First-Principles Study on Material Properties and Stability of Inorganic Halide Perovskite Solid Solutions CsPb(I${}_{1-x}$Br${}_x$)${}_3$ towards High Performance Perovskite Solar Cells

Abstract

All-inorganic halide perovskites have attracted a great interest as a promising light harvester of perovskite solar cells due to their enhanced chemical stability. In this work we investigate the material properties of solid solutions CsPb(I${}_{1-x}$Br${}_x$)${}_3$ in cubic phase by applying the virtual crystal approximation approach within a density functional theory framework. First we check the validity of constructed pseudopotentials of the virtual atoms (X = I${}_{1-x}$Br${}_x$) by verifying that the lattice constants follow the linear function of mixing ratio. We then suggest an idea of using the hybrid HSE functional with linear increasing value of exact exchange term as increasing the Br content x, which produces the band gaps of CsPbX3 in good agreement with the available experimental data. The calculated light absorption coefficients and reflectivity show the systematic varying tendency to the Br content. We calculate the phonon dispersions of CsPbX3, CsX and PbX2 as slightly changing their volumes, revealing the phase instability of CsPbX3 and calculating the thermodynamic potential function differences. By projecting Gibbs free energy differences onto the plane of G = 0, we determine the P - T diagram for CsPbX3 to be stable against the chemical decomposition, highlighting that the area of being stable extends gradually as the Br content increases.

References in corpus (9)

• Quantum ESPRESSO: a modular and open-source software project for quantum simulations of materials
• Restoring the density-gradient expansion for exchange in solids and surfaces
• Generalized gradient approximation for solids and their surfaces
• The GW compendium: A practical guide to theoretical photoemission spectroscopy
• Spontaneous Octahedral Tilting in the Cubic Inorganic Caesium Halide Perovskites CsSnX${}_3$ and CsPbX${}_3$ (X = F, Cl, Br, I)
• Kinetically Stable Single Crystals of Perovskite-Phase CsPbI${}_3$
• Influence of halide composition on the structural, electronic, and optical properties of mixed CH${}_3$NH${}_3$Pb(I${}_{1-x}$Br${}_x$)${}_3$ perovskites calculated using the virtual crystal approximation method
• First-principles study on the electronic and optical properties of inorganic perovskite Rb1-xCsxPbI3 for solar cell applications
• Revealing the stability and efficiency enhancement in mixed halide perovskites MAPb(I${}_{1-x}$Cl${}_x$)${}_3$ with ab initio calculations