Solvent-free synthesis and poole-frenkel conduction in FeS2 nanoflakes

초록

In this study, we report a successful solvent-free synthesis of FeS2 nanoflakes, that is a scalable alternative to conventional solvothermal methods. We investigate their detailed structural and charge carrier transport properties. Successful synthesis is confirmed via x-rays diffraction (XRD), and it is revealed that FeS2 has a cubic crystal structure, and the average crystallite size was determined to be similar to 25 nm. We confirmed the exclusion of marcasite phase and oxides impurities by correlating Raman and FTIR spectroscopy. Scanning Electron Microscopy (SEM) reveals a distinct flake-like morphology. Moreover, beyond structural integrity current-voltage (I-V) measurements conducted within the temperature range of 300 K to 400 K demonstrate nonlinear behavior confirming semiconducting nature consistent with recent literature. Further analysis indicates that the conduction mechanism follows the Poole-Frenkel model which involves field-assisted thermal excitation of trapped charge carriers into conduction band. The Arrhenius plot derived from the data yields an activation energy of 0.17 eV, providing new insights into the electronic properties of FeS2 and its potential for advanced technological applications such as lithium-ion batteries and solar cells. The dielectric properties of FeS2 were also studied in the frequency range of 20 Hz to 1 MHz, which illustrates a high dissipation at low frequencies. Using impedance spectroscopic data, we were also able to observe the overlapped large polaron hopping (OLPH) conduction mechanism in our material. This study provides a comprehensive framework linking sustainable fabrication with a vital understanding of carrier dynamics in metal chalcogenide nanostructures.

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