Study of thermodynamic, mechanical, photo-catalytic, optoelectronic and thermoelectric properties of ferromagnetic CoSc2(S/Se)4 spinels for energy conversion devices: DFT plus mBJ calculations

초록

With the increasing demand for materials that can perform more than one task and possess improved properties, the demand for systems that can be applied in optoelectronic and thermoelectric devices is also increasing. Spinel compounds, which are known for their ability to adapt to different structures and possess adjustable electronic and magnetic properties, have attracted much attention for further investigation. The physical properties, mechanical properties, optoelectronic properties, magnetic properties, and transport properties of the CoSc2(S/Se)(4) spinel compounds are systematically examined in this research study. The Fd (3) over barm space group causes these compounds to have cubic-shaped crystals. Negative formation energies show that the system is thermodynamically stable, and the Born stability criteria show that it is mechanically stable. The electronic band structures and density of states (DOS) show a direct band gap, which proves that they are semiconductors. The static dielectric constants for CoSc2S4 and CoSc2Se4 are 7.4 and 8.3, respectively. Optical absorption spectra show that both compositions absorb a lot of light from the IR to the visible range, with the strongest absorption in the visible range. Adding Co ions causes ferromagnetic ordering, which is shown by the presence of strong local magnetic moments. The thermoelectric properties are examined in a 300-800 K temperature range, revealing an enhancement in both electrical and thermal conductivities as the temperature increases. Also, both compounds have high Seebeck coefficients, which range from 239 & micro;V K-1 to 245 & micro;V K-1. For the studied materials, the figure of merit (ZT) remains consistent in the said temperature range. According to the results, the CoSc2(S/Se)4 spinels can be good candidates for use in optoelectronic and thermoelectric devices.

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