Optoelectronic properties of Rb-doped inorganic double perovskite Cs2AgBiBr6.

[Display omitted] • Rb-doped double perovskites meet the requirements of perovskite structural stability. • Introducing Rb dopant into double perovskite Cs 2 AgBiBr 6 is exothermic. • Rb dopant cause direct band gap, and there are no the impurity states in band gap. • Rb dopant enhances the light absorption in the visible and infrared regions. • Rb dopant causes an increase (decrease) in the carrier mobility of electron (hole) Based upon supercell models and electronic structure calculations, we studied the effects of Rb-dopant for substituting Ag and Cs in double perovskite Cs 2 AgBiBr 6. The tolerance factors and octahedral factors suggest Rb-doped 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 Cs 2 AgBiBr 6 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. [ABSTRACT FROM AUTHOR]