Blatnik Matthias A, Calcinelli Fabio, Jeindl Andreas, Eder Moritz, Schmid Michael, Čechal Jan, Diebold Ulrike, Jacobson Peter, Hofmann Oliver T, Wagner Margareta
Institute of Applied Physics, TU Wien 1040 Vienna Austria
CEITEC - Central European Institute of Technology, Brno University of Technology 612 00 Brno Czech Republic.
J Mater Chem C Mater. 2025 Jul 10. doi: 10.1039/d5tc01394a.
Well-ordered organic molecular layers on oxide surfaces are key for organic electronics. Using a combination of scanning tunneling microscopy (STM) and non-contact atomic force microscopy (nc-AFM) we probe the structures of copper phthalocyanine (CuPc) on InO, a model for a prototypical transparent conductive oxide (TCO). These scanning-probe images allow the direct determination of the adsorption site and distortions of the molecules, which are corroborated by DFT calculations. Isolated CuPc molecules adsorb in a flat, slightly tilted geometry in three symmetry-equivalent configurations on the stoichiometric InO(111) surface. Increasing the coverage leads to densely packed 1D chains oriented along 〈11̄0〉 directions, which dissolve into a highly ordered (2 × 2) superstructure upon increasing the CuPc density to ¾ per surface unit cell. At a coverage of one CuPc per surface unit cell, a densely packed (1 × 1) superstructure fully covers the surface. The molecules still assume the same site and orientation as before, but they partially overlap to accommodate the high packing density, leading to bending of the molecules. These results are compared to the behavior of CoPc on InO(111). In summary, we demonstrate that a uniform first layer of metal-phthalocyanine molecules can be realized on the InO(111) surface when using the proper metal atom in the molecule.
氧化物表面有序的有机分子层是有机电子学的关键。我们结合扫描隧道显微镜（STM）和非接触原子力显微镜（nc-AFM），研究了酞菁铜（CuPc）在InO上的结构，InO是一种典型透明导电氧化物（TCO）的模型。这些扫描探针图像能够直接确定分子的吸附位点和畸变情况，密度泛函理论（DFT）计算证实了这些结果。孤立的CuPc分子以平面、略微倾斜的几何构型吸附在化学计量比的InO(111)表面上，存在三种对称等效的构型。增加覆盖率会导致沿〈11̄0〉方向排列的密集一维链，当CuPc密度增加到每个表面单位晶胞¾时，这些链会溶解成高度有序的(2 × 2)超结构。在每个表面单位晶胞覆盖一个CuPc时，则会形成完全覆盖表面的密集(1 × 1)超结构。分子仍采用与之前相同的位点和取向，但它们会部分重叠以适应高堆积密度，从而导致分子弯曲。将这些结果与CoPc在InO(111)上的行为进行了比较。总之，我们证明，当在分子中使用合适的金属原子时，可以在InO(111)表面实现均匀的金属酞菁分子第一层。
