Ultrafast@LENS

Welcome to the webpage of the

ULTRAFAST SPECTROSCOPY GROUP

Time resolved spectroscopic methods allow to follow the evolution of the excited states of molecules or materials upon photoexcitation. We use a variety of experimental techniques such as pump-probe or 2D spectroscopies both in the visible and infrared spectral ranges to gather informations on the electronic and structural relaxation processes occurring in the molecular systems under investigation.

Our research interests are mainly focused on the development and the application of non-linear spectroscopic techniques and cover the different research topics. Look here for more informations.

Research topics

Innovative Molecular Photoswitches

Molecules which respond to a light stimulus with a change of their structure find application in various fields, allowing for the prodution of 'smart' materials with controllable optomechanic or optoelectronic properties. Using time-resolved spectroscopy, our research in this field is focussed on the understanding of the timescale and mechanisms of the light-induced transformations occurring in such systems. A clear understanding of the photoswitching mechanisms is indeed a key step to engineer new and improved molecules for tailor made applications. More details can be found here.

Metal-Free Triplet Photosensitizers

Efficient production of long-lived triplet states in molecular systems can be advantageus for several optical and biomedical applications. As an example, systems able to emit delayed fluorescence as the result of triplet-singlet inverse intersystem crossing can be used for the fabrication of OLEDs. In the medical field, triplet states of molecules can efficiently react with molecular oxygen to produce reactive oxygen species (ROS) able to kill cancer cells, an approach named "Photodynamic Therapy" (PTD). Heavy-atom effect induced by metals such as Br, I, Pt, Ru, Ir is a key strategy to enhance the yield of Intersystem crossing (ISC) in photosensitizers, but it also shortens their triplet excited-state lifetime. Furthermore, the presence of these elements is highly undesirable due to their toxicity and high costs. Using ultrafast time-resolved spectroscopy, we investigate the mechanisms for efficient triplet formation in multichromoforic systems with the aim of providing design principles for cheap, metal-free improved triplet photosensitizers. Look here for more details.

Materials for Energy

The development of new dyes with superior spectroscopic properties is crucial for increasing the efficiency of dye-sensitized solar cells and solar concentrator units. In close collaboration with synthetic and theoretical chemists we aim at understanding the structure-function relationships enabling to go a step forward into the realization of improved photovoltaic devices. More details here.