QCM-2014-3-0030: Analysis of the ultrafast charge transfer in organic photovoltaic devices based on endohedral metallofullerenes

The proposed activity is a collaborative project between the research groups of Prof. Josep M. Poblet at the Univ. Rovira i Virgili (Tarragona) and Prof. Ángel Rubio at the Univ. del País Vasco (San Sebastián).
The main aims of project CTQ2011-29054-C02-01 "Computational modelling of compounds with interest in nanoscience and catalysis: nucleation, confinement and reactivity" (IP: Josep M. Poblet, URV), are the comprehension and rationalization of different systems related with the chemistry of nanostructures, with some fundamental properties arising from the confinement of matter, with catalysis and with surface chemistry, by means of a range of computational techniques. A first block is devoted to the study of nucleation and formation of molecular metal oxides in liquid media, also known as polyoxometalates, and to the stability of endohedral fullerenes. A second block focuses in the relationship between the confinement of water inside giant capsules and its molecular organization, in the role of cations in the formation of flexible molecular metal oxides, as well as other physicochemical properties such as the electronic localization/delocalization in reduced polyoxometalates. A third block of objectives is in line with gaining knowledge in the electronic properties of exohedral derivatives of endofullerenes with potential applications in photovoltaic devices and functionalized nanotubes. A fourth block is devoted to reactivity, split into (i) homogeneous catalysis, (ii) transition metal oxide-supported and (iii) surface phenomena. The present activity takes place within the context of the abovementioned third block, to gain knowledge in the electronic properties and charge transfer processes of molecular dyads based on functionalized endohedral metallofullerenes (EMFs). The group at the URV has contributed significantly so far to the understanding of the electronic structure and reactivity of EMFs. The group has rationalized the stabilization of M3N@C2n and established a very simple general rule based on the analysis of the orbitals of the fullerene cage that permitted us to understand and to predict the systems that are stable after a six-electron transfer from the internal metal cluster to the carbon cage (Angew. Chem. Int. Ed. 2005, 44, 7230; Chem. Commun. 2007, 4161). Additional evidences on the ionic model were afterwards confirmed combining electrochemical and theoretical studies (Angew. Chem. Int. Ed.2009, 48, 7514). The physical basis for the orbital rule defined in 2005 was later formulated in the so-called Maximum Pentagon Separation Rule, which was published in Nature Chemistry (2010, 2, 955). The group also studied the influence of the incarcerated metal in the exohedral reactivity for the Prato (Angew. Chem. Int. Ed. 2006, 45, 8176; VIP paper) and the Diels-Alder (Chem. Eur. J. 2012, 18, 8944; VIP and cover) reactions in M3N@C80, as well as the
reaction pathway for the Bingel-Hirsch cycloaddition in IPR and non-IPR fullerenes (Chem. Eur. J. 2013, 19, 5061). In collaboration with the groups of Prof. L. Echegoyen (UTEP, USA), Prof. N. Martín (Univ. Complutense, Spain), Prof. T. Torres (UAM, Spain) and Prof. D. M. Guldi (Erlangen, Germany), the synthesis, electrochemical, theoretical and photophysical studies on nitride EMFs-based dyads were performed (Chem. Eur. J. 2009, 15, 864). This activity would allow us to go a step beyond in the rationalization of the physical processes that take place in such dyads as potential
photovoltaic devices.
The project 280879-2 CRONOS CP-FP7 "CRONOS. Time dynamics and control in nanostructures for magnetic recording and energy applications" (IP: Ángel Rubio, EHU) seeks to develop a quantitative, flexible and fully atomistic theory of ultrafast dynamics in real materials. Our effort will create the necessary knowledge for advancing two technological areas crucial for the economical future of Europe and the well being of its citizens: solar energy harvesting and ultra-fast and ultra-high density magnetic data storage. In particular we will construct the necessary theoretical tools
for addressing the problems of energy photo-conversion and laser-induced ultrafast magnetization dynamics. Crucially we will not just look at how an optical excitation perturbs a materials system but also at how such an excitation can be engineered to produce a desired response. Hence both the direct and the inverse problem will be tackled. CRONOS’ theoretical program will be experimentally validated by a strong experimental activity on ultrafast pump-probe spectroscopy and industrially validated by the addition to the consortium of both a major European ICT/Healthcare multinational, Siemens, and a rapidly growing European SME, Solaronix. Equally important is the fact that the
consortium will produce a substantial amount of high-end scientific software, which will then be distributed freely to the academic community.