Selective binding of dye molecules and CdSe nanocrystals on nanostructures generated by AFM lithography of silicon surfaces

Abstract

Anchoring optically active molecules or semiconductor nanocrystals on nanostructured surfaces is one of the first steps for building complex structures with variable properties and functions. Electrostatic interactions have been used for selective binding of cationic molecular species on lithographically generated and negatively charged nanostructures. Semiconductor nanocrystals, covered by amphiphilic molecules, have been bound via hydrophobic interactions. Selective binding of cationic Rhodamin 6G molecules to freshly prepared silicon oxide nanostructures as well as the CdSe/ZnS nanocrystals to the surrounding hydrophobic alkyl monolayer could be identified both by optical methods and by atomic force microscopy. The adsorption of CdSe/ZnS nanoparticles was accompanied by self-organization phenomena of the surfactant tri octyl phosphine oxide (TOPO).

Iron pyrite nanocrystal film serves as a copper-free back contact for polycrystalline CdTe thin film solar cells

“…During the synthesis of these NCs, TOPO controls the growth rate, influences the size and shape of the NCs, and caps the NC surface. The ~2 nm length of the TOPO molecules sheathe the NCs and maintain isolation between neighboring NCs within the film [63]. Cube-shaped FeS 2 NCs capped with TOPO molecules are displayed in Fig.…”

Optical detection of heterogeneous single molecule diffusion in thin liquid crystal films

“…The hydrodynamic model completely neglects specific interactions of the reporter molecules with the interface. However, from previous experiments we know 22,37,42 that dye molecules partly stick to the surface, e.g. via chemical (hydrogen) bonds to silanol groups, 16 which are to a certain extent always present at SiO 2 interfaces.…”

Spectral shift of cresyl violet luminescence on charged silicon oxide nanostructures

“…The remaining challenge, however, is to find adequate routes for giving these structures a desired functionality. Our method to generate functional nanostructures on alkyl‐passivated silicon is a combination of a top–down structuring via atomic force microscope (AFM)‐induced local anodic oxidation (LAO) and a bottom‐up self‐assembly of cationic dye molecules on the structure by electrostatic interactions .…”