Unveiling the self-organization mechanism of semiconducting organic molecules onto metallic surfaces is the rst step to design hybrid devices in which the selfassembling is exploited to tailor magnetic properties. In this study, doubledecker rare-earth phthalocyanines, namely lutetium phthalocyanine (LuPc 2), are deposited on Au(111) gold surface forming large scale self-assemblies. Global and local experimental techniques, namely grazing incidence X-ray diraction and scanning tunneling microscopy, supplemented by density functional theory calculations with van der Waals corrections, give insight of the molecular structural arrangement in the thin lm and the self-organization at the surface. Our results show unambiguously that the two plateaus of the doubledecker phthalocyanine present a dierent rotation than the isolated molecule. This is evidenced by density functional theory simulations of optimized LuPc 2 monolayer showing a perfect agreement with experimental ndings. Moreover, the stabilized structure of double layers reveals an eclipsed conguration of the molecules in the stacking, having the ligand plateaus parallel to the gold surface. The high crystallinity of the molecular assembly and its weak electronic coupling with the metallic substrate is expected to open new perspective in the design of optoelectronic or magnetic devices.

Because organic electronics suffer from degradation inducing oxidation processes, oxygen tolerant organic molecules could solve this issue and be integrated to improve the stability of devices during operation. In this work, we investigate how lutetium doubledecker phthalocyanine (LuPc 2) reacts towards molecular oxygen and we report microscopic details of its interaction with LuPc 2 film by combining X-ray Photoemission Spectroscopy, Near Edge X-ray Absorption Fine Structure Spectroscopy and Density Functional Theory. Surprisingly, LuPc 2 molecules are found to weakly physisorb below 120 K and appear rather inert to molecular oxygen at more elevated temperatures. We are able to draw a microscopic picture at low temperature in which oxygen molecules stick on top of the pyrrolic carbon of LuPc 2. Our work sheds light on a class of semiconducting molecules, namely doubledecker phthalocyanines, that present a high tolerance towards molecular oxygen, opening promising perspectives for the design of stable materials to be applied in the next generation of organic based electronic devices operating under ambient conditions.

Unveiling the interplay of semiconducting organic molecules with their environment, such as inorganic materials or atmospheric gas, is the first step to designing hybrid devices with tailored optical, electronic or magnetic properties. The present article focuses on a double-decker lutetium phthalocyanine known as an intrinsic semiconducting molecule, holding a Lu ion in its center, sandwiched between two phthalocyanine rings. Carrying out experimental investigations by means of electron spectroscopies, X-ray diffraction and scanning probe microscopies together with advanced ab initio computations, allows us to unveil how this molecule interacts with weakly or highly reactive surfaces. Our studies reveal that a molecule–surface interaction is evidenced when molecules are deposited on bare silicon or on gold surfaces together with a charge transferred from the substrate to the molecule, affecting to a higher extent the lower ring of the molecule. A new packing of the molecules on gold surfaces is proposed: an eclipse configuration in which molecules are flat and parallel to the surface, even for thick films of several hundreds of nanometers. Surprisingly, a robust tolerance of the double-decker phthalocyanine toward oxygen molecules is demonstrated, leading to weak chemisorption of oxygen below 100 K.

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