Intermolecular energy-band dispersion in PTCDA multilayers
Intermolecular energy-band dispersion in PTCDA multilayers
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DOI：
10.1103/physrevb.68.033102
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发表时间：
2003-07-15
影响因子：
3.7
通讯作者：
Ueno, N
中科院分区：
文献类型：
--
作者：
Yamane, H;Kera, S;Ueno, N
采用同步辐射角分辨紫外光电子能谱研究了在MoS2单晶表面制备的良好取向的苝-3,4,9,10-四甲酸二酐多层膜的电子结构。从正常发射光谱的光子能量依赖性来看，我们观察到单个 pi 特征的最高占据分子轨道 (HOMO) 能带的分子间能带色散约为 0.2 eV。观察到的能带色散显示出一条余弦曲线，该曲线源于分子间的 pi-pi 相互作用。利用紧束缚模型分析得出，π-π相互作用的传递积分约为0.05 eV，HOMO空穴的有效质量m(h)* = 5.28m(o)，空穴迁移率mu(h) > 3.8 cm(2)/V s。这是首次观察到仅具有弱分子间范德华相互作用的传统单组分有机半导体的分子间能带色散。
The electronic structure of a well-oriented perylene-3,4,9,10-tetracarboxylic acid-dianhydride multilayer prepared on MoS2 single crystal surface were studied by angle-resolved ultraviolet photoemission spectroscopy using synchrotron radiation. From the photon energy dependence of normal emission spectra, we observed an intermolecular energy-band dispersion of about 0.2 eV for the highest occupied molecular orbital (HOMO) band of single pi character. The observed energy-band dispersion showed a cosine curve, which originates from the intermolecular pi-pi interaction. Analyses using the tight-binding model gave that the transfer integral of about 0.05 eV for the pi-pi interaction, the effective mass of HOMO hole m(h)* = 5.28m(o), and the hole mobility mu(h) > 3.8 cm(2)/V s. This is the first observation of the intermolecular energy-band dispersion of a conventional single-component organic semiconductor only with the weak intermolecular van der Waals interaction.