Metal-Organic Layers with an Enhanced Two-Photon Absorption Cross-Section and Up-Converted Emission
Metal-Organic Layers with an Enhanced Two-Photon Absorption Cross-Section and Up-Converted Emission
复制标题
具有增强的双光子吸收截面和上转换发射的金属有机层
DOI：
10.1021/acs.chemmater.0c03457
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发表时间：
2021-02-15
影响因子：
8.6
通讯作者：
Wang, Cheng
中科院分区：
文献类型：
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作者：
Hu, Xuefu;Wang, Zhiye;Wang, Cheng
许多发色团的双光子吸收(TPA)可以通过将它们构建在金属有机骨架(MOF)的结构中来增强。然而，MOF的光散射使光束散焦，从而降低了像TPA那样的非线性光学效应。纳米级二维金属有机薄膜(MOLS)是具有低光散射的二维金属有机薄膜的类似物。在这项工作中，我们得到了含有三(4-羧基联苯)-4‘-胺(H(3)TCBPA)的MOL，其TPA截面积为13000+/-2000GM，与H(3)TCBPA配体在均相溶液中的TPA截面积(1850+/-200GM)的7倍相似。由于高效的TPA和高的荧光量子产率，MOL还发出了明亮的上转换荧光。理论计算表明，由于配体和金属连接节点之间的电子重新分布，激发态偶极矩较大，是TPA增强的原因。这项工作说明了MOLS是具有增强的TPA的2D材料，用于产生明亮的上转换荧光。
Two-photon absorption (TPA) of many chromophores can be enhanced by building them into the structure of metal-organic frameworks (MOFs). However, light scattering of MOFs defocuses the light beam and thus decreases the nonlinear optical effects like TPA. Nanoscale two-dimensional (2D) metal-organic layers (MOLs) are 2D analogues of MOFs with low light scattering. In this work, we obtained a MOL containing tri(4-carboxylic-biphenyl)-4'-amine (H(3)TCBPA) that exhibited a TPA cross-section of 13 000 +/- 2000 GM, which is similar to 7 times that of the H(3)TCBPA ligand in homogeneous solution (1850 +/- 200 GM). The MOL also gave bright up-converted fluorescence thanks to efficient TPA and a high fluorescence quantum yield. The theoretical calculation showed that a large dipole moment of the excited state due to electron redistribution between the ligands and the metal-connecting nodes in the MOL is the reason for the TPA enhancement. This work illustrates MOLs as 2D materials with enhanced TPA for generating bright upconverted fluorescence.