MOEBIUS · Multifunctional Organic-inorganic Elements with Biosensing re-Usability

Multifunctional Organic-inorganic Elements with Biosensing re-Usability

In the first phase of MOEBIUS project the porphyrin and fullerene derivatives were self-assembled on the SnO2 (110) and ZnO (1010) sensing surfaces and embedded into the nano-channels of the ion-track membranes. Materials development has been supported by morphological and physico-chemical characterisation techniques like optical, fluorescence lifetime microscopy and time resolved spectroscopy. Besides, the theoretical aspects of the ultrafast electron transfer (ET) in hybrid nanoscale interfaces have been developed. It was found that the donor-acceptor pair molecules are tilted down to the surface with angle of 35 - 40o. At the same time, the porphyrin LUMO band widens up, indicating on coupling between the self-assembled organic film and metal oxide conduction bands. The electron transfer does not occur through the links that stabilise molecular adsorbates on the electrode, but rather by the tunneling through the space between the tilted organic cores and semiconductor oxide surface. The destabilisation of the surface orbitals in dependence of the tilt angle has a direct impact on the ET from pi-orbitals of the dyads to the surface metal ions. The obtained results are of fundamental importance for the creation of selective hybrid sensors as well as solar cells based on organic-modified oxide electrodes. The stability of the organic compounds on pure and doped SnO2 (110) and ZnO (1010) surfaces has been investigated using first principles density functional theory (DFT) calculations. The weakest point of the carboxyl or silane linkers with respect to its stability is the bond between the chemisorbed oxygen and the surface metal atom. It is indicative that this particularly bond is mainly affected by the introducing of dopant. Thus, the appropriate surface pattering and/or doping have been proved as a promising technological steps in grafting procedures and engineering of the biosensor prototypes. The nature of intrinsic magnetism in tin dioxide material has been first worldwide identified. The electron paramagnetic resonance signals consistent with experimental observations were found for tin vacancy and its complex with oxygen vacancy doped with hydrogen or fluorine, which points out that tin vacancies may be present in SnO2 at essentially higher concentration than it is predicted by DFT based on the formation energies calculations. The obtained results have a positive impact on the explanation of the high-temperature ferromagnetism observed in oxide nanowires and will be used for creation of the magnetic biosensor prototypes based on the developed ion-track nanostructures. The collabouration between the research groups will be continued in the frame of reintegration phase of the MOEBIUS project. The important aspect of the further activities will be exploring of the market and business opportunities of the developed sensor prototypes for people health and safety protection together with established industrial partner - Harmotech, GmbH.

Текст от CORDIS, на английски · Данни: CORDIS, © Европейски съюз