Synthesis and characterization of low cost willemite based glass–ceramic for opto-electronic applications

Abstract

This paper presents a comprehensive study on thermal, structural and optical properties of novel willemite glass-ceramics. The precursor glass in the ZnO-SLS glass system was successfully prepared using conventional meltquenching technique and willemite (Zn 2 SiO 4 ) glass-ceramics were derived from this precursor glass by a control crystallization process. The effect of heat-treatment temperature on the phase transformation, morphology and size of Zn 2 SiO 4 crystal phase was examined using X-ray diffraction (XRD), field-emission scanning electron microscopy (FESEM) techniques. Furthermore, fourier transform infrared reflection (FTIR) spectroscopy was used to evaluate the Zn 2 SiO 4 crystal structural evolution. The average size of Zn 2 SiO 4 crystallite obtained from calculation of XRD is found to be in the range 30-60 nm, whereas the grain size observed in FESEM is in range of 200-400 nm. The appearance of SiO 2 , ZnO 4 and Zn-O-Si bands detected from FTIR indicate the formation of Zn 2 SiO 4 crystal phase. Besides, the study of the optical band gap has found that optical band gap of the glass-ceramics decreased as the heat treatment temperature increased. The photoluminescence spectra of willemite glass-ceramics exhibit two different emissions around 525 nm (green) and 585 nm (yellow); exhibit a characteristic of broad absorption band around 260 nm. These two different spectra reveal that the luminescence performance of the willemite glass-ceramics was enhanced with the progression of heat treatment temperature due to different located energy levels of the b-Zn 2 SiO 4 and a-Zn 2 SiO 4 crystalline phase. Such luminescent glass-ceramics was expected to find potential applications in phosphors and opto-electronic devices.

Polymer Thermal Treatment Production of Cerium Doped Willemite Nanoparticles: An Analysis of Structure, Energy Band Gap and Luminescence Properties

“…It is fascinating to note that SiO 2 shows an amorphous characteristics at calcination temperature less than 700 °C [ 41 ]. According to Zaid et al [ 23 ], the crystallization formation of SiO 2 phase in ZnO–SiO 2 system could not be achieved at a temperature below 700 °C due to its amorphous state, and this conforms with the findings of Omar et al [ 28 ]. In a similar context, Babu et al [ 48 ] reported that at greater calcination temperatures beyond 700 °C, the ZnO atoms are the main diffusing component in ZnO/SiO 2 composite.…”

“…Willemite has several prospective applications such as photonic devices [ 17 , 18 ], adsorbents [ 19 , 20 ], and laser crystal systems [ 21 , 22 ]. Willemite is also serving as a host material for guest ions like transitional metals or rare earth metals due to its ability to display a wide range of multicolors for luminescence devices [ 11 , 23 , 24 , 25 , 26 , 27 , 28 ]. For instance, the luminescence properties of rare earth ions (RE 3+ ) such as the longer emission lifetime, sharper luminescence array, and the characteristic spectral features (owed to their filled 4f shells and spared by the exterior 5s 2 and 5p 6 orbitals) are some of the exciting factors for choosing them in modern day optoelectronic applications.…”

A Study on Optical Properties of Zinc Silicate Glass-Ceramics as a Host for Green Phosphor

“…Zinc silicate (Zn 2 SiO 4 ) or willemite is well known among researchers as a supreme and most suitable host matrix for glass phosphor and other optoelectronic materials, since it has a quite huge band gap around 5.5 eV, high chemical compound stability, and a great glass transparency [7]. Besides, it also has another special feature-a large excitation binding energy-allowing it to be used as an enhancer for triggering the luminescence inside the neon discharged lamps, fluorescent lamps, black-and-white televisions, colour televisions, oscilloscopes, laser technology, optical communications, optical fibre amplifiers, waveguides, and light emitting diodes (LED) [8][9][10]. Nowadays, the production of low-cost zinc silicate glass and glass-ceramics is a topic of interest among researchers.…”

Effects of Calcination Holding Time on Properties of Wide Band Gap Willemite Semiconductor Nanoparticles by the Polymer Thermal Treatment Method

“…This is including the conventional sol–gel technique [16,17,18] and solid state method [19,20,21,22]. In addition, other researchers reported the production of willemite by hydrothermal method [23,24], co–precipitation method [25], sonochemical method [26], spray drying method [27], spray pyrolysis method [28,29], super critical water methods [30,31] and solvothermal method [32].…”