ICS Award Lecture
Colloidal quantum materials: From basic science to applications

Colloidal quantum materials, also known as semiconductor nanocrystals, manifest fascinating size, composition and shape dependent optical and electronic properties related to quantum confinment effects. A first aspect of design and functionality of these quantum materials aims at electron-hole recombination yielding highly emissive quantum dots and rods. Design and control of the particle structure especially by core/shell type hetero-structuring are required to achieve maximal fluorescence quantum yield and stability, with relevance for a wide range of technological applications. In this context we will discuss various synthesis routes for shape controlled semiconductor nanorods and report on the shell growth in the thermodynamic limit achieved by reduced reactivity of the shell precursors. The relevance of the shell growth to the optoelectronic properties will be discussed and applications of semiconductor nanocrystals and nanorods in displays will be presented.

A second aspect aims to construct photocatlaytic nanoparticles manifesting electron-hole charge separation that may be utilized for photocatalytic redox reactions. This is realized in hybrid semiconductor-metal nanoparticles pioneered by us in 2004 by forming metal tipped semiconductor nanorods. The synergistic optical and chemical properties of such hybrid nanoparticles resulting in light-induced charge separation and charge transfer, allow photocatalytic activity which can promote redox reactions, and open a pathway for converting solar energy to chemical energy stored in a fuel. An additional aspect concerns the use of the hybrid nanoparticles in generation of reactive oxygen species and its application in photopolymerization and 3D printing as a new type of photo-initiators, for light-controlled enzymatic activity, and in additional biomedical and environmental aspects.