UNIVERSITY OF COLOGNE

Focus area A addresses the synthesis of pi-conjugated molecular building blocks (MBB) with varying templating capabilities. In TIDE, the rationale for the selection of the materials used for templating is guided by the necessity to use (semi-)rigid, anisotropic MBBs to reduce their degrees of freedom in conformation, having in mind the naïve concept of building a brick wall. At the same time, the molecules should provide the desired optoelectronic functionalities, e.g. absorption and/or emission in the solid state (thin film).

A1.2 – Prof. Arne Lützen: Synthesis and supramolecular organisation of chiral pi-conjugated small molecules

A2.2 – Prof. Sigurd Höger: Scanning tunnelling microscopy investigation of polygonal arylene-alkynylene macrocycles that pre-organize attached polyaromatic hydrocarbon groups

Focus Area B deals with the synthesis of 2D and 3D templates, which shall enable ordered growth of molecules on top. We propose to use graphene, hBN and graphene nanoribbons as 2D templating substrates. Due to their ultrathin nature, transport or tunneling of charge carriers across the templates is possible, making them ideal candidates for our purpose of investigating molecular templating in OE devices (see Focus Area D). On the other hand, we will use artificial DNA-strands for 3D templating. Molecular Building Blocks will be obtained from Focus Area A and their template deposition be investigated in Focus Area B.

B1.2 – Prof. Klaus Meerholz: Improving the anisotropy of graphene nanoribbons (GNR)

B4.2 – Prof. Stephanie Kath-Schorr: Helical Orientation of π-Systems using Xeno Nucleic Acid Template Structures

B5.2 – Prof. Annika Kurzmann: Electronic and transport properties in bilayer graphene as template for ordered molecular adsorption

In TIDE, the Focus Area C concerns the detailed study of the templated growth of MBB synthesized in Focus Area A onto the templates prepared in Focus Area B. In addition, we will use highly-oriented pyrolytic graphite (HOPG) as low-cost model for graphene. The structure and order in molecular thin films will be investigated using the synergistic set of experimental tools available from the Principle Investigators' laboratories.

C1.2 – Prof. Moritz Sokolowski: Organisation of pi-conjugated molecules in linear chains

C2.2 – Prof. Klas Lindfors: Interaction of ordered excitonic matter with metasurfaces

C3.2 – PD Selina Olthof: Controlling the electronic structure of organic semiconductors via controlled packing and growth

Focus Area D investigates charge and exciton transport in functional (pre-)devices. Optoelectronic devices are powerful analytical tools for measuring the macroscopic transport parameters in templated molecular layers. Influencing the order of molecular building blocks will allow us to obtain a further understanding of the underlying transport mechanisms and the optimization of device properties. Therefore, our focus is on investigating the impact of molecular order (amorphous vs. crystalline) on the intrinsic transport properties as well as on the eventual device functionality.

D1.2 – Prof. Paul van Loosdrecht: Ultrafast exciton and charge dynamics in ordered organic semiconductor systems

D2.2 – Prof. Klaus Meerholz: Optoelectronic Devices with polarized emission and absorption

D3.2 – Prof. Malte Gather: Templating, ordering and strong light-matter coupling for polarization control

Focus Area E addresses method development and its application to templating. Theoretical approaches play an important role for the molecular design of organic electronic devices. Considering the scope of TIDE, we have distinguished three areas. In Templating process, we start with the clean surface of the template, followed by a subsequent filling of this surface with Molecular Building Blocks. In Bulk properties, we address thin-film properties related to variations in the nano-morphology, taking into account the possible dimerization of pi-conjugated molecules, and the formation of H- or J-aggregates. In Charge carrier and energy transfer dynamics, we want to compute steady-state charge and excitonic transport as a function of the order parameter.

E1.2 – Prof. Stefan Grimme: Designing interfaces by templating: modeling epitaxially growth with a modified general force field

E2.2 – Prof. Thomas Bredow: Optical spectra and electronic structure of adsorbed pi-conjugated molecules

E3.2 – Prof. Stefan Grimme: Modelling disorder effects into ordered structures