Energy level alignment and electronic properties at weakly-reactive interfaces for organic electronics

这个项目的目标是获得关于由pi共轭有机分子组成的异质结的基本电子性质和平衡机制的全面知识，尽管这与有机电子学有关，但仍然缺乏。我们建议用正反光电子能谱来确定金属单晶衬底支撑的有机、碱卤化物和氧化物中间层薄膜上有机分子吸附形成的界面处的电子结构和达到电子平衡的相关机制。低能电子衍射和扫描隧道显微镜将被用来确定这些体系的结构性质。我们将把pi共轭有机分子的关键性质(即电离能、电子亲和力和轨道简并度)和层间分子的关键性质(即功函数、薄膜厚度和介电常数)与所产生的能级排列进行定量关联。这些数据将作为发展理论框架的基准，以解释观察到的电子结构，包括费米-狄拉克统计、静电学和特定界面效应。因此，我们的目标是揭示在弱耦合实体形成界面时建立电子平衡的基本机制，并提供一个能够准确预测此类系统能级排列的模型。

The goal of this project is to acquire comprehensive knowledge about the fundamental electronic properties and equilibration mechanisms at heterojunctions comprising pi-conjugated organic molecules, which, despite the relevance for organic electronics, is still lacking. We propose to use direct and inverse photoemission to determine the electronic structure and the associated mechanisms of reaching electronic equilibrium at interfaces formed by organic molecules adsorbed on organic, alkali-halide, and oxide interlayer thin films supported by metal single-crystal substrates. Low energy electron diffraction and scanning tunneling microscopy will be employed to determine the structural properties of these systems. We will correlate quantitatively key properties of the pi-conjugated organic molecules (i.e., ionization energy, electron affinity, and orbital degeneracy) and those of the interlayers (i.e., work function, film thickness, and dielectric constant) with the resulting energy level alignment. The data will serve as benchmark for the development of a theoretical framework to explain the observed electronic structure, including Fermi-Dirac statistics, electrostatics, and interface-specific effects. We thus aim to unravel the fundamental mechanisms that establish electronic equilibrium upon formation of interfaces from weakly coupled entities and to provide a model that is able to accurately predict the energy level alignment for such systems.