Abstract
Willemite is an inorganic semiconductor material used for optoelectronic applications. The present study purposes a new polymer thermal treatment method involving calcination temperature to fabricate the willemite nanoparticles. The effects of polyvinylpyrrolidone (PVP) on the structural and optical properties of the material were thoroughly investigated. Thermogravimetric and its derivative confirmed the decomposition behavior of PVP. The minimum calcination temperature to decompose PVP was appraised at 740 °C. The FTIR and the Raman analyses confirmed the presence of organic source before the calcination process and the formation of the crystalline structure of the willemite nanoparticles after the heat treatment. The optimum PVP concentration in this study based on the FTIR results was found to be 40 g L−1. This is the minimum concentration at which the willemite nanoparticles remained pure with homogenous distribution. X-ray diffraction analysis of the PVP samples before calcination was confirmed to be amorphous, and upon calcination between 800 and 1000 °C, an α-willemite phase was obtained. The morphology and the average particle size were determined with FESEM and HR-TEM analysis. The average particle size is between 23.8 and 36.7 nm. The optical energy band was found to be increasing from 5.24 to 5.32 eV with the corresponding increase in PVP concentration from 20 to 50 g L−1. The findings in this study provides a new pathway to understand the effects of PVP concentrations on the structural and optical properties of willemite semiconductor nanoparticles as it may have key potential applications for future optoelectronic devices.Graphical abstractThe primary task of polyvinylpyrrolidone (PVP) is to serve as a capping agent and to stabilize the metallic salts. The interaction between the PVP and the metallic salts (zinc acetate dihydrate and silicon tetraacetate) is through the strong ionic bonds between the metallic ions and the amide group via oxygen in the PVP chain. The PVP stabilizes the dissolved metallic precursor by amide group steric and electrostatic stabilization. In the drying process at the temperature about 80 °C, the PVP decompose to the shorter polymer chains which they cap the metallic ions. In the step of calcination at the range of 900 °C for 1–4 h, the polymer content and unwanted anions are entirely removed and the nucleation of willemite nanoparticles achieved.
Highlights
Polymers are currently attracting considerable research attention because of their broad industrial applications
The optimum PVP concentration in this study based on the FTIR results was found to be 40 g L-1
In accordance with XRD, FESEM and HR-TEM results, the crystallite size, and particles size of the willemite NPs decreased with increasing PVP concentration from 36.7 to 23.8 nm
Summary
Polymers are currently attracting considerable research attention because of their broad industrial applications. Conventional sol–gel and solid-state technique are often used methods for producing willemite NPs for phosphor application In this context, Rasdi et al [41] used the sol–gel technique to synthesize willemite nanophosphors at the calcination temperature of 1000 °C/ 2 h and obtained an average particle size of 181 nm. It was inferred that willemite NPs synthesized by hydrothermal routes mostly involves low calcination temperature ranging between 200 and 280 °C but lengthy heating period [44, 45]. A constant heating rate of 5 °C min-1 was used throughout the process for the decomposition of the organic components and crystallization of the material In this instance, the polymer (PVP) played the role of a capping agent that contributed a vital part to the formation of the willemite nanoparticle. The absorption properties were probed using the UV–vis spectrometer (Shimadzu model UV-3600, Kyoto, Japan) and photoluminescence (PL) (Perkin Elmer LS 55, Waltham, MA, USA) was used to analyze the optical properties of the materials at room temperatures, within the wavelength of 200–800 nm
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Free) 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
