Giant Optical Anisotropy in a Covalent Molybdenum Tellurite via Oxyanion Polymerization.

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.

SUBMITTER: Wu T 

PROVIDER: S-EPMC10966567 | biostudies-literature | 2024 Mar

REPOSITORIES: biostudies-literature