L’oxygène et l’eau présents dans l’atmosphère sont des acteurs important dans la dégradationdes matériaux contenus dans les dispositifs opto-électroniques organiques. Dans le but d’améliorerla stabilité et la durée de vie de ces dispositifs, ces dispositifs sont encapsulés avec desmatériaux barrière aux gaz par lamination ou par l’utilisation de couches minces. Cette dernière,notamment utilisée pour les OLED, permet de fournir des barrières aux gaz performantes parle dépôt de couches inorganiques denses directement sur les dispositifs. Cependant, elles sontassujetties aux défauts des surfaces sur lesquelles elle sont déposées.L’objectif de ces travaux est de développer une couche de planarisation afin d’homogénéiserla surface des dispositifs photovoltaïques organiques (OPV) et de réduire la rugosité dans lebut d’obtenir une protection barrières aux gaz améliorée, conférée par le dépôt subséquent decouches denses inorganiques selon divers moyens (voie liquide et gazeuse).Dans un premier temps, des couches de planarisation ont été développées à partir de 6 copolymèresp(VDF-HFP). Ces derniers ont été caractérisés afin d’améliorer nos connaissances sur cesmatériaux.Grâce à une étude de solubilité, des encres à différentes concentrations dans l’acétate d’éthyleont été réalisées. Ces dernières ont été étudiées par des mesures rhéologiques et de tension desurface permettant de mieux appréhender leur étalement, et les états de surface obtenus sur dessubstrats PET et sur les dispositifs OPV. Ces recherches ont été complétées par un contrôlede la topographie et par conséquent de la planarisation des dispositifs OPV par microscopieconfocale.Pour finir, l’étude des performances barrière des structures d’encapsulations hybrides (organiqueinorganique)ont dévoilé une bonne compatibilité lorsque la rugosité de la couche de planarisationest très faible. Ces résultats sont confirmés par des mesures barrières aux gaz et des tests devieillissement accélérés des dispositifs OPV encapsulés en enceinte climatique qui permettentd’illustrer l’intérêt de l’encre planarisante développée.Ce travail a été réalisé au laboratoire LMPO au CEA/LITEN en collaboration avec l’industrielArkema dans le but de fournir des technologies d’encapsulations performantes. / Oxygen and water present in the atmosphere are important actors of the degradation of materialscontained in optoelectronic devices. In order to increase the stability and the lifetime ofOPV, the devices are encapsulated with gas-barrier materials by lamination encapsulation orthin film encapsulation. These latter, espacially used in OLED technology, provides high performancegas barriers by depositing dense inorganic layers directly onto the devices. However,they are subject to the defects of the surfaces on which they are deposited.The purpose of this study is to develop a planarinzing layer in order to homogenize the surfaceof organic photovoltaic devices (OPV) and to reduce the roughness with the aim to obtain animproved gas barrier protection, conferred by the subsequent deposition of dense inorganic layersby various ways (liquid and gaseous routes).In a first step, the planarization layers were developed from six p(VDF-HFP) co-polymers. Thesehave been characterized to improve our knowledge on those materials.Through a solubility study, inks at different concentrations in ethyl acetate were made. Thelatter were studied by rheological measurements and surface tension to understand better theirspread, and the surface conditions obtained on PET substrates and OPV devices. Those researchswere completed with a topography control and consequently the planarization of OPVdevices by confocal microscopy.Finally, the study of the barrier performance of hybrid encapsulation structures (organic-inorganic)revealed a good compatibility when the rugosity of the planarization layer is very low. Theseresults are confirmed by permeation measurements and accelerated aging tests of OPV devicesencapsulated in climatic chambers that illustrate the interest of the planarized ink developed.This work has been performed in the LMPO Laboratory at CEA/LITEN in collaboration withthe chemical company Arkema in order to be able to provide performant encapsulation technologies.

Electronic devices made of organic molecules are starting to show their transfomative power in various fields of application today. However, as with most technologies, progress is eventually bounded by how well the inner workings of the components are understood. For electronic devices, as the name suggests, this mostly concerns the behavior of electrons or, more generally, electric charge carriers. To understand and predict device properties, knowledge of the mechanisms that govern the fate of charge carriers is indispensable. In an organic material, those mechanisms are closely related to material properties on a molecular level. Thus, the micro- and macroscale are linked in a complex manner and many questions about these links are still open. This work aims to advance the understanding of three important aspects of the field: the time-evolution of charge carrier states, the mechanism of molecular doping and the efficiency of organic solar cells and photodetectors. All three are strongly affected by a common property of organic materials: disorder. Specifcally, we extend the theoretical framework of describing the time-dependence of charge carrier motion in disordered semiconductors and use it to predict the time-dependence of recombination in organic solar cells. We find that, just as transport, recombination slows down with time, and establish a quantitative method of extracting material characteristics from the measured time-dependence of recombination. To analyze the influence of molecular doping on charge transport, we develop a computational method based on percolation theory. We show that for organic semiconductors, the popular transport energy model can not be used to predict the thermoelectric properties. The latter are important since they are often used to measure the amount of free charges introduced by doping. We are able to accurately model the activation energy of conductivity and study the important length scales and the influence of molecular parameters. Finally, we investigate the consequences of disorder on the performance of solar cells and photodetectors by studying the timescale and efficiency of the separation of photo-generated positive and negative charges. We find that, depending on the conditions, separation can in fact be either enhanced or hindered by disorder effects.

Highly responsive organic photodetectors allow a plethora of applications in fields like imaging, health, security monitoring, etc. Photomultiplication-type organic photodetectors (PM-OPDs) are a desirable option due to their internal amplification mechanism. However, for such devices, significant gain and low dark currents are often mutually excluded since large operation voltages often induce high shot noise. Here, a fully vacuum-processed PM-OPD is demonstrated using trap-assisted electron injection in BDP-OMe:C60 material system. By applying only −1 V, compared with the self-powered working condition, the responsivity is increased by one order of magnitude, resulting in an outstanding specific detectivity of ≈1013 Jones. Remarkably, the superior detectivity in the near-infrared region is stable and almost voltage-independent up to −10 V. Compared with two photovoltaic-type photodetectors, these PM-OPDs exhibit the great potential to be easily integrated with state-of-the-art readout electronics in terms of their high responsivity, fast response speed, and bias-independent specific detectivity. The employed vacuum fabrication process and the easy-to-adapt PM-OPD concept enable seamless upscaling of production, paving the way to a commercially relevant photodetector technology.