Synthesis and characterization of AgI-Ag2O-SeO2 glass-nanocomposites embedded with beta-AgI and Ag2SeO3 nanocrystals.
Glass-nanocomposites of compositions xAgI - (1 - x)(0.40Ag2O-0.60SeO2) for 0.15 < or = x < or = 0.30 were prepared by quenching the melt of the appropriate mixtures of the chemicals AgI, AgNO3 and SeO2. Differential scanning calorimetry (DSC) was employed to determine the glass transition and crystallization temperatures. The as-prepared samples were heat-treated above glass transition temperature to observe the growth of nanoparticles. X-ray diffraction (XRD), field emission scanning electron microscopy (FE-SEM) and transmission electron microscopy (TEM) were used to explore the microstructure of these samples. These studies revealed the presence of beta-AgI and Ag2SeO3 nanocrystals in both the as-prepared and heat-treated samples. The particle size was found to decrease with the increase of AgI content in both cases. The heat-treated samples showed increased tendency of crystallization for the compositions with higher AgI content. The beta-alpha phase transition of AgI crystals was observed at approximately 147-149 degrees C for heat-treated samples. Fourier transform infrared (FTIR) spectra revealed that the basic structure of the glassy network remained invariant to change of AgI content as well as to heat-treatment.
Department of Solid State Physics, Indian Association for the Cultivation of Science, Jadavpur, Kolkata 700032, India.
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Ghosh