Departamento de Física Teórica de la Materia Condensada, Universidad Autónoma de Madrid, E-28049 Madrid, Spain and Condensed Matter Physics Center (IFIMAC), Universidad Autónoma de Madrid, E-28049 Madrid, Spain and Departamento de Física Aplicada I, Escuela Politécnica Superior, Universidad de Sevilla, Seville, E-41011, Spain.
IMDEA Nanociencia, Ciudad Universitaria de Cantoblanco, E-28049 Madrid, Spain.
Phys Chem Chem Phys. 2020 Mar 11;22(10):5638-5646. doi: 10.1039/c9cp06384f.
We have joined two fundamental concepts of organic chemistry to provide a deep, yet intuitive, understanding of how side groups influence destructive quantum interference (DQI) in the transport through conjugated molecules. Using density functional theory combined with Green's function techniques, and employing tight-binding models in which all the π-systems are considered, we elucidate the separate roles of bond-resonance and induction in tuning DQI. We show that the position of the anti-resonances produced by DQI is sensitive to the number of side groups, but not in a simple additive way. Instead, addition of multiple groups results in a weaker overall contribution per group, and this can be understood using a straight forward graphical analysis. Furthermore, we show that additional fine tuning of DQI is possible via attachment of a chain of atoms to a second site around the ring. DQI is controlled by modifying the length of the chain, thus providing exquisite control over the anti-resonance position. This insight provides chemists with a large number of options to tune DQI for unprecedented device optimization.
我们融合了有机化学的两个基本概念，为深入理解侧基如何影响共轭分子中破坏性量子干涉（DQI）的传输提供了直观的认识。我们采用密度泛函理论结合格林函数技术，并采用紧束缚模型，其中所有的π 体系都被考虑在内，阐明了键共振和诱导在调谐 DQI 方面的单独作用。我们表明，由 DQI 产生的反共振的位置对侧基的数量敏感，但不是以简单的加和方式。相反，多个基团的添加导致每个基团的整体贡献减弱，这可以通过直观的图形分析来理解。此外，我们还表明，通过在环周围的第二个位置附加原子链，可以对 DQI 进行额外的微调。通过改变链的长度来控制 DQI，从而可以对反共振位置进行精确控制。这一见解为化学家提供了大量的选项来调谐 DQI，以实现前所未有的器件优化。
