). Luminescent recombination mechanisms were detected from the UV to the blue region upon excitation by 330 nm. The UV emissions were suppressed whereas the blue emissions were improved due to Sn doping, rendering the prepared nanoparticles beneficial for biological fluorescence labeling applications. The concentration of x = 0.04 showed the minimum UV emissions as well as the minimum blue emissions. Furthermore, the dc conductivity (σdc) was enhanced by Sn doping, with x = 0.04 attaining the highest value of 0.3712 Ω−1.m−1 in comparison with 0.0002 Ω−1.m−1 for x = 0.00, at 573 K. The activation energy was found to increase in the low temperature region, while it decreases in the high temperature region. The dielectric parameters were enhanced by Sn doping, which introduces surface defects and charge carriers that aid in overcoming the sintering consequences and enhancing the dielectric response.