K2Au(IO3)5 and β‐KAu(IO3)4: Polar Materials with Strong SHG Responses Originating from Synergistic Effect of AuO4 and IO3 Units
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| Authors: | Dr Xiang Xu Dr Chun‐Li Hu Bing‐Xuan Li Prof Dr Jiang‐Gao Mao |
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| Institution: | 1. State Key Laboratory of Structural Chemistry, Fujian Institute of Research on the Structure of Matter, Chinese Academy of Sciences, Fuzhou, P.R. China), Fax;2. Key Laboratory of Optoelectronic Materials Chemistry and Physics, Fujian Institute of Research on the Structure of Matter, Chinese Academy of Sciences, Fuzhou, P.R. China;3. +86)?591‐6317‐3121 |
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| Abstract: | Two new polar potassium gold iodates, namely, K2Au(IO3)5 (Cmc21) and β‐KAu(IO3)4 (C2), have been synthesized and structurally characterized. Both compounds feature zero‐dimensional polar Au(IO3)4]? units composed of an AuO4 square‐planar unit coordinated by four IO3? ions in a monodentate fashion. In β‐KAu(IO3)4, isolated Au(IO3)4]? ions are separated by K+ ions, whereas in K2Au(IO3)5, isolated Au(IO3)4]? ions and non‐coordinated IO3? units are separated by K+ ions. Both compounds are thermally stable up to 400 °C and exhibit high transmittance in the NIR region (λ=800–2500 nm) with measured optical band gaps of 2.65 eV for K2Au(IO3)5 and 2.75 eV for β‐KAu(IO3)4. Powder second‐harmonic generation measurements by using λ=2.05 μm laser radiation indicate that K2Au(IO3)5 and β‐KAu(IO3)4 are both phase‐matchable materials with strong SHG responses of approximately 1.0 and 1.3 times that of KTiOPO4, respectively. Theoretical calculations based on DFT methods confirm that such strong SHG responses originate from a synergistic effect of the AuO4 and IO3 units. |
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| Keywords: | iodine polar material second-harmonic generation single-crystal structures synergistic effects |
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