|
Self-assembled structures are currently of great interest for nanochemistry and chemical nanotechnology. Aerogels consisting of nanoparticles combine promising advantages like high porosity, low density and huge internal surface, whilst retaining the unique properties of their building blocks like quantum-confined optics and catalytic behavior. Following the recent success in fabrication of new types of aerogels from semiconductor[1] and noble metal nanocrystals,[2] we demonstrate the water-based formation of mixed aerogels consisting of strong emitting, thiol-capped CdTe nanoparticles and thiol-functionalized gold seeds. The formation is carried out by photochemical treatment and supercritical drying resulting in homogeneous and voluminous monoliths. The composition and topography of the gel was examined by SEM/EDX and TEM proving the highly porous architecture and the control of particle ratios in the network through the initial colloid mixtures. Optical behavior was studied by diffuse reflection and fluorescence spectroscopy verifying the retained optical properties. With increasing metal ratio the fluorescence intensity is decreased due to the quenching of the metallic system on the fluorescence process. By carrying out lifetime measurements of the produced gels this effect was examined. Porosity measurements by nitrogen adsorption characterized the highly porous gel network with specific internal surfaces of 170 m2/g which is in good accordance to porosity values of such structures found earlier. The formation of those gels provides a controllable method to produce highly porous hybrid materials of special interest for applications in nanoplasmonic devices and photocatalysis. [1] N. Gaponik, A. Eychmüller et al., Adv. Mater. 2008, 20, 4257 [2] N. C. Bigall, A. Eychmüller et al., Angew. Chem. Int. Ed. 2009, 48, 9731 |
|