Polycrystalline samples of Cs 1.17 In 0.81 Cl 3 were prepared by annealing a mixture of CsCl, InCl, and InCl 3 , stoichiometric for the targeted CsInCl 3 . Synchrotron powder X-ray diffraction refinement and chemical analysis by energy dispersive X-ray indicated that Cs 1.17 In 0.81 Cl 3 , a tetragonal distorted perovskite derivative (I4/m), is the thermodynamically stable product. The refined unit cell parameters and space group were confirmed by electron diffraction. In the tetragonal structure, In + and In 3+ are located in four different crystallographic sites, consistent with their corresponding bond lengths. In1, In2, and In3 are octahedrally coordinated, whereas In4 is at the center of a pentagonal bipyramid of Cl because of the noncooperative octahedral tilting of In4Cl 6 . The charged-ordered In + and In 3+ were also confirmed by X-ray absorption and Raman spectroscopy. Cs 1.17 In 0.81 Cl 3 is the first example of an inorganic halide double perovskite derivative with charged-ordered In + and In 3+ . Band structure and optical conductivity calculations were carried out with both generalized gradient approximation (GGA) and modified Becke-Johnson (mBJ) approach; the GGA calculations estimated the band gap and optical band gap to be 2.27 eV and 2.4 eV, respectively. The large and indirect band gap suggests that Cs 1.17 In 0.81 Cl 3 is not a good candidate for photovoltaic application.
All Science Journal Classification (ASJC) codes
- Materials Chemistry
- Chemical Engineering(all)