Giant Optical Anisotropy in a Covalent Molybdenum Tellurite via Oxyanion Polymerization

Tianhui Wu; Xingxing Jiang; Kaining Duanmu; Chao Wu; Zheshuai Lin; Zhipeng Huang; Mark G Humphrey; Chi Zhang

doi:10.1002/advs.202306670

Giant Optical Anisotropy in a Covalent Molybdenum Tellurite via Oxyanion Polymerization

Adv Sci (Weinh). 2024 Mar;11(12):e2306670. doi: 10.1002/advs.202306670. Epub 2024 Jan 30.

Authors

Tianhui Wu^{1

2

3}, Xingxing Jiang⁴, Kaining Duanmu³, Chao Wu³, Zheshuai Lin⁴, Zhipeng Huang³, Mark G Humphrey^{1

5}, Chi Zhang^{1

3}

Affiliations

¹ China-Australia Joint Research Center for Functional Molecular Materials, School of Materials Science and Engineering, Ocean University of China, Qingdao, 266404, China.
² State Key Laboratory of Metastable Materials Science and Technology, Hebei Key Laboratory of Applied Chemistry, Yanshan University, Qinhuangdao, 066004, China.
³ School of Chemical Science and Engineering, Tongji University, Shanghai, 200092, China.
⁴ Technical Institute of Physics and Chemistry, Chinese Academy of Sciences, Beijing, 100190, China.
⁵ Research School of Chemistry, Australian National University, Canberra, ACT, 2601, Australia.

Abstract

Large birefringence is a crucial but hard-to-achieve optical parameter that is a necessity for birefringent crystals in practical applications involving modulation of the polarization of light in modern opto-electronic areas. Herein, an oxyanion polymerization strategy that involves the combination of two different types of second-order Jahn-Teller distorted units is employed to realize giant anisotropy in a covalent molybdenum tellurite. Mo(H₂O)Te₂O₇ (MTO) exhibits a record birefringence value for an inorganic UV-transparent oxide crystalline material of 0.528 @ 546 nm, which is also significantly larger than those of all commercial birefringent crystals. MTO has a UV absorption edge of 366 nm and displays a strong powder second-harmonic generation response of 5.4 times that of KH₂PO₄. The dominant roles of the condensed polytellurite oxyanions [Te₈O₂₀]^8- in combination with the [MoO₆]^6- polyhedra in achieving the giant birefringence in MTO are clarified by structural analysis and first-principles calculations. The results suggest that polymerization of polarizability-anisotropic oxyanions may unlock the promise of birefringent crystals with exceptional birefringence.

Keywords: birefringent crystal; molybdenum tellurite; optical anisotropy; second‐order Jahn–Teller effect; structure‐property relationships.

Abstract

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