Switchable fluorescence hysteresis by light – SWIST

In the field of smart materials, photoswitchable multichromophoric systems are prone to show fluorescence hysteresis effects, unexplored to date. The SWIST project proposes to design well-structured molecular architectures composed of a large number of fluorescent and photochromic units linked to a cyclodextrin platform, allowing energy transfer processes. Several multichromophoric molecular architectures of increasing complexity will be designed, with a strategy based on a convergent click-chemistry method. The competitive photoisomerization kinetics of the different photoactive units are expected to drive the system to different reaction pathways when illuminated by UV or visible light, leading to a fluorescence hysteresis cycle. A multidisciplinary approach, based on complementary scientific partners, combining molecular design, synthetic chemistry, spectroscopy and theoretical modeling, is expected to tackle this challenging topic. Such a hysteresis behavior originates from collective effects and interactions between molecular subunits. It is of great fundamental interest, but also promising for the development of a wide variety of high-technology devices.