Electronic Structure, Chemical Interactions and Molecular Orientations of 3,4,9,10-Perylene-tetracarboxylic-dianhydride on TiO2(110)
Electronic Structure, Chemical Interactions and Molecular Orientations of 3,4,9,10-Perylene-tetracarboxylic-dianhydride on TiO2(110)
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TiO2(110)上3,4,9,10-苝四甲酸二酐的电子结构、化学相互作用和分子取向
DOI：
10.1021/jp2083924
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发表时间：
2011-12-22
影响因子：
3.7
通讯作者：
Wee, Andrew T. S.
中科院分区：
文献类型：
--
作者：
Cao, Liang;Wang, Yuzhan;Wee, Andrew T. S.
利用同步辐射光电子能谱（PES）和近边X射线吸收精细结构（NEXAFS）研究了3，4，9，10-二萘嵌苯四甲酸二酐（PTCDA）分子在金红石型TiO 2（110）1 x 1表面上的电子结构、分子取向和界面能级排列. PES光谱作为PTCDA覆盖率的函数的演变被解释为可能的化学反应，强烈耦合的TiO 2表面Ti和O原子与PTCDA分子。在PTCDA的最高占据分子轨道（HOMO）的较低结合能侧观察到的界面能隙态的出现证实了PTCDA分子与TiO 2基底之间的强电子耦合。此外，PTCDA的分子取向被发现，由于强的界面相互作用的覆盖而变化。它分别在亚单层、单层和多层体系中采用略微倾斜、无序和几乎平躺的几何结构。PTCDA/TiO 2界面处的强电子耦合和相对能量排列可以促进界面电荷离域，这对于制造基于PTCDA的染料敏化太阳能电池（DSSC）器件是理想的。
The electronic structure, molecular orientations, and interfacial energy level alignment of 3,4,9,10-perylene-tetracarboxylic-dianhydride (PTCDA) molecules on rutile TiO2(110) 1 x 1 surface have been investigated using synchrotron-based photoemission spectroscopy (PES) and near-edge X-ray absorption fine structure (NEXAFS) spectroscopy. The evolution of PES spectra as a function of PTCDA coverage is interpreted as possible chemical reactions that strongly couple the TiO2 surface Ti and O atoms with PTCDA molecules. The emergence of an interfacial gap state observed at the lower binding energy side of the highest occupied molecular orbital (HOMO) of PTCDA corroborates the strong electronic coupling between PTCDA molecules and TiO2 substrate. In addition, the molecular orientation of PTCDA is found to vary with coverage due to the strong interfacial interactions. It adopts a slightly tilting, disordered, and nearly lying-down geometry in the submonolayer, monolayer, and multilayer regimes, respectively. The strong electronic coupling and the relative energy alignment at the PTCDA/TiO2 interface could facilitate the interfacial charge delocalization, which is desirable for making PTCDA-based dyesensitized solar cell (DSSC) devices.