Li Xintong, Chen Linjie, Wang Zehua, Li Andi, Xu Huimin, Shen Guangzhen, Liu Jianyi, Cui Xuefeng, Tan Shijing, Zhao Jin, Apkarian V Ara, Wang Bing, Petek Hrvoje
Hefei National Research Center for Physical Sciences at the Microscale and New Cornerstone Science Laboratory, University of Science and Technology of China, Hefei, Anhui 230026, China.
Hefei National Laboratory, University of Science and Technology of China, Hefei, Anhui 230088, China.
J Am Chem Soc. 2025 Jul 2;147(26):23286-23296. doi: 10.1021/jacs.5c08068. Epub 2025 Jun 18.
Molecular materials offer a boundless design palette for light absorption and charge transport in both natural photosynthesis and engineered photovoltaics. They function in combination as chromophores, donors, conductors, and acceptors, enabling the excitation and charge carrier transport through space and wire-like intramolecular pathways. Although quantum coherence is believed to enhance photoexcitation and photoinduced charge transfer, fluctuating and inhomogeneous environments accelerate decoherence. Here, we assemble a nanoporous medium consisting of a templated bipyridyl ethylene (BPE) molecule array on a Ag(111) surface that functions as an exceptional intermolecular nonnuclear quantum well conductor of coherent electron waves spanning over 20 Å length. Time-periodic driving of the Ag/BPE interface by femtosecond pulses promotes electrons into a ladder of Floquet quasi-energy donor states, where intermolecular quantum well states act as a resonant doorway for coherent electron transport into BPE/vacuum image potential acceptor states. The bifurcation of electron passage between the Floquet donor ladder and the charge transfer acceptor channel is recorded by projecting the active electrons into the photoemission continuum in an interferometric time- and angle-resolved multiphoton photoemission experiment. We find that exceptional decoupling of electrons from the metal substrate by the molecule-dressed vacuum preserves the coherence on the ∼150 fs time scale. This offers a new paradigm for quantum state design where a molecule-dressed vacuum mediates coherent electron transport in nanoporous molecular architectures.
分子材料为自然光合作用和工程化光伏中的光吸收和电荷传输提供了无限的设计空间。它们作为发色团、供体、导体和受体协同发挥作用，使得激发和电荷载流子能够通过空间和线状分子内路径进行传输。尽管量子相干被认为能够增强光激发和光致电荷转移，但波动且不均匀的环境会加速退相干。在此，我们在Ag(111)表面组装了一种由模板化联吡啶乙烯（BPE）分子阵列构成的纳米多孔介质，该介质作为一种特殊的分子间非核量子阱导体，可传导跨越超过20 Å长度的相干电子波。通过飞秒脉冲对Ag/BPE界面进行时间周期驱动，可将电子激发到一系列弗洛凯准能供体态中，其中分子间量子阱态充当了相干电子传输到BPE/真空镜像势受体态的共振通道。在干涉时间和角度分辨多光子光电子能谱实验中，通过将活性电子投影到光电子连续谱中，记录了电子在弗洛凯供体阶梯和电荷转移受体通道之间的通道分支情况。我们发现，由分子修饰的真空使电子与金属衬底实现了特殊的解耦，从而在约150 fs的时间尺度上保持了相干性。这为量子态设计提供了一种新范式，即分子修饰的真空在纳米多孔分子结构中介导相干电子传输。
