卟啉-碳硼烷-硼亚甲基二吡咯三元化合物二阶非线性光学性质的理论研究

采用密度泛函理论(DFT)方法对卟啉-碳硼烷-硼亚甲基二吡咯(BODIPY)三元化合物的几何结构、 吸收光谱及二阶非线性光学(NLO)特性进行计算分析. 结果表明, V型化合物的静态第一超极化率(β_tot)大于相应直线型化合物, 且延长共轭链可提高体系的β_tot. 分析体系的电子密度差分图得出, 化合物氧化还原态的电荷转移方式与本征态相比发生了改变, 从而使其二阶NLO性质发生明显变化. 含频第一超极化率计算结果表明, 在一定范围内频率对化合物有较小的色散效应. 因此, 通过延长二维化合物的共轭链及氧化还原反应, 可以有效调控其二阶NLO响应.

Theoretical Study on the Second-order Nonlinear Optical Properties of a Porphyrin-o-Carborane-Boron-dipyrromethene Triad Compound†

The calculations of geometric structures, electronic absorption spectra, second-order nonlinear optical(NLO) properties of porphyrin-o-carborane-boron-dipyrromethene(BODIPY) triad were carried out by density functional theory(DFT). The results show that the static first hyperpolarizability(β_tot) of the V-shaped compound is larger than that of the linear-shaped compound, and the β_tot values can be enhanced by extending π-conjugate bridge. The analysis of electron density difference maps can be seen that the charge transfer pattern of the oxidized/reduced species have changed, which lead to the second-order NLO properties have significantly varied. The investigation of the frequency-dependent first hyperpolarizability shown that less dispersion effect at restrictive frequency region for all of the compounds. Therefore, second-order NLO properties can be effectively modulated by extending π-conjugate bridge and oxidized/reduced reactions.