SFB 951/3: Design funktionaler molekularer Bausteine zur kovalenten und nicht-kovalenten Organisation auf Halbleiteroberflächen (TP A03)

The overarching goal of this synthesis project was and is the creation of high quality, functional HIOS with
unique characteristics that - in part - are governed by the structures of the custom-designed molecular building
blocks. During the current funding period, we synthesized a variety of molecular building blocks to prepare
structurally and compositionally well-defined HIOS. In particular, we were able to develop routes to conjugated
organic molecules with defined inherent molecular properties, such as optical gap and oxidation/reduction
potentials, and utilized the introduction of dipoles as well as of anchoring groups to direct their assembly,
primarily on ZnO surfaces, using physisorption and chemisorption, respectively. Furthermore, photoswitchable
molecules that undergo large changes in their dipole moments as well as frontier molecular orbital levels were
developed and incorporated into HIOS and related opto-electronic and plasmonic functional structures and
devices. In the upcoming funding period, we aim at combining optimized photoswitchable molecules with twodimensional
semiconductors, primarily monolayers of transition metal dichalcogenides (TMDCs) to create new
hybrid functionalities and devices.
First Subproject “Photoswitchable Molecules”: A variety of photoswitchable molecules, most notably dihydropyrenes,
will be developed to exhibit maximum dipole changes as well as HOMO/LUMO level changes,
and also to allow for convenient optical switching. Special attention will be given to tune excitation wavelengths,
quantum yields, thermal half-life, and fatigue resistance in order to maximize the performance of these molecular
HIOS building blocks.
Second Subproject “Surface Attachment”: New routes to covalently assemble conjugated organic molecules,
and in particular the optimized photoswitchable molecules, to TMDCs will be developed. Key will be the design
of suitable linking moieties, which allow to attach the photoswitches in a specific orientation, in particular to
Project A3 (Hecht)
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orient their dipole moments and thus maximize their Coulomb interactions with the TMDCs upon light-triggered
switching.
These directions will be followed in collaboration with A8 (N. Koch), A12 (C. Koch), and A14 (Franke), concerning
the structural and electronic characterization of the prepared HIOS. Insights into resulting specific
HIOS elemental functions, such as hybrid excitations and their dynamics, will be gained together with
B3 (Blumstengel), B7 (Neher), B9 (Stähler), B15 (Bolotin) and B17 (Ernstorfer/Wolf). Feedback from theory
will further aid our understanding of molecular and surface chemistry and their interaction to translate molecular
switching events to overall HIOS property changes. Based on these insights, prototypical HIOS devices
will be fabricated with B14 (List-Kratochvil) and B7 (Neher).

Projektleitung
Hecht, Stefan Prof. (Details) (Organische Chemie und Funktionale Materialien)

Mittelgeber
DFG: Sonderforschungsbereich

Laufzeit
Projektstart: 07/2019
Projektende: 06/2023

Zuletzt aktualisiert 2020-01-06 um 20:07