Optical properties of NIR photoluminescent PbS nanocrystal-based three-dimensional networks.

The assembly of nanocrystals (NCs) into three-dimensional network structures is a recently established strategy to produce macroscopic materials with nanoscopic properties. These networks can be formed by the controlled destabilization of NC colloids and subsequent supercritical drying to obtain NC-based aerogels. Even though this strategy has been used for many different semiconductor NCs, the emission of NC-based aerogels is limited to the ultraviolet and visible and no near-infrared (NIR) emitting NC-based aerogels have been investigated in literature until now.

Investigation of the Photocatalytic Hydrogen Production of Semiconductor Nanocrystal-Based Hydrogels.

Destabilization of a ligand-stabilized semiconductor nanocrystal solution with an oxidizing agent can lead to a macroscopic highly porous self-supporting nanocrystal network entitled hydrogel, with good accessibility to the surface. The previously reported charge carrier delocalization beyond a single nanocrystal building block in such gels can extend the charge carrier mobility and make a photocatalytic reaction more probable. The synthesis of ligand-stabilized nanocrystals with specific physicochemical properties is possible, thanks to the advances in colloid chemistry made in the last decades.

Temperature-Sensitive Localized Surface Plasmon Resonance of α-NiS Nanoparticles.

The presented work shows a synthesis route to obtain nanoparticles of the hexagonal α-NiS phase and core-shell particles where the same material is grown onto previously prepared Au seeds. In the bulk, this nickel sulfide phase is known to exhibit a metal-insulator type phase transition (MIT) at 265 K which drastically alters its electrical conductivity. Since the produced nanoparticles show a localized surface plasmon resonance (LSPR) in the visible range of the electromagnetic spectrum, the development of their optical properties depending on the temperature is investigated.