Investigation of electronic, optoelectronic, and mechanical properties of lead-free cubic perovskite compound using density functional theory

This study depicts the physical characteristics, including electronic, structural, mechanical, magnetic, and optical properties, of the lead-free, inorganic, non-toxic cubic perovskite compound FrCdX3 (where X = Br, Cl, and F). The main goal is to evolve a lead-free, inorganic, non-toxic perovskite alternative along with suitable opto-electrical characteristics using density functional theory under generalized gradient approximation and the Perdew–Burke–Ernzerhof functional within the Cambridge Serial Total Energy Package program. The structural output describes compounds with smaller lattices and smaller cell volumes, which denotes stronger bonds between atoms. Electronic outcomes visualize that FrCdF3, FrCdCl3, and FrCdBr3 have a bandgap value of 3.109, 1.675, and 0.628 eV, respectively, which indicates an inverse relation between crystal structure size and bandgap. As a result, conductivity is increasing with increasing crystal size. This bandgap depicts them as good alternatives in solar cells, semiconductors, photodetectors, and light-emitting diodes. The optical findings describe their use in sensors, energy efficiency coating, and conductive films. The mechanical output demonstrates mechanical stability as all the compounds of FrCdX3 satisfy the Born stability law. Mechanical results illustrate that all the materials are ductile because Poisson’s ratio quantities are within the 0.26 to 0.32 range, and Pugh’s ratio quantities are above 1.75. In essence, increasing the structure size decreases the stiffness but increases the ductility. In the end, all the compounds of FrCdX3 show a diamagnetic nature as upward and downward spin fully superimposed on each other, which makes them a good fit for MRI machines, superconductors, and magnetic sensors.