Institut des
NanoSciences de Paris
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Soutenance de thèse de Xiao Liu - Vendredi 13 novembre 2020 à 9 h 30

Xiao Liu, doctorante dans l’équipe Physico-chimie et dynamiques des surfaces soutient sa thèse le vendredi 13 novembre 2020 à 9 h 30.

Sorbonne Université - 4 place Jussieu - 75252 PARIS Cedex 05 - Atrium (- 1, RC27)

Elaboration and Characterization of Organic Semiconducting Thin films for Optoelectronics

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Figure a) Molecular structures of organic semiconducting materials and Schematic representations of organic field effect transistors (OFETs) with these semiconducting materials as the active layers. b) Molecular structure of an organic fluorescent material and Schematic representation of organic light emitting diode (OLED) with this fluorescent material as the emitting layer.

Abstract

In 1977, the high conductivity of conducting polymer Polyacetylene was reported by Heeger, MacDiarmid, Shirakawa et al., and they were awarded the Nobel Prize in Chemistry in 2000 for their revolutionary discovery that plastic can, after certain modifications, be made electrically conductive. Their findings yielded remarkable interest of organic semiconductors (OSCs) in both basic scientific research and industrial application in organic optoelectronics such as organic photovoltaic (OPV), organic field-effect transistor (OFET), and organic light emitting diode (OLED). Compared with their widely known inorganic counterparts (mainly silicon, germanium, and metal oxide semiconductors), OSCs offer some intrinsic advantages. Firstly, they are solution-processible on lightweight, very-low-cost and large-area substrates such as glass, plastic or metal foils which can be used under low processing temperature. Secondly, the mechanical flexibility of organic materials opens the door to flexible, foldable and stretchable organic electronics including flexible OLED displays, flexible batteries, electronic circuits fabricated in clothing and biomedical devices. However, there is a big challenge. These devices performances depend significantly on the molecular packing motifs, crystal structures and morphological defects which could be tuned and optimized by carefully choosing deposition methods (solution-processing methods or solution-free methods). Therefore, in this PhD project, we have studied how to optimize the fabrication methods of semiconducting thin films based on different π-conjugated molecules in order to figure out the structure/property relationships and maximize the performances of the corresponding optoelectronic devices (OFETs or OLEDs). This work confirms the importance of the morphology optimization of semiconducting active layers in the field of the optoelectronics to achieve high charge transport or photophysical properties.

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  • M. Nicolas BATTAGLINI - Maître de conférence HDR - ITODYS, Université de Paris - Rapporteur
  • M. Guillaume WANTZ - Maître de conférence HDR - MS, Université de Bordeaux - Rapporteur
  • Mme Agnès MAITRE - Professeure - INSP, Sorbonne Université - Examinatrice
  • M.Thomas HEISER - Professeur - ICube, Université de Strasbourg - Examinateur
  • M. David KREHER Professeur - ILV, Paris-Saclay Université - Invité
  • Mme Emmanuelle LACAZE - Directrice de Recherche - INSP, Sorbonne Université - Directrice de thèse
  • M. Fabrice MATHEVET - Chargé de Recherche CNRS - IPCM, Sorbonne Université - Co-Encadrant