Research Area B
Complex Hybrid Nanostructures Assemblied in Different Dimensionalities and in Ordered Matrices
The focus of this research area is on the transformation of the material properties of isolated anisotropic nanohybrid structures into macroscopic systems in order to demonstrate the bridging to potential applications. From the multitude of applications in the technological field, three different strategies are pursued here as examples. The first sub-area focuses on gas sensor technology, for which lateral 2D assemblates of the individual components are generated in order to investigate electrical transport in the presence of different gases. In the second area, switchable materials are investigated in which organic polymer structures are used as functional matrices in order to vary the distance and arrangement of the nanostructures. In the third area, monolithic materials with anisotropic optical properties are generated, in which the 3D arrangement is carried out via dimensionally stable, functional inorganic matrices.
Oriented Metal-Semiconductor Assemblies
Oriented metal-semiconductor assemblies are to be linked to 2D networks whose current transport characteristics are to be used for chemical sensors. Based on findnings on the optical and electrical properties of single, elongated metal-semiconductor hybrid structures, 2D structures are initially generated by interparticle interaction or via defined molecular bridges. After applying microscopic electrodes, the (photo-)current will be examined in the presence of certain analytes for the purposes of chemical sensor technology. In conjunction with quantum mechanical model calculations, the effect of chemical influences on the electrical transport through complex nanostructures will be understood in detail.
Oriented Nanostructures in Polymer Matrices
Oriented nanostructures in polymer matrices should lead to macroscopic directed effects. The alignment of the anisotropic, nanoscopic structural elements in three dimensions should be done either by external stimuli such as shear forces or by inherent structure-directing elements of the polymers, such as self-assembling polymer blocks. For example, poly (N-isopropylacrylamide) (PNIPAM) or copolymers and block copolymers are to be used here as stimuli-responsive polymer networks. After the oriented embedding of the anisotropic metal/semiconductor particles, the distance between the particles should be continuously varied as a function of external stimuli such as temperature, pH value, or salt concentration.
Hybrid Nanostructures in Inorganic Matrices
Hybrid nanostructures in inorganic matrices are to be produced either by forming the matrix around preformed nanostructures by sol-gel chemistry or by generating nanostructures within pre-defined matrices, in particular defined pores. Thus, for example, semiconductor-DRs from Research Area A are to be coated with surfactants/lipids to produce water-soluble anisotropic micelles. On the basis of soluble silanes, controlled sol-gel approaches are to be developed that allow self-assembly of the particles into ordered superstructured layers. This results in superstructures of oriented nanoparticles within inorganic (e.g., SiO2, TiO2, InxSn1-xO2) and organic-inorganic (e.g. organosilicate) matrices in the form of thin films.