3D nanoparticle assemblies offer a unique platform to enhance and extend
the functionality and optical/electrical properties of individual nanoparticles.
Especially, a self-supported, voluminous, and porous macroscopic material built
up from interconnected semiconductor nanoparticles provides new possibilities
in the field of sensing, optoelectronics, and photovoltaics. Herein, a method is
demonstrated for assembling semiconductor nanoparticle systems containing
building blocks possessing different composition, size, shape, and surface
ligands. The method is based on the controlled destabilization of the particles
triggered by trivalent cations (Y3+, Yb3+, and Al3+). The effect of the cations is
investigated via X-ray photoelectron spectroscopy. The macroscopic, self-supported
aerogels consist of the hyperbranched network of interconnected CdSe/
CdS dot-in-rods, or CdSe/CdS as well as CdSe/CdTe core-crown nanoplatelets is
used to demonstrate the versatility of the procedure. The non-oxidative assembly
method takes place at room temperature without thermal activation in several
hours and preserves the shape and the fluorescence of the building blocks. The
assembled nanoparticle network provides longer exciton lifetimes with retained
photoluminescence quantum yields, that make these nanostructured materials
a perfect platform for novel multifunctional 3D networks in sensing. Various sets
of photoelectrochemical measurements on the interconnected semiconductor
nanorod structures also reveal the enhanced charge carrier separation.
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