A radical approach to new organic light-harvesting materials – RADPOLIMER

This project unites cutting-edge advances in spectroscopy, chemistry and simulation to engineer and directly visualise the electronic photodynamics of a new class of organic light harvesting materials with applications in future photovoltaics, LEDs and devices for the implementation of condensed matter quantum information (QI) protocols. Topochemical polydiacetylenes quantum wires (PDAs) that are at the core of the project combine exceptional quantum optoelectronics properties like disorder-free 1D conjugation, conformational diversity and strongly delocalised excitons (with low temperature coherent photon emission). Their novel functionalization based on the implantation of free stable radicals associated to their nanoarchitecturing in model, geometry-controllable, tubular structures opens promising yet unexplored perspectives in the fields of organic spintronics and magneto-optoelectronics. In our new PDAs enhanced and tunable spin interactions will indeed be promoted and exploited to address multiple issues among which (i) the manipulation (using ‘all-optical’ techniques), separation (through singlet fission and/or the active application of nanoscopic magnetic forces) and stabilization of spin entangled, triplet excitons pairs; (ii) the concerted exploration of the magneto-optical effects arising from collective excitations and ordering of the radical arrays supported by the rectilinear polymer template; (iii) the extraction of general organization principles for the design of enhanced performances conjugated systems incorporating radical centers. To reach its goals the project will develop along two axes. One the one hand, state-of-the-art spectroscopies capable of resolving broadband, femtosecond exciton dynamics on nm length scales - potentially in single PDA wires - will be realized: micro-photoluminescence and transient absorption micro-spectroscopy will be privileged. On the other hand, an exhaustive theoretical modelling of the radical-PDAs interaction and their spatio-temporal optoelectronic properties (absorption spectra, geometries, excited states – energy transfer, spin decoherence – dynamics, magneto-optical response to external fields and gradients etc) will be carried out. Both approaches will together provide an unprecedented microscopic view of how photons, excitons, spins, vibrations - and potentially magnetism - interact and might be manipulated in organic energy and QI applications.