CRC TRR 61 B07 - Characterization of functional organic thin films by high resolution atomic force microscopy

Basic data for this project

Description

In project B7, we will investigate functional organic layers by dynamic force microscopy and spectroscopy(nc-AFM) under ultrahigh vacuum (UHV) conditions and temperatures variable between 5-300K (LT-nc-AFM) in continuation of the work done in the first funding phase of TRR 61. In the second funding period, a central goal of the nc-AFM investigation is to understand the origin of the submolecular contrast observed in molecular layers and to study the influence of metallic clusters or molecular moieties attached to the probing tip to the observed contrast. Using dynamic force spectroscopy in the constant amplitude mode, 3-dimensional force mapping will be applied, which provides quantitative information of the interaction between the tip and a sample with picometer and nanonewton resolution. Besides submolecular structures, this allows us also to study the influence of intermolecular bonding states and substrate-molecule interactions on homo- and hetero-organic layers, where the latter refers to both, heterogeneity within a single layer and between layers. Thesubstrate-molecule interaction will be studied by choosing different inorganic substrates. These investigations include experiments where we will utilize the temperature dependence of the substrate conductivity and its effect on the charge transfer to the molecular layers. The sample systems are prepared under UHV conditions by molecular beam deposition. Our microscopic investigations will be complemented by photoelectron spectroscopy (PES) and low energy electron diffraction (LEED). The results will be of high value for the basic understanding of force interactions between different molecules and the properties of substrate-molecule interfaces, which are highly relevant for the molecular self-assembly in organic optoelectronic systems.