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Eu5ZnGa6S15, Eu5Zn3Ga2Sn2S15, and Pb5HgGa6S15: Crystal Chemistry and Nonlinear Optical Properties
Xu-Bin Ni1, Qiu-Yang Du1, Wen-Dong Yao1
1School of Chemistry and Materials, Yangzhou University, Yangzhou225002, P. R. China.
Abstract:
The strategy of structural transformation from centrosymmetric (CS) to noncentrosymmetric (NCS) has been proved to be highly effective for exploring new nonlinear optical (NLO) materials. By introducing other tetra-coordinated cations Zn, Hg, and Sn into MGa2S4 (M = Pb, Eu) (0), a series of new multinary metal sulfides Eu5ZnGa6S15 (1), Eu5Zn3Ga2Sn2S15 (2), and Pb5HgGa6S15 (3) were obtained, which realize the CS-NCS structural transformation. 1-3 crystallize with the orthorhombic polar Ama2 space group and feature hybrid T2-supertetrahedral structure. They exhibit phase matchable NLO responses of 0.24-1.58 × AgGaS2, moderate band gaps of 2.08-2.28 eV, improved laser-induced damage thresholds of 1.37-1.63 × AgGaS2, and appropriate birefringence of 0.057-0.063. The outstanding NLO properties of 3 can be attributed to the Hg/Ga-mixed T2-supertetrahedral clusters, which is verified by the theoretical calculations.
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