纳腔等离激元对分子上和分子旁边的隧穿电子诱导发光的作用研究

本文使用含时量子主方程，从理论上计算了当分子或者等离激元分别被激发的情形下等离激元-分子耦合体系发光特性的时间和光谱演化，并在此基础上讨论了纳腔等离激元在扫描隧道显微镜（STM）诱导发光中发挥的不同作用.当STM针尖在分子上方，隧穿电子可以直接激发分子时，纳腔等离激元的主要作用是通过提高分子的辐射速率来增强其发光，此时耦合体系表现出具有分子特征的尖锐发光峰.另一方面，当STM针尖非常靠近分子边缘但没有载流子注入直接激发分子时，等离激元-分子之间的相干耦合会在这两个量子客体之间产生相消干涉，导致在分子激子能量附近出现法诺共振，使我们观察到具有法诺凹谷特征的等离激元发光光谱.

Role of Nanocavity Plasmons in Tunneling Electron Induced Light Emission on and near a Molecule

By using a microscopic quantum model, we study theoretically different roles of nanocavity plasmons in scanning tunneling microscope (STM) induced light emission upon selective initial excitation of molecules or plasmons. The time evolution and spectroscopic properties of the emission from the coupled plasmon-molecule system in each case are studied using time-dependent quantum mater equations. When the STM tip is placed on the molecule to ensure direct carrier injection induced molecular excitation, the major role of the plasmons is to enhance the molecular emission via increasing its radiative decay rate, resulting in sharp molecule-specific emission peaks. On the other hand, when the STM tip is located in close proximity to the edge of the molecule but without direct carrier injection into the molecule, the role of the plasmon-molecule coupling is to cause destructive interferences between the two quantum objects, leading to the occurrence of Fano dips around the energy of the molecular exciton in the plasmonic emission spectra.