Penta‐PdPSe: A New 2D Pentagonal Material with Highly In‐Plane Optical, Electronic, and Optoelectronic Anisotropy

• Published in: Advanced materials (Weinheim) 2021-09, Vol.33 (35), p.e2102541-n/a
• Main Authors: Li, Peiyang, Zhang, Jiantian, Zhu, Chao, Shen, Wanfu, Hu, Chunguang, Fu, Wei, Yan, Luo, Zhou, Liujiang, Zheng, Lu, Lei, Hongxiang, Liu, Zheng, Zhao, Weina, Gao, Pingqi, Yu, Peng, Yang, Guowei
• Format: Article
• Language: English
• Subjects: 2D pentagonal materials; Anisotropy; Electron mobility; in‐plane anisotropy; Materials science; Optical properties; Optoelectronics; phototransistor; Polyelectrolytes; Symmetry; Two dimensional materials
• ISSN: 0935-9648; 1521-4095
• DOI: 10.1002/adma.202102541

Due to their low‐symmetry lattice characteristics and intrinsic in‐plane anisotropy, 2D pentagonal materials, a new class of 2D materials composed entirely of pentagonal atomic rings, are attracting increasing research attention. However, the existence of these 2D materials has not been proven experimentally until the recent discovery of PdSe2. Herein, penta‐PdPSe, a new 2D pentagonal material with a novel low‐symmetry puckered pentagonal structure, is introduced to the 2D family. Interestingly, a peculiar polyanion of [SePPSe]4− is discovered in this material, which is the biggest polyanion in 2D materials yet discovered. Strong intrinsic in‐plane anisotropic behavior endows penta‐PdPSe with highly anisotropic optical, electronic, and optoelectronic properties. Impressively, few‐layer penta‐PdPSe‐based phototransistor not only achieves excellent electronic performances, a moderate electron mobility of 21.37 cm2 V−1 s−1 and a high on/off ratio of up to 108, but it also has a high photoresponsivity of ≈5.07 × 103 A W−1 at 635 nm, which is ascribed to the photogating effect. More importantly, penta‐PdPSe also exhibits a large anisotropic conductance (σmax/σmax = 3.85) and responsivity (Rmax/Rmin = 6.17 at 808 nm), superior to most 2D anisotropic materials. These findings make penta‐PdPSe an ideal material for the design of next‐generation anisotropic devices. A new 2D pentagonal material, penta‐PdPSe, with low‐symmetry lattice characteristics, is introduced to the 2D family. Such a low‐symmetry structure endows this material with strong in‐plane anisotropy, in which high conductance and photoresponsivity anisotropic ratios of 4.74 and 6.17 are achieved, respectively. These results make 2D penta‐PdPSe an ideal material for the design of next‐generation anisotropic devices.