A Comparative Study of Inorganic Lead Halide Perovskites By Analyzing The Electrical, Optical and Mechanical Properties

Due to higher structural stability in moist and airy environments, inorganic perovskite materials are now used in solar cells and optoelectronic devices, rather than organic ones. In this paper, three inorganic lead halide perovskites were simulated with varying halide anions. The common cations are Cesuim (Cs), Lead (Pb) and the anions are halogens (Cl, Br, and I). The resulting CsPbCl <inf xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">3</inf> , CsPbBr <inf xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">3</inf> , and CsPbI <inf xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">3</inf> materials were then investigated for their electrical, optical, and mechanical characteristics by using the first-principle DFT calculations. The energy gaps of these materials were identified utilizing the Materials Studio simulation system. The direct band gaps of CsPbCl <inf xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">3</inf> , CsPbBr <inf xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">3</inf> , and CsPbI <inf xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">3</inf> are 2.136 eV, 1.721 eV, and 1.535 e V, respectively. The work indicates that as the anion's size increases, the bandgap shrinks. For CsPbCl <inf xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">3</inf> , CsPbBr <inf xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">3</inf> , and CsPbI <inf xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">3</inf> , the corresponding lattice constants are 5.563 [A], 5.774 [A] and 6.123 [A]. These materials' conductance and susceptance were also discovered, which provides useful data about their conducting behavior. These materials' excellent light absorption capacity has been demonstrated by their optical characteristics, which involve their dielectric function, absorption function, loss function, and reflectivity. The most significant dielectric function peak appears for CsPbI <inf xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">3</inf> , while the highest conductivity and absorption peak is exhibited by CsPbCl <inf xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">3</inf> . Lastly, applying the Voigt approach, it can be observed from Poisson's ratio and Pugh's ratios that CsPbCl <inf xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">3</inf> displays the most optimal flexibility of the three structures in terms of mechanical characteristics.