Inorganic-Cation Pseudohalide 2D Cs2Pb(SCN)2Br2 Perovskite Single Crystal
Journal
Advanced Materials
Journal Volume
34
Journal Issue
7
Date Issued
2022
Author(s)
Liao C.-H
Chen C.-H
Bing J
Bailey C
Lin Y.-T
Pandit T.M
Granados L
Zheng J
Tang S
Lin B.-H
McCamey D.R
Kennedy B.J
Chueh C.-C
Abstract
Most of the reported 2D Ruddlesden–Popper (RP) lead halide perovskites with the general formula of An+1BnX3n+1 (n = 1, 2, …) comprise layered perovskites separated by A-site-substituted organic spacers. To date, only a small number of X-site-substituted RP perovskites have been reported. Herein, the first inorganic-cation pseudohalide 2D phase perovskite single crystal, Cs2Pb(SCN)2Br2, is reported. It is synthesized by the antisolvent vapor-assisted crystallization (AVC) method at room temperature. It exhibits a standard single-layer (n = 1) Ruddlesden–Popper structure described in space group of Pmmn (#59) and has a small separation (d = 1.69 Å) between the perovskite layers. The SCN− anions are found to bend the 2D Pb(SCN)2Br2 framework slightly into a kite-shaped octahedron, limiting the formation of a quasi-2D perovskite structure (n > 1). This 2D single crystal exhibits a reversible first-order phase transformation to 3D CsPbBr3 (Pm3m #221) at 450 K. It has a low exciton binding energy of 160 meV—one of the lowest for 2D perovskites (n = 1). A Cs2Pb(SCN)2Br2-single-crystal photodetector is demonstrated with respectable responsivity of 8.46 mA W−1 and detectivity of ≈1.2 × 1010 Jones at a low bias voltage of 0.5 V. © 2021 The Authors. Advanced Materials published by Wiley-VCH GmbH
Subjects
inorganic 2D perovskites; low exciton binding energy; photodetectors; photoresponse; pseudohalide; reversible phase transformation; single crystals
SDGs
Other Subjects
Binding energy; Excitons; Lead compounds; Perovskite; Phase transitions; Photodetectors; Positive ions; Single crystals; Advanced materials; Exciton-binding energy; Inorganic 2d perovskite; Inorganic cations; Inorganics; Low exciton binding energy; Photoresponses; Pseudo Halide; Reversible phase transformations; Ruddlesden-Popper; Photons
Type
journal article