Structure of van der Waals bound hybrids of organic semiconductors and transition metal dichalcogenides: the case of acene films on MoS₂

Abstract

Transition metal dichalcogenides (TMDC) are important representatives in the emerging field of two‐dimensional materials. At present their combination with molecular films is discussed as it enables the realization of van der Waals bound organic/inorganic hybrids which are of interest in future device architectures. Here, we discuss the potential use of molybdenum disulfide (MoS2) as supporting substrate for the growth of well‐defined, crystalline organic adlayers. By this means, hybrid systems between the TMDC surface and organic compounds can be prepared, allowing for the profound investigation of mutual optical and electronic coupling mechanisms. As model system, we choose pentacene and perfluoropentacene as prototypical organic semiconductors and analyze their film formation on MoS2(001) surfaces. In both cases, we observe smooth, crystalline film growth in lying molecular configuration, hence enabling the preparation of well‐defined hybrid systems. By contrast, on defective MoS2 surfaces both materials adopt an upright molecular orientation and exhibit distinctly different film morphologies. This emphasizes the importance of highly ordered TMDC surfaces with low defect density for the fabrication of well‐defined hybrid systems.

Engineering of TMDC–OSC hybrid interfaces: the thermodynamics of unitary and mixed acene monolayers on MoS2

“…In contrast to the mobile molecules in the (sub-) monolayers, multilayers of PEN and PFP form crystalline films, as shown in a previous study. 32 In these films, the molecules are immobile, resulting in a larger entropy gain upon desorption and therefore a larger prefactor for desorption.…”

“…This procedure yields crystals of almost centimeter size as shown in ref. 32 . The crystals were exfoliated under ambient conditions before being evacuated.…”

“… 31 To minimize the influence of defects at the MoS 2 surface on the OSC–TMDC interface, we use pristine exfoliated MoS 2 single crystals on which we found epitaxial growth of PEN and PFP in a previous study. 32 …”

“…31 To minimize the inuence of defects at the MoS 2 surface on the OSC-TMDC interface, we use pristine exfoliated MoS 2 single crystals on which we found epitaxial growth of PEN and PFP in a previous study. 32 To study molecular desorption kinetics, we use temperatureprogrammed desorption (TPD) as a versatile technique for investigating the thermal evolution and interfacial bond strength of organic/inorganic hybrid systems. In recent years, TPD has been increasingly employed to study interfaces between large aromatic molecules and metals [33][34][35][36][37][38][39][40][41][42][43][44][45][46][47][48] or graphite.…”

Engineering of TMDC-OSC Hybrid Interfaces: The Thermodynamics of Unitary and Mixed Acene Monolayers on MoS2

“…31 To minimize the influence of defects at the MoS2 surface on the OSC-TMDC interface, we use pristine exfoliated MoS2 single crystals on which we found epitaxial growth of PEN and PFP in a previous study. 32 To study molecular desorption kinetics, we use temperatureprogrammed desorption (TPD) as a versatile technique for investigating the thermal evolution and interfacial bond strength of organic/inorganic hybrid systems. In recent years, TPD has been increasingly employed to study interfaces between large aromatic molecules and metals [33][34][35][36][37][38][39][40][41][42][43][44][45][46][47][48] or graphite.…”