This study presents the design, synthesis, and comprehensive characterization of a novel series of D‐π‐A type malononitrile‐derived chromophores, BTC‐1 to BTC‐4. Combining various spectroscopic techniques, nonlinear Z‐scan measurements, and quantum chemical calculations, we revealed the intricate relationship between nonlinear optical properties and the interplay of molecular structure, intramolecular charge transfer (ICT), and dipole moments (μ). Our experimental and computational findings corroborate that the polarization degree in the ground state, the charge separation in the excited state and ICT collectively dictate the nonlinear optical properties of the compounds. Notably, BTC‐1 exhibits an exceptional nonlinear absorption coefficient β value (2 × 10‐8 m W‐1), attributed to its optimized charge transfer efficiency and pronounced degree of charge separation. Our findings provide actionable insights for the rational design of high‐performance organic NLO materials with potential applications in advanced photonic devices.

中文翻译：

---

揭示扭曲芳香供体对 D-π-A 型丙二腈衍生发色团非线性响应的影响


本研究介绍了一系列新型 D-π-A 型丙二腈衍生发色团 BTC-1 至 BTC-4 的设计、合成和综合表征。结合各种光谱技术、非线性 Z 扫描测量和量子化学计算，我们揭示了非线性光学特性与分子结构、分子内电荷转移 (ICT) 和偶极矩 (μ) 相互作用之间的复杂关系。我们的实验和计算结果证实了基态的偏振度、激发态的电荷分离和ICT共同决定了化合物的非线性光学性质。值得注意的是，BTC-1 表现出出色的非线性吸收系数 β 值 (2 × 10-8 m W-1)，这归因于其优化的电荷转移效率和显着的电荷分离程度。我们的研究结果为高性能有机非线性光学材料的合理设计提供了可行的见解，并在先进光子器件中具有潜在的应用。