A facile one-step microwave-assisted synthesis of bismuth oxytelluride nanosheets for optoelectronic and dielectric application: An experimental & computational approach

In the recent developments of research on various 2D materials, a new type of semiconducting material, bismuth oxychalcogenides (Bi2O2X, X = S, Se, Te), has gained tremendous attention among the scientific community. Compared to other Bi2O2X, Bi2O2Te has not acquired significant attention due to the difficulty of synthesizing stable composition. Here in this report, we have used "microwave-assisted synthesis method" to prepare bismuth oxytelluride samples with varying synthesis conditions. A few sharp and well-defined diffraction peaks were observed from crystallographic studies, along with several binary phases. Nanosheet-like morphology was observed for different as-prepared samples. The elemental mapping confirms the presence of Bi, O, and Te in the synthesized samples. In the UV-Vis absorption spectra, a redshift with the variation of synthesis conditions was observed, suggesting the presence of more acceptor states. The calculated bandgap energies display the wide bandgap nature of the samples. A broad photoluminescence emission spectrum with peaks centered around orange-red regions was observed for individual nanosheet cases, making them useful for various optoelectronic applications. The temperature and frequency-dependent dielectric measurements were carried out for the possible application in energy storage. The obtained conductivity of the samples is suitable for different electrical applications. The computational analysis using the DFT method was carried out to provide some necessary information about the structure and physical properties of the prepared materials.