Synthesis and Characterization of Zinc Oxide Nanoparticles

Abstract

The manufacture and characterisation of nanosized zinc oxide particles, as well as their use for UV shielding on cotton and wool textiles, are described. The nanoparticles were made under various temperature (90 or 150°C) and reaction media conditions (water or 1,2-ethanediol). To obtain tiny monodispersed particles, a high temperature was required. To evaluate the nanoparticles' composition, shape, size and crystallinity, researchers employed Fourier transformed infrared spectroscopy (FTIR), transmission electron microscopy (TEM) and X-ray powder diffractometry (XRD). The dried particles' specific surface area was also calculatedAfter that, ZnO nanoparticles were added to cotton and wool samples to provide them sunscreen activity. UV–V is spectrophotometry and the computation of the ultraviolet protection factor were used to evaluate the treatment's efficiency (UPF). Fabrics were subjected to physical testing (tensile strength and elongation) before and after being treated with ZnO nanoparticles.

The zinc oxide nanoparticles were made via precipitation, which involved pouring a surfactant solution (5 percent PEG) into a three-neck flask, then dropping zinc acetate and ammonium carbonate into the flask at the same time with rapid stirring. After the reaction, the suspension was stirred for 2 hours at ambient temperature, the precipitate was filtered multiple times with ammonia solution and 100% ethanol, dried under vacuum for 12 hours and then calcined in a 450°C oven for 3 hours. The nanoparticles of zinc oxide were then obtained.

Due to their considerable electrical and optical characteristics, which are very helpful in building nanoscaled optoelectronic and electronic devices with multifunctionality, there has been a rising need for the development of nanosized semiconductors in recent years. Zinc oxide (ZnO) is a unique electrical and photonic wurtzite n-type semiconductor with a broad direct band gap of 3.37 eV and a high exciton binding energy (60 meV) at ambient temperature among diverse semiconducting materials. Because of ZnO's high exciton binding energy, excitonic transitions might occur even at ambient temperature, potentially resulting in higher radiative recombination efficiency for spontaneous emission and a lower threshold voltage for laser emission. Because wurtzite lacks a centre of symmetry and has a significant electromechanical coupling, it has strong piezoelectric and pyroelectric characteristics, making it useful in mechanical actuators and piezoelectric sensors.

Due to its comparable qualities to GaN, ZnO is a possible contender for optoelectronic applications in the short wavelength range (green, blue, UV), information storage and sensors. Nanogenerators, gas sensors, biosensors, solar cells, varistors, photodetectors and photocatalysts are just a few of the uses for ZnO nanoparticles. Various approaches for the preparation of ZnO nanopowders have been developed, including sol-gel, microemulsion, thermal decomposition of organic precursors, spray pyrolysis, electrodeposition, ultrasonic, microwave-assisted techniques, chemical vapour deposition and hydrothermal and precipitation methods, according to the literature review. The majority of these procedures were not frequently employed on a broad scale, however chemical synthesis was widely used due to its ease of use and lower cost. The manufacture of ZnO nanoparticles via a chemical approach is described, as well as their characterisation using X-ray diffraction, scanning electron microscopy (SEM), transmission electron microscopy (TEM), selected area electron diffraction (SAED), UV-vis absorbance and photoluminescence spectra.