Experimental and Theoretical Investigation of the Structural and Opto-electronic Properties of Fe-Doped Lead-Free Cs2 AgBiCl6 Double Perovskite

Sachin Thawarkar; Sachin R Rondiya; Nelson Y Dzade; Nageshwar Khupse; Sandesh Jadkar

doi:10.1002/chem.202004902

Experimental and Theoretical Investigation of the Structural and Opto-electronic Properties of Fe-Doped Lead-Free Cs₂ AgBiCl₆ Double Perovskite

Chemistry. 2021 May 6;27(26):7408-7417. doi: 10.1002/chem.202004902. Epub 2021 Mar 22.

Authors

Sachin Thawarkar¹, Sachin R Rondiya², Nelson Y Dzade², Nageshwar Khupse³, Sandesh Jadkar¹

Affiliations

¹ Department of Physics, Savitribai Phule Pune University, Pune, 411007, India.
² School of Chemistry, Cardiff University, Cardiff, CF10 3AT, Wales, United Kingdom.
³ Centre for Materials for Electronic Technology, Dr. Homi Bhabha Road, Pune, 411008, India.

Abstract

Lead-free double perovskites have emerged as stable and non-toxic alternatives to Pb-halide perovskites. Herein, the synthesis of Fe-doped Cs₂ AgBiCl₆ lead-free double perovskites are reported that display blue emission using an antisolvent method. The crystal structure, morphology, optical properties, band structure, and stability of the Fe-doped double perovskites were investigated systematically. Formation of the Fe-doped Cs₂ AgBiCl₆ double perovskite is confirmed by X-ray diffraction (XRD) and X-ray photoelectron spectroscopy (XPS) analysis. XRD and thermo-gravimetric analysis (TGA) shows that the Cs₂ AgBiCl₆ double perovskite has high structural and thermal stability, respectively. Field emission scanning electron microscopy (FE-SEM) analysis revealed the formation of dipyramidal shape Cs₂ AgBiCl₆ crystals. Furthermore, energy-dispersive X-ray spectroscopy (EDS) mapping shows the overlapping of Cs, Bi, Ag, Fe, and Cl elements and homogenous incorporation of Fe in Cs₂ AgBiCl₆ double perovskite. The Fe-doped Cs₂ AgBiCl₆ double perovskite shows a strong absorption at 380 nm. It extends up to 700 nm, suggesting that sub-band gap states transition may originate from the surface defect of the doped perovskite material. The radiative kinetics of the crystals was studied using the time-correlated single-photon counting (TCSPC) technique. Lattice parameters and band gap value of the Fe-doped Cs₂ AgBiCl₆ double perovskites predicted by the density functional theory (DFT) calculations are confirmed by XRD and UV/Visible spectroscopy analysis. Time-dependent photo-response characteristics of the Fe-doped Cs₂ AgBiCl₆ double perovskite show fast response and recovery time of charge carriers. We believe that the successful incorporation of Fe in lead-free, environmentally friendly Cs₂ AgBiCl₆ double perovskite can open a new class of doped double perovskites with significant potential optoelectronics devices fabrication and photocatalytic applications.

Keywords: band gaps; density functional calculations; iron; perovskites; photoconductivity.

Abstract

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