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.