Final Report Summary - LILO (Light-In, Light-Out: Chemistry for sustainable energy technologies)
The project LiLo was concerned with the development of new and sustainable methods for the conversion of photons to stored electrical energy (Light-In) and the conversion of stored electrical energy to light (Light-Out). The Light-In approach was predicated upon Dye Sensitised Solar Cells (DSCs) which modify the response of a wide band gap semiconductor by appending a coloured material which absorbs in the visible region of the spectrum to its surface. The major thrust of the Light-In component of LiLo was to replace current state-of-the-art dyes for DSCs which are usuallyy ruthenium complexes by those containing Earth abundant metals such as copper or zinc. This objective has been achieved, although the efficiencies to date are still lower than those of the ruthenium dyes. Important discoveries have been the development of sequential on-surface functionalization technologies ("Surfaces as ligands, surfaces as complexes") and the consequent realisation of device regeneration strategies. The Light-Out part of LiLo has concentrated upon the optimisation of materials for use as electroluminophores in Light Emitting Electrochemical Cells (LECs). Two major areas have been addressed (i) the optimisation of iridium-based materials for devices with colour output across the visible spectrum (red, orange, green and blue emitting materials have been particularly studied) and (ii) the development of copper-based materials for use in LECs. The project achieved significant success in both of these areas and brings copper-based materials for LECs close to commercial viability. In parallel to these scientific targets, LiLo has developed new methods and standards for the evaluation and validation of DSC and LEC devices.