Theoretical prediction of double perovskite Cs ₂ Ag _x Cu _1-x In _y Tb _1-y Cl ₆ for infrared detection

Abstract

Abstract Recently, double perovskite A 2 B(I)B′(III)X 6 has attracted a huge amount of interest due to its wide application in the field of light detection. However, the biggest limitation in the pursuit of further developments in this area is the narrow detection range and the low carrier mobility. It is well known that the effective mean to overcome the above shortcomings is changing the B site ions of A 2 B(I)B′(III)X 6 concentration for the double perovskite. In this study, we study the photoelectronic properties included atomic structure, electronic properties and optical properties of Cs 2 Ag x Cu 1-x In y Tb 1-y Cl 6 ( x = 0, 0.25, 0.5, 0.75, 1; y = 0, 0.25, 0.5, 0.75, 1) using first-principles methods. Besides, we systematically investigate carrier mobility of Cs 2 Ag 0.75 Cu 0.25 In 0.75 Tb 0.25 Cl 6 . The results demonstrate Cs 2 Ag 0.75 Cu 0.25 In 0.75 Tb 0.25 Cl 6 is the most excellent photoelectronic performance with the narrow band gap reduced of 0.56 eV, compared with Cs 2 AgInCl 6 , broadening the light detection range. Moreover, the hole mobility is increased from 0.001 to 2.81 cm 2 v −1 s −1 , which promotes the separation of photogenerated carriers and enhance the photoelectron conversion efficiency. Our works demonstrate that the modification of metal concentration will modulate the optoelectronic performance properties of double perovskites, which provides a theoretical basis for the other double perovskites in potential infrared detection application.