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Jeudi 5Marsr 2015 14h
Amphi Holweck, Esc C, 1ème etage
Charge transfer and charge transport in printed electronics devices
Electronic devices printed on flexible, transparent or bio-compatible substrates would be cheap, light-weight and versatile. Printed electronics are made from solution-processed materials such as semi-conductors, oxides or metallic layers with sub-micron thicknesses. Nanostructured interfaces can be generated and form disordered donor/acceptor heterojunctions or field-effect transistors to be used as sensors, field-effect transistors or photovoltaic devices. Here, I will present three stories that explore the properties of printed electronic devices from the macroscale to the nanoscale. First, I will present our study of the degradation of organic photovoltaic devices using in situ photovoltaic characterizations, transient photocurrent measurements and time-resolved ultrafast spectroscopy. Then I will discuss which factors limit the photovoltaic performances of hybrid semiconductor nanocrystals/conjugated polymer heterojunctions using ultrafast transient absorption spectroscopy results and device analysis. Finally, I will show how ligands influences the charge relaxation dynamics in inorganic semi-conductor nanocrystals and our progress towards a systematic understanding of ligand effects thanks to ultrafast transient absorption and photoluminescence spectroscopies. These findings give rationales for further material and device engineering to improve the range, the performances and the stability of printed electronic devices.