Structural, optoelectronic and thermoelectric properties of Cs-based fluoroperovskites CsMF3 (M= Ge, Sn or Pb)

The structural and optoelectronic properties of Cs-based fluoroperovskites CsMF3 (M = Ge, Sn or Pb) were studied using the generalized gradient approximation of Perdew-burke-Ernzerhof (GGA-PBE) based on density functional theory (DFT) under the ABINIT code. The obtained lattice parameters are found to be in a good agreement with previous theoretical and experimental works. The studied electronic band structures reveal that the studied compounds exhibit a semiconducting nature with a direct band gap at R-point symmetries. The calculated optical properties confirm that CsGeF3 and CsSnF3 can be candidates as absorber in solar cell appli-cations. However, the case of perovskite CsPbF3 shows that this material is a promising candidate to absorb ultraviolet radiation. On the other hand, the thermoelectric transport properties such as Seebeck coefficient (S), the thermal conductivity (k/tau), electrical conductivity (sigma/tau), power factor (PF) and figure of merit (ZT) have been studied as a function of temperature (T) and as a function of chemical potential (mu) by using BoltzTraP code to resolve the Boltzmann transport equation.