无机阳离子拟卤化物二维CsPb(SCN)Br钙钛矿单晶

Inorganic-Cation Pseudohalide 2D Cs Pb(SCN) Br Perovskite Single Crystal.

作者信息

Liao Chwen-Haw, Chen Chiung-Han, Bing Jueming, Bailey Christopher, Lin Yi-Ting, Pandit Twishi Mukul, Granados Laura, Zheng Jianghui, Tang Shi, Lin Bi-Hsuan, Yen Hung-Wei, McCamey Dane R, Kennedy Brendan J, Chueh Chu-Chen, Ho-Baillie Anita W Y

机构信息

School of Physics University of Sydney Nano Institute, The University of Sydney, Sydney, NSW, 2006, Australia.

Department of Chemical Engineering, National Taiwan University, Taipei, 106, Taiwan.

出版信息

Adv Mater. 2022 Feb;34(7):e2104782. doi: 10.1002/adma.202104782. Epub 2021 Dec 21.

DOI:10.1002/adma.202104782

PMID:34866252

Abstract

Most of the reported 2D Ruddlesden-Popper (RP) lead halide perovskites with the general formula of A B X (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, Cs Pb(SCN) Br , 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) Br 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 CsPbBr (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 Cs Pb(SCN) Br -single-crystal photodetector is demonstrated with respectable responsivity of 8.46 mA W and detectivity of ≈1.2 × 10 Jones at a low bias voltage of 0.5 V.

摘要

大多数报道的通式为AₙBₙ₊₁X₃ₙ₊₁（n = 1, 2, …）的二维Ruddlesden-Popper（RP）铅卤化物钙钛矿由A位取代的有机间隔层分隔的层状钙钛矿组成。迄今为止，仅报道了少量X位取代的RP钙钛矿。在此，报道了首例无机阳离子拟卤化物二维相钙钛矿单晶CsPb(SCN)₂Br₂。它是通过反溶剂气相辅助结晶（AVC）法在室温下合成的。它呈现出空间群为Pmmn（#59）所描述的标准单层（n = 1）Ruddlesden-Popper结构，且钙钛矿层之间的间距较小（d = 1.69 Å）。发现SCN阴离子将二维Pb(SCN)₂Br₂骨架轻微弯曲成风筝形八面体，限制了准二维钙钛矿结构（n > 1）的形成。这种二维单晶在450 K时表现出向三维CsPbBr₃（Pm3m #221）的可逆一级相变。它具有160 meV的低激子结合能——是二维钙钛矿（n = 1）中最低的之一。展示了一种CsPb(SCN)₂Br₂单晶光电探测器，在0.5 V的低偏置电压下具有8.46 mA W的可观响应度和约1.2×10¹² Jones的探测率。