Growth, impedance analysis, and dielectric relaxation of all-inorganic lead-free cesium bismuth chloride (Cs3Bi2Cl9) single crystal for energy storage application

This article delves into the growth, impedance analysis, and dielectric relaxation of all-inorganic lead-free cesium bismuth chloride (Cs3Bi2Cl9) single crystals, highlighting their potential for energy storage applications. The study employs various characterization techniques, including optical microscopy, field-emission scanning electron microscopy (FE-SEM), energy-dispersive X-ray spectroscopy (EDX), X-ray diffraction (XRD), Fourier Transform Infrared (FTIR), and Raman spectroscopy, to investigate the crystal's morphology, lattice structure, and chemical bonds. The optical properties of the single crystal are explored using UV–visible and photoluminescence spectroscopy, revealing both direct and indirect bandgaps. The temperature-dependent I–V measurement and dielectric response are analyzed using an electrochemical workstation, providing insights into the crystal's charge-transport properties. The study also employs computational methodologies, such as the Vienna Ab-initio Simulation Package (VASP), to understand the electronic structure and band structure of the crystal. The results indicate that the Cs3Bi2Cl9 single crystal exhibits a high dielectric constant, negative temperature coefficient of resistance (NTCR) behavior, and Debye-type relaxation. The article concludes by discussing the potential applications of Cs3Bi2Cl9 single crystals in optoelectronics and energy storage, emphasizing their superior stability and unique properties.