Pressure‐Induced Phase Transition, Jahn‐Teller Suppression, Optical and Electronic Property Evolutions in Ruddlesden‐Popper Perovskites Rb2CuCl4‐xBrx. Issue 21 (8th September 2021)

• Record Type: Journal Article
• Authors: Liu, Ke; Li, Chen; Wen, Ting; Jiang, Dequan; Jiang, Zimin; Ma, Yingying; Wang, Yonggang
• Is Part Of: Chemistry, an Asian journal. Volume 16:Issue 21(2021)
• Page Start: 3437
• Page End: 3443
• Publication Date: 2021-09-08
• Subjects: High pressure -- RP perovskite -- Halide -- Jahn-Teller distortion -- Piezochromism; Chemistry -- Periodicals; 540.5
• DOI: 10.1002/asia.202100859
• Languages: English
• ISSNs: 1861-4728

Abstract

Abstract: Transition‐metal containing halides with Ruddlesden‐Popper (RP) perovskite structures have received extensive attention owing to their emerging and anisotropic photoelectric functionalities. Among them, A 2 Cu X 4 ( A =alkali metal or organic cations, X =Cl, Br, I) series are particular, because of the Jahn‐Teller distortion of Cu 2+ sensitive to external stimuli such as temperature and pressure. In this article, we report the structure evolution and physical property responses of RP perovskites Rb2 CuCl4‐ x Br x ( x =1, 2) to external pressure. Dramatic structural phase transitions from orthorhombic to monoclinic occur around 3.0 GPa in both materials regardless of their distinct compositions. Structure analyses reveal the suppression and final vanishing of the Jahn‐Teller distortion of Cu 2+ cations under compression and crossing the phase transition, respectively. Rb2 CuCl4‐ x Br x perovskites exhibit abrupt bandgap narrowing (from reddish‐brown to black) along with the structural phase transition, and an overall bandgap narrowing of 75% up to ∼27 GPa but still keeping semiconductive. During the compression processes, the resistances of Rb2 CuCl4‐ x Br x have been greatly reduced by 5‐orders of magnitude. Moreover, all of the pressure‐induced phenomena in Rb2 CuCl4‐ x Br x perovskites are reversible upon decompression and no obvious difference is observed for the pressure responses between [CuCl4 Br2 ] and [CuCl4 (Cl, Br)2 ] coordination environments. The impact of pressure on the structural and physical properties in two‐dimensional Rb2 CuCl4‐ x Br x provides in‐depth understanding on the structure design of functional halide perovskites at ambient conditions. Abstract : Under pressure : The crystal structure, optical and electrical properties of all‐inorganic RP perovskites Rb2 CuCl2 Br2 and Rb2 CuCl3 Br under high pressure of up to 26.9 GPa are reported.