Improving the phase stability of inorganic lead halide perovskites through K/Rb doping

Abstract

All-inorganic perovskites have gained considerable significance. Despite their superior thermal robustness, poor phase stability has rendered inorganic perovskites adverse. Herein, on the basis of first-principles calculations, we find that the incorporation of rubidium (Rb) and potassium (K) in an appropriate ratio will stabilize CsPbI2Br perovskites considerably, in which the cooperative interactions between Rb/K, I and Br play an important role. Besides, it is verified that 2D orthorhombic CsPbI3 with a thickness of ∼1 nm exhibits outstanding stability, even exceeding the non-perovskite, yellow structure and has a suitable band gap for solar cell applications.

Rubidium Doping to Enhance Carrier Transport in CsPbBr3 Single Crystals for High-Performance X-Ray Detection

“…It should be pointed out that our experimental observation about the Rb-doping effect is similar to that observed in organic–inorganic hybrid perovskites CH 3 NH 3 Sn 0.65 Pb 0.35 I 3 , where Rb doping was also found to increase the atomic interaction between Sn/Pb and I . Consequently, the stronger orbital coupling between Pb and Br atoms changes the band dispersion or band edge structure, which in turn influences the effective mass of electron and holes, and results in an enhancement of carrier transport and X-ray detection performance as observed in this work. It should be mentioned that the obtained XRD patterns did not show significant changes in terms of peak intensity and peak width, except an obvious shift of XRD peaks toward a higher 2θ angle with increasing Rb-doping ratio, suggesting that the crystallinity difference is very small for these three samples.…”

“…The Rb doping has been demonstrated as an effective approach to improve phase stability , and device performance − in perovskite solar cells based on organic–inorganic hybrid perovskites due to the enhanced orbital interaction between Pb and I . It is thus anticipated that Rb doping may also play a positive role in all-inorganic perovskite CsPbBr 3 direct conversion X-ray detectors.…”

CsPbI3 nanocrystal films: towards higher stability and efficiency

“…Both experimental and theoretical works have reported the incorporation of alkali metal ions to improve the phase stability and device performance of perovskites. [54][55][56][57] After incorporating Rb/K dopants, an effective improvement of moisture-resistance of the films was observed, attributed to the formation of a water-repelling surface. This was also confirmed by theoretical calculation with a mitigated charge shift, alleviated lattice distortion and a higher activation barrier in Cs 0.92 Rb 0.08 PbI 3 /Cs 0.92 Rb 0.08 PbI 3 .…”