Welcome to Thin Organic Films
The control of the microscopic structure of organic materials on the micro- to nanometer scale can be achieved by cooperative and self-organization effects as also applied in biological systems. Organizing organic molecules into ordered structures can be achieved by the well known Langmuir-Blodgett (LB) technique as well as a the subtle self-assembly (SA) technique usually involving chemical bonds with the substrate. We are particularly interested in the possibility to construct monolayers system with controlled lateral structures, which can be realized by adjusting the balance of the different phases within the films (with one or more chemical components) thermodynamically and kinetically. The ordered molecules with active end groups can be further used for the specific adsorption of molecules, proteins and nanoparticles.
Scanning probe microscopy (SPM) became a powerful tool to characterize monofilms on the air/solid substrate interfaces. By applying SPM methods, we do not only obtain the information in topography and structure, but also measure the mechanical and electrostatic properties. In addition, scanning force microscopy (SFM) can be used to create local nanostructures in thin organic films.
The Thin Organic Films research group consists of the following coworkers:
Prof. Dr. Lifeng Chi
Dr. Jörn-Holger Franke
Dr. Yuekun Lai
Dr. Liqiang Li
Dr. Wenchong Wang
Dr. Haiming Zhang
Dr. Dingyong Zhong
Chuan Du
Yueyue Chen
Carsten Hentschel
Yong Li
Fei Pan
Zhenkui Shen
Hong Wang
Congyun Zhang
Research profile:
1. Surface (nano)patterning via self-organization/self-assembly The concepts of self-assembly and self-organization provide interesting routes towards surface patterning (from a few nanometers to micrometer in size) via bottom-up approaches. We are particularly interested here in the possibilities to construct monolayers system with controlled lateral structures, which can be realized by adjusting the balance of the different phases (with one or more chemical components) thermodynamically and kinetically by means of Langmuir Blodgett (LB) technique. The goal is the development of new surface patterning methods based on dynamic self-assembly.
2. Molecular interactions with structured surfaces Template directed self-assembly of nanomaterials and molecular complexes into functional systems can be realized by using hetergenous patterned surfaces. The hetergenous surface structures may be composed of different tailored molecules, but can also be composed of single component but with different molecular packing. We are interested in the mechanisms of molecular intereactions - from liquid phase or gas phase - with such structured surfaces. Specific (e.g. chemical binding) and unspecific (e.g. electrostatic force) interactions need to be taken into consideration, together with molecular diffusion and nucleation.
3. Connection of nanoscopic materials with microscopic structures Connection of functional molecular complexes and nanomaterials with addressable microscopic structures is an important issue for applications in e.g. nanoelectronics. We started in the last two years to combine surface modification with SAMs, e-beam lithography, soft-lithography and template directed self-assembly to connecting nanoclusters, functional molecules or molecular aggregates with addressable micro-electrodes. The functionality of the systems can be proved by electrical or optical measurement.
4. STM/SFM on molecular assemblies Scanning probe microscopes (SPMs) became powerful tool to characterize molecular assemblies on different surfaces. Among these tools scanning force microscopes (SFM) in dynamic mode allow us to investigate soft molecular assemblies without mechanical damage. On the other side, using scannig tunneling microscopy (STM) we reveal molecular packing with high spacial resolution in monolayer and multilayer systems prepared under ambient conditions as well as in ultrahigh vacuum (UHV).
Pattern formation during LB transfer. By adjusting experimental parameters, different patterns with controllabe size features (down to 100 nm) can be formed.
