Effectively tuning the band gap of double perovskite Cs2Ag(BxBi1-x)Br6 (B = Sb3+, In3+) thin films.

[Display omitted] • Sb3+/In3+ doped Cs 2 AgBiBr 6 double perovskite thin films were prepared by spin coating method. • 70% In3+ and 100% Sb3+ can be doped into Cs 2 AgBiBr 6 thin films when annealed at 150 °C. • The band gap of Cs 2 Ag(In x Bi 1-x)Br 6 thin films increases from 2.55 eV to 2.64 eV as x increases from 0 to 0.7. • The band gap of Cs 2 Ag(Sb x Bi 1-x)Br 6 decreases from 2.55 eV to 2.25 eV as x increases from 0 to 1.0. Halide double perovskite Cs 2 AgBiBr 6 hinders its wide range of optoelectronic applications due to large band gap. This work focuses on Sb3+/In3+ doping to tune the band gap of Cs 2 AgBiBr 6 thin films. The influences of annealing temperature and doping amount of Cs 2 Ag(B x Bi 1-x)Br 6 (B = Sb3+, In3+) thin films were investigated. When annealed at the optimized temperature of 150 °C, the Cs 2 Ag(B x Bi 1-x)Br 6 (B = Sb3+, In3+) thin films accommodate up to 100% Sb3+ and 70% In3+, respectively, without showing any secondary phases. The band gap of Cs 2 Ag(B x Bi 1-x)Br 6 (B = Sb3+, In3+) thin films decreases as the increase of Sb3+ and increases as the increase of In3+ amount. Therefore, the band gap regulation of 0.39 eV is realized, with the smallest value of 2.25 eV for Cs 2 AgSbBr 6 and highest value of 2.64 eV for Cs 2 Ag 0.3 In 0.7 Br 6 , respectively. Our work confirms an approach to realize band gap adjustment of Cs 2 AgBiBr 6 thin films. [ABSTRACT FROM AUTHOR]