Structural Determination and Nonlinear Optical Properties of New 1T‴-Type MoS2 Compound

Yuqiang Fang; Xiaozong Hu; Wei Zhao; Jie Pan; Dong Wang; Kejun Bu; Yuanlv Mao; Shufen Chu; Pan Liu; Tianyou Zhai; Fuqiang Huang

doi:10.1021/jacs.8b12133

Structural Determination and Nonlinear Optical Properties of New 1T‴-Type MoS₂ Compound

J Am Chem Soc. 2019 Jan 16;141(2):790-793. doi: 10.1021/jacs.8b12133. Epub 2019 Jan 4.

Authors

Yuqiang Fang^{1

2}, Xiaozong Hu³, Wei Zhao¹, Jie Pan¹, Dong Wang¹, Kejun Bu^{1

2}, Yuanlv Mao^{1

2}, Shufen Chu⁴, Pan Liu⁴, Tianyou Zhai³, Fuqiang Huang^{1

5}

Affiliations

¹ State Key Laboratory of High Performance Ceramics and Super fine Microstructure , Shanghai Institute of Ceramics, Chinese Academy of Sciences , Shanghai 200050 , China.
² University of Chinese Academy of Sciences , Beijing 100049 , China.
³ State Key Laboratory of Material Processing and Die & Mould Technology, School of Materials Science and Technology , Huazhong University of Science and Technology (HUST) , Wuhan 430074 , China.
⁴ State Key Laboratory of Metal Matrix Composites, School of Materials Science and Engineering , Shanghai Jiao Tong University , Shanghai 200030 , China.
⁵ State Key Laboratory of Rare Earth Materials Chemistry and Applications, College of Chemistry and Molecular Engineering , Peking University , Beijing 100871 , China.

PMID: 30601005
DOI: 10.1021/jacs.8b12133

Abstract

Noncentrosymmetric MoS₂ semiconductors (1H, 3R) possess not only novel electronic structures of spin-orbit coupling (SOC) and valley polarization but also remarkable nonlinear optical effects. A more interesting noncentrosymmetric structure, the so-called 1T‴-MoS₂ layers, was predicted to be built up from [MoS₆] octahedral motifs by theoreticians, but the bulk 1T‴ MoS₂ or its single crystal structure has not been reported yet. Here, we have successfully harvested 1T‴ MoS₂ single crystals by a topochemical method. The new layered structure is determined from single-crystal X-ray diffraction. The crystal crystallizes in space group P3₁m with a cell of a = b = 5.580(2) Å and c = 5.957(2) Å, which is a √3 a × √3 a superstructure of 1T MoS₂ with corner-sharing Mo₃ triangular trimers observed by the STEM. 1T‴ MoS₂ is verified to be semiconducting and possesses a band gap of 0.65 eV, different from metallic nature of 1T or 1T' MoS₂. More surprisingly, the 1T‴ MoS₂ does show strong optical second-harmonic generation signals. This work provides the first layered noncentrosymmetric semiconductor of edge-sharing MoS₆ octahedra for the research of nonlinear optics.