The aim of molecular electronics is to miniaturize active electronic devices and ultimately construct single-molecule nanocircuits using molecules with diverse structures featuring various functions, which is extremely challenging. Here, we realize a gate-controlled rectifying function (the on/off ratio reaches ∼60) and a high-performance field effect (maximum on/off ratio >100) simultaneously in an initially symmetric single-molecule photoswitch comprising a dinuclear ruthenium-diarylethene (Ru-DAE) complex sandwiched covalently between graphene electrodes. Both experimental and theoretical results consistently demonstrate that the initially degenerated frontier molecular orbitals localized at each Ru fragment in the open-ring Ru-DAE molecule can be tuned separately and shift asymmetrically under gate electric fields. This symmetric orbital shifting (AOS) lifts the degeneracy and breaks the molecular symmetry, which is not only essential to achieve a diode-like behavior with tunable rectification ratio and controlled polarity, but also enhances the field-effect on/off ratio at the rectification direction. In addition, this gate-controlled symmetry-breaking effect can be switched on/off by isomerizing the DAE unit between its open-ring and closed-ring forms with light stimulus. This new scheme offers a general and efficient strategy to build high-performance multifunctional molecular nanocircuits.

中文翻译：

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稳定和光开关单分子结中的可调谐对称破坏诱导双重功能

分子电子学的目标是使有源电子器件小型化，最终利用结构多样、功能多样的分子构建单分子纳米电路，极具挑战性。在这里，我们在包含双核钌的初始对称单分子光开关中同时实现了门控整流功能（开/关比达到~60）和高性能场效应（最大开/关比> 100）。二芳基乙烯 (Ru-DAE) 复合物共价夹在石墨烯电极之间。实验和理论结果一致表明，位于开环Ru-DAE分子中每个Ru片段的最初退化的前沿分子轨道可以在栅极电场下单独调整和不对称移动。这种对称轨道位移 (AOS) 提升了简并性并打破了分子对称性，这不仅对于实现具有可调整流比和可控极性的二极管类行为至关重要，而且还提高了整流时的场效应开/关比方向。此外，这种门控对称破坏效应可以通过光刺激在其开环和闭环形式之间异构化 DAE 单元来打开/关闭。这种新方案为构建高性能多功能分子纳米电路提供了一种通用且有效的策略。此外，这种门控对称破坏效应可以通过光刺激在其开环和闭环形式之间异构化 DAE 单元来打开/关闭。这种新方案为构建高性能多功能分子纳米电路提供了一种通用且有效的策略。此外，这种门控对称破坏效应可以通过光刺激在其开环和闭环形式之间异构化 DAE 单元来打开/关闭。这种新方案为构建高性能多功能分子纳米电路提供了一种通用且有效的策略。