Wu Chao, Jiang Xingxing, Wang Zujian, Sha Hongyuan, Lin Zheshuai, Huang Zhipeng, Long Xifa, Humphrey Mark G, Zhang Chi
China-Australia Joint Research Center for Functional Molecular Materials, School of Chemical Science and Engineering, Tongji University, Shanghai, 200092, China.
Technical Institute of Physics and Chemistry, Chinese Academy of Sciences, Beijing, 100190, China.
Angew Chem Int Ed Engl. 2021 Jun 25;60(27):14806-14810. doi: 10.1002/anie.202102992. Epub 2021 May 14.
Wide ultraviolet (UV) transparency, strong second-harmonic generation (SHG) response, and sufficient optical birefringence for phase-matching (PM) at short SHG wavelengths are vital for practical UV nonlinear optical (NLO) materials. However, simultaneously optimizing these properties is a major challenge, particularly for metal phosphates. Herein, we report a non-traditional π-conjugated cation-based UV NLO phosphate [C(NH ) ] (PO ) ⋅3 H O (GPO) with a short UV cutoff edge. GPO is SHG active at 1064 nm (3.8 × KH PO @ 1064 nm) and 532 nm (0.3 × β-BaB O @ 532 nm) and also possesses a significant birefringence (0.078 @ 546 nm) with a band gap >6.0 eV. The PM SHG capability of GPO can extend to 250 nm, indicating GPO is a promising UV solar-blind NLO material. Calculations and crystal structure analysis show that the rare coexistence of wide UV transparency, large SHG response, and optical anisotropy is due to the introduction of π-conjugated cations [C(NH ) ] and their favorable arrangement with [PO ] anions.
宽紫外（UV）透明性、强二次谐波产生（SHG）响应以及在短SHG波长下实现相位匹配（PM）所需的足够光学双折射对于实用的紫外非线性光学（NLO）材料至关重要。然而，同时优化这些特性是一项重大挑战，特别是对于金属磷酸盐而言。在此，我们报道了一种具有短紫外截止边的基于非传统π共轭阳离子的紫外NLO磷酸盐[C(NH₂)₃]₃(PO₄)₂·3H₂O（GPO）。GPO在1064 nm（3.8×KH₂PO₄@1064 nm）和532 nm（0.3×β-BaB₂O₄@532 nm）处具有SHG活性，并且在546 nm处还具有显著的双折射（0.078），带隙>6.0 eV。GPO的PM SHG能力可延伸至250 nm，表明GPO是一种有前途的紫外日盲NLO材料。计算和晶体结构分析表明，宽紫外透明性、大SHG响应和光学各向异性的罕见共存是由于引入了π共轭阳离子[C(NH₂)₃]及其与[PO₄]阴离子的有利排列。
