Final Report Summary - MARCHES (Modelling of Architectures Ruled by Coupled or Heightened Excited States)
The MARCHES project aimed at design multi-photochromic compounds with tailored properties using theoretical chemistry tools. Photochromes are molecules existing in two different forms, the inter-conversion between the two being controlled by light. If the two forms are significantly different, photochromes can be used to store information (0/1). Molecules including several switchable units are potentially able to store and process more complex logical information than isolated photochrome. Indeed, a coupled trimer could, in principle, store a byte rather than a bit of data, paving the way towards more complex and efficient devices. Nevertheless, the practical applications of coupled molecular photochromic entities have been limited by a series of hurdles. During the MARCHES project, we used first-principle approaches to explore several paths allowing to obtained improved multi-photochromes, including, changing the linker, adding chemical substituents and using semi-conducting or metallic surfaces. In the course of the project, several schemes and protocols useful for other applications, e.g. a) the calculation of absorption and emission spectra with improved accuracy; b) the modeling of excited-state proton transfer allowing to obtain white-light emission; c) the optimizations of dyes for solar cells, have also been developed.