paper Optoelectronic properties of Rb-doped inorganic double perovskite Cs2AgBiBr6

Based upon supercell models and electronic structure calculations, we studied the effects of Rb-dopant for substituting Ag and Cs in double perovskite Cs2AgBiBr6. The tolerance factors and octahedral factors suggest Rbdoped systems are stable. The dopant formation energies (-5.37 and -3.00 eV for subsituting Ag and Cs, respectively) indicate introducing Rb-dopant are exothermic. Rb-dopant changes the indirect band gap (2.25 eV) of pristine Cs2AgBiBr6 into direct band gap (2.27 and 2.19 eV for subsituting Ag and Cs, respectively) without introducing impurity states in band gap. It also amplifies optical absorptions, decreases (increases) electron (hole) effective masses, and enlarges elastic constant.

Automated summary

Introducing Rb-dopant in Cs2AgBiBr6 double perovskite stabilizes the material, changes its band gap properties, amplifies optical absorptions, and alters electron and hole effective masses.