Band Structure and Optical Spectra of Double Perovskite Cs2AgBiBr6 for Solar Cells Performance

The present study reports on the electronic band structure and optical properties of Cs2AgBiBr6 doubleperovskite material using a pseudopotential plane-wave method within the generalized gradient approximation. Our results show that Cs2AgBiBr6 has a good absorption in the visible spectrum region, nevertheless, it has an indirect band gap of magnitude of 1.32 eV. This limits its application in photovoltaics. An alternative is proposed to overcome this shortcoming.