Direct Observation of the Linear Dichroism Transition in Two-Dimensional Palladium Diselenide

The linear dichroism (LD) transition within anisotropic photonic materials displays promising prospects for applications in polarization-wavelength-selective detectors, optical switching, and optical communication. In conventional two-dimensional (2D) anisotropic materials, the LD is predominantly u...

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Bibliographic Details
Published in:	Nano letters Vol. 20; no. 2; pp. 1172 - 1182
Main Authors:	Yu, Juan, Kuang, Xiaofei, Gao, Yuanji, Wang, Yunpeng, Chen, Keqiu, Ding, Zhongke, Liu, Jia, Cong, Chunxiao, He, Jun, Liu, Zongwen, Liu, Yanping
Format:	Journal Article
Language:	English
Published:	United States American Chemical Society 12-02-2020
Subjects:	palladium diselenide Two-dimensional material linear dichroism transition anisotropy
Online Access:	Get full text
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Summary:	The linear dichroism (LD) transition within anisotropic photonic materials displays promising prospects for applications in polarization-wavelength-selective detectors, optical switching, and optical communication. In conventional two-dimensional (2D) anisotropic materials, the LD is predominantly uniaxial over a broad spectrum of wavelengths and arises principally from the reduced symmetry of the materials. However, the LD transition behavior in crystalline 2D materials remains elusive. Here, we demonstrate the observation of a unique LD conversion phenomenon at a wavelength of 472 nm in palladium diselenide (PdSe2) using polarization-resolved absorption spectroscopy. This material exhibits prominent anisotropic responses and a high absorption ratio of α y /α x ≈ 1.11 at 364 nm, 1.15 at 532 nm, and 0.84 at 633 nm. We propose that this abnormal LD conversion behavior originates from the forceful localization rules at different parallel energy bands that exist within this material. Furthermore, the robust periodicity of Ag and B1g modes in polarization-resolved Raman spectroscopy is in good agreement with the theoretical structure symmetry analysis. This indicates the strong intrinsic LD effect in the anisotropic nature of PdSe2, which offers a macrolevel determination of crystal orientations. Such unique LD conversion features, in combination with strong LD effects, enable the air-stable PdSe2 to be a potential candidate for technological innovations in multispectral imaging, sensing, and polarization-sensitive and wavelength-controllable photoelectronic applications.
Bibliography:	ObjectType-Article-1 SourceType-Scholarly Journals-1 ObjectType-Feature-2 content type line 23
ISSN:	1530-6984 1530-6992
DOI:	10.1021/acs.nanolett.9b04598