AI 中文总结
本研究提出一种基于针尖增强拉曼散射的量子点显微镜新方法，可实现纳米尺度静电势成像，速度快、复杂度低，与传统力谱方法定量等效，其强度变化源于分子拉曼散射共振态跃迁。
AI 中文摘要
纳米尺度静电势的量化对于理解跨多尺度材料性质的调控原理至关重要。当前最成功的方法之一依赖于分子量子点的电荷响应，该量子点悬浮在扫描探针显微镜的针尖上，通过动态力谱测量。我们研究了光学检测的可能性，旨在提高测量速度并降低方案复杂度。我们证明，集成的针尖增强拉曼散射强度与量子点的电荷状态密切相关，并用其绘制单原子的静电势图，发现其与已建立的力谱方法定量等效。我们通过测量不同激发波长和分子量子点电荷下的拉曼光谱，阐明了该新方法的潜在光物理原理，揭示观测到的拉曼强度变化主要由分子在共振与非共振拉曼散射 regime 之间的跃迁驱动。
英文摘要
Quantification of electrostatic potentials at the nanoscale is crucial for understanding the principles governing properties of materials across multiple length scales. Currently, one of the most successful approaches relies on the charging response of a molecular quantum dot, suspended on a tip of a scanning probe microscope and measured using dynamic force spectroscopy. We investigate the possibility of an optical detection, aiming to improve the speed and reduce the complexity of this measurement scheme. We show that the integrated tip-enhanced Raman scattering intensity strongly correlates with the charge state of the quantum dot, and use it to map the electrostatic potential of a single atom. A quantitative equivalence with the established force spectroscopy method is found. We address the underlying photophysical principle of this new method by measuring the Raman spectra as a function of excitation wavelength and the molecular quantum dot charge. We reveal that the observed Raman intensity variations are primarily driven by transitions between resonant and non-resonant Raman scattering regimes of the molecule.
