Mamatimin ABBAS soutiendra son HDR, mercredi 5 mai 2021 à 14H, sur le sujet suivant : "Organic Electronic Devices: from Deposition Technique to Advanced Interface Engineering".

Cette soutenance se tiendra en anglais et sera accessible en visioconférence via zoom: https://u-bordeaux-fr.zoom.us/j/87365178693?pwd=NVdFc2t2RTQrb1AzT1NkSnhWMHBaZz09

Abstract

Organic semiconductors are emerging as a formidable force to change the electronics landscape. Flexible, lightweight, large-area organic semiconductor devices find their applications as light sources, solar cells, photodetectors, and sensors, to name a few. The overall performance of these devices relies heavily on manufacturing processes and interface engineering in addition to their intrinsic physicochemical properties. This document demonstrates our efforts over the past decade to address a number of issues relating to solar cells and organic field-effect transistors, as well as hybrid organic / inorganic light-emitting transistors. Our journey began with the study of a biopolymer-melanin, a material notoriously difficult to deposit due to its very low solubility, for which we have developed the electro-spray deposition technique. We also applied this technique to pi-conjugated polymers and have been able to produce, thanks to this deposition technique, polymeric solar cells with three layers. We have shown that improving the performance of organic solar cells requires a balance of electron and hole mobility. For this study, we developed a water-soluble polymer dielectric with low trap densities to study the mobility of both charge carriers by organic field effect transistors (OFET) technique. We have also used flexible high performance OFETs to amplify the signal of microelectromechanical systems. This monolithic integration has greatly improved the sensitivity of these pressure sensors. The lack of stable, n-channel, high mobility organic semiconductors has led us to explore solution processed metal oxide thin-film transistors. The combination of p-type organic semiconductors and n-type metal oxides has enabled us to optimize hybrid light-emitting transistors. This original approach has considerably reduced the turn on voltage and the efficiency of electroluminescent transistors. Finally, a suitable hole injection layer and a high permittivity dielectric allowed us to achieve an operating voltage of only 5V. All these studies underline the crucial importance of the engineering of interfaces in organic electronics.