Sapienza University of Rome, Piazzale Aldo Moro, 5, I-00185 Rome, Italy.
ALBA Synchrotron Light Source, Carrer de la Llum, 2-26, E-08290 Barcelona, Spain.
J Chem Phys. 2019 Feb 7;150(5):054704. doi: 10.1063/1.5080533.
The assembling of metal phthalocyanines on the rippled moiré superlattice of graphene/Ir(111) intercalated with one Co layer is driven by the site-dependent polarization field induced by the incommensurate graphene-Co interface. We have performed an X-ray absorption and photoemission study to unveil the role of the metallic centers and of the organic ligands in the molecule-Co interaction process mediated by graphene. Notably, we consider different electronic molecular orbitals, i.e. phthalocyanines with Cu and Mn metallic ions. The spectroscopic response suggests almost unaltered CuPc molecular states upon adsorption, and the rippled graphene carpet decouples completely the electronic interaction between the molecules and the Co layer, while a slight hybridization is present for MnPcs. MnPc molecules, trapped in the valleys of the moiré graphene superlattice, slightly intermix, through the orbitals protruding out of the molecular plane, with the underlying Co, while the organic ligands are almost unaltered. Graphene acts as an interlayer and mediates the interaction between metal phthalocyanines and the metallic substrate, preventing a strong chemical intermixing and enabling the assembly of almost unaltered molecules, preserving their electronic/magnetic state.
在波纹莫尔超晶格上组装金属酞菁，该超晶格是由一层 Co 原子嵌入的石墨烯/Ir(111)形成的，其驱动力是由石墨烯-Co 界面的非共形引起的位置相关的极化场。我们进行了 X 射线吸收和光电子能谱研究，以揭示金属中心和有机配体在石墨烯介导的分子-Co 相互作用过程中的作用。值得注意的是，我们考虑了不同的电子分子轨道，即具有 Cu 和 Mn 金属离子的酞菁。光谱响应表明，吸附后 CuPc 分子状态几乎没有变化，波纹石墨烯地毯完全解耦了分子和 Co 层之间的电子相互作用，而 MnPcs 则存在轻微的杂化。MnPc 分子被困在波纹石墨烯超晶格的谷中，通过分子平面外的轨道与底层 Co 略微混合，而有机配体几乎没有变化。石墨烯作为层间物质，介导了金属酞菁和金属基底之间的相互作用，防止了强烈的化学混合，并使几乎未改变的分子组装成为可能，保持了它们的电子/磁性状态。
