Metal-Free Triplet Photosensitizers for optical and PTD applications

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 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). A crucial mechanism of energy transfer within triplet Photosensitizers is Intersystem crossing (ISC), whose yield can be enhanced through various strategies, including heavy atom effect (Br, I, Pt, Ru, Ir). However, the presence of such metals is highly undesirable due to their toxycity, their high costs and to the shortening of triplet excited state lifetime induced by the heavy atom effect.

Using 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.

Read more on:

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