© Fraunhofer IAP
© Fraunhofer IAP

Functional Materials and Devices

Nanomaterials and quantum dots

 

Quantum dots (QDs) are a new class of nanomaterials, in which the absorption and emission properties can be set in a unique way. We explore new methods to produce conventional cadmium-based core-shell semiconductor nanoparticles up to the gram scale. We also develop cadmium-free syntheses to provide environmentally friendly indium phosphide-based QD for light emitting diodes (LEDs), organic light emitting diodes (OLED) and for solar technology.

 

Nanomaterials

Nanoparticles offer multiple perspectives for the increasing complexity of technical applications and their miniaturization. They are already being successfully used as luminophores, electrical circuit elements, magnetic fluids for finishing material surfaces or in sensors. Producing high-quality nanoparticles requires technical know-how with respect to various factors such as the choice of ligands for passivation and functionalization of the particle surface, the colloidal properties and a suitable separation of the particles and their cleaning. We are able to produce stable gold and silver nanoparticles as well as manganese-doped zinc sulfide nanoparticles (ZnS: Mn) or europium-doped yttrium vanadium oxide nanoparticles (YVO4:Eu) with a high quantum yield for various applications on a gram scale. Furthermore it is possible to stabilize particles by SiO2 encapsulation.

 

Quantum Dots

Quantum dots are a new class of materials, in which absorption- and emission properties can be set by adjusting particle size and particle surface passivation by means of various ligands. Almost the entire spectral range is accessible through targeted synthesis. These unique properties allow its use in various application areas, such as luminophores in display technology, for up-conversion in photovoltaics or as security features on banknotes. The functionalization of the particle surface makes the use of QDs in analytics and bioanalysis as well as in therapeutic applications attractive. We are testing new methods to produce conventional CdSe QDs, CdSe/ZnS core-shell QDs and IR-active PbS QDs in the gram scale. In addition we design Cd-free syntheses to provide environmentally friendly InP/ZnS QDs for LED/OLED- and display technology as well as IR-active CuInS2 QDs for an increasing efficiency in solar cells.