Theoretical Study on Optical Absorption of Lead-Free Double Perovskites Cs2AgBiBr6 and Cs2InBiBr6.

We have studied the optical absorption of lead-free double perovskites Cs₂AgBiBr₆ and Cs₂InBiBr₆ using the solutions of the Dirac–Kohn–Sham equations. It is found that the absorption coefficient of Cs₂AgBiBr₆ in the high-energy part of the solar spectrum is considerably large and that the absorption spectrum of Cs₂InBiBr₆ shows strong similarity to that of CH₃NH₃PbI₃ in the main part of the solar spectrum. [ABSTRACT FROM AUTHOR]