Density-matrix approach for the electroluminescence of molecules in a scanning tunneling microscope.
Density-matrix approach for the electroluminescence of molecules in a scanning tunneling microscope.
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DOI：
10.1103/physrevlett.106.177401
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发表时间：
2010-12
影响因子：
8.6
通讯作者：
Guangjun Tian;Ji-Cai Liu;Yi Luo
中科院分区：
文献类型：
--
作者：
Guangjun Tian;Ji-Cai Liu;Yi Luo
在扫描隧道显微镜中，被限制在纳米腔内的分子的电致发光（EL）具有许多有趣但无法解释的特征。本文提出了一种基于密度矩阵形式的通用理论方法来描述金属表面附近分子在电子隧穿和局域表面等离子激元同时激发下产生的电子辐射。它揭示了外部偏置依赖性电致发光的潜在物理机制。强调了局域表面等离子体在电致发光中的重要作用。卟啉衍生物的计算重现了相应的实验光谱，并很好地解释了观测到的异常大的发射光谱变化。这种通用的理论方法在分子电子和光子器件的设计中有许多应用。
The electroluminescence (EL) of molecules confined inside a nanocavity in the scanning tunneling microscope possesses many intriguing but unexplained features. We present here a general theoretical approach based on the density-matrix formalism to describe the EL from molecules near a metal surface induced by both electron tunneling and localized surface plasmon excitations simultaneously. It reveals the underlying physical mechanism for the external bias dependent EL. The important role played by the localized surface plasmon on the EL is highlighted. Calculations for porphyrin derivatives have reproduced corresponding experimental spectra and nicely explained the observed unusual large variation of emission spectral profiles. This general theoretical approach can find many applications in the design of molecular electronic and photonic devices.