低维有机/无机杂化界面的理性设计以增强二次谐波产生

中文摘要 AI 辅助

由推-拉有机分子物理吸附在二维半导体上形成的杂化界面为工程化二次谐波产生提供了一个结构可调的平台。然而，由于吸附层和基底非线性响应之间的相位敏感干涉，预测和优化其宏观响应仍然是一个艰巨的挑战。在此，我们开发了一个物理信息计算筛选框架，将有效二阶极化率分解为其组成的基底、分子和电场诱导的二次谐波通道。通过跨代表性界面结构的全原子第一性原理计算验证，该模型映射了在具有不同对称性的二维基底上化学调制的碳共轭极性分子的完整取向分辨张量景观。关键的是，我们的发现打破了传统上对静态极性描述符的依赖，证明基态永久偶极矩大小从根本上来说是宏观非线性响应的不可靠代理。相反，我们表明二次谐波最大化的最终标准编码在全各向异性分子超极化率张量的相位分辨投影中。在非中心对称基底上，物理吸附层与底层二维矩阵之间的相干干涉诱导了特征性的法诺样不对称性和排序反转，而这些在中心对称平台上完全不存在。通过确立功能化拓扑、动态空间取向和基底点群对称性构成一个单一的、不可分离的参数空间，这项工作为下一代低维杂化材料用于非线性光电子学的理性组装、预测性发现和非侵入性表征提供了系统性蓝图。

英文摘要

Hybrid interfaces formed by push-pull organic molecules physisorbed on two-dimensional (2D) semiconductors provide a structurally tunable platform for engineering second-harmonic generation (SHG). However, predicting and optimizing their macroscopic response remains a formidable challenge due to the phase-sensitive interference between the nonlinear responses of the adlayer and substrate. Here, we develop a physics-informed computational screening framework that decomposes the effective second-order susceptibility into its constituent substrate, molecular, and electric-field-induced SHG channels. Validated by fully atomistic first-principles calculations across representative interface structures, this model maps the complete orientation-resolved tensor landscape of chemically modulated carbon-conjugated polar molecules on 2D substrates with distinct symmetry. Crucially, our findings dismantle the conventional reliance on static polar descriptors, demonstrating that the ground-state permanent dipole magnitude is a fundamentally unreliable proxy for macroscopic nonlinear response. Instead, we show that the ultimate criterion for SHG maximization is encoded in the phase-resolved projection of the full anisotropic molecular hyperpolarizability tensor. On non-centrosymmetric substrates, the coherent interference between the physisorbed adlayer and the underlying 2D matrix induces a characteristic Fano-like asymmetry and ranking reversals that are entirely absent on centrosymmetric platforms. By establishing that functionalization topology, dynamic spatial orientation, and substrate point-group symmetry constitute a single, non-separable parameter space, this work provides a systematic blueprint for the rational assembly, predictive discovery, and non-invasive characterization of next-generation low-dimensional hybrid materials for nonlinear optoelectronics.

发表机构

• Friedrich-Schiller-Universität Jena（耶拿弗里德里希·席勒大学）

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