Afin de limiter son impact environnemental, un dispositif photovoltaïque doit être performant, durable dans le temps et fabriqué avec un procédé peu énergivore. Depuis 2 décennies les cellules photovoltaïques organiques ont vu leurs rendements se décupler (14 % atteint en 2018) les rendant de plus en plus compétitives avec les technologies dominant le marché.Les dispositifs organiques commerciaux sont généralement produits par impression réalisée à l’air ambiant et possèdent donc des coûts de fabrication relativement faibles. La durée de vie de ces systèmes variera selon les matériaux mis en jeux et selon l’environnement d’utilisation et reste un point faible de la technologie . Un nombre important de groupes présentent des études de durée de vie sur des dispositifs de petites surfaces et dont le procédé de fabrication n’est pas au stade industriel. Le travail présenté dans ce manuscrit a été mené en collaboration avec ARMOR et le CEA-INES et a pour but de présenter l’application de méthodes de caractérisations et d’analyses non destructives, permettant d’expliquer l’évolution sous illumination des modules photovoltaïques organiques (OPV) produits au déroulé sur ligne pilote. Nous présenterons le développement et l’utilisation de méthodes d’imagerie (électroluminescence, photoluminescence), de caractérisations I(V) sous illumination variable et de modélisation, permettant de comprendre les différences observées sur les performances après fabrication et après vieillissement. Un comparatif entre des cellules et des modules OPV sera également établi. Ce travail a ainsi permis de mettre en évidence les disparités existantes au sein de modules issus d’un même procédé de fabrication. De plus, certaines causes de dégradation de ces modules sous illumination ont été identifiées et des solutions sont proposées pour y remédier. / In order to limit its environmental impact, a photovoltaic device must be efficient, sustainable and manufactured with a process that consumes low energy. In the last two decades organic photovoltaic cells have seen their efficiency increase tenfold (14% reached in 2018) making them more and more competitive with market-leading technologies (Si, thin films).Commercial organic devices are generally produced by printing in ambient air and therefore have relatively low manufacturing costs. The lifespan of these systems will vary with the materials involved and the applied stress and remains a weak point of the technology . A large number of research groups present lifetime studies on small scale devices produced at lab-scale. This work was conducted in collaboration with ARMOR and CEA-INES and aims at presenting the application of non-destructive characterization and analysis methods, to explain the evolution under illumination of organic photovoltaic modules (OPV) produced by roll-to-roll on an industrial pilot line. We will present the development and use of imaging methods (electroluminescence, photoluminescence), variable illumination measurement and modeling to explain the differences in performances after manufacturing and after aging between cells and OPV modules. This work has thus made it possible to highlight the disparities existing within modules and cells resulting from the same manufacturing process. In addition, some of the causes of degradation of these modules under illumination have been identified and mitigation strategies have been proposed.

This thesis represents a comprehensive examination of the phonotactic behaviour (i.e. attraction to sound) of the female Gryllus bimaculatus under laboratory conditions. Chapter 2 is the first study to analyze the effect of substrate texture on walking performance in crickets. Substrate texture is found to play an essential role in the phonotactic responses of G. bimaculatus. Smooth substrate texture has a detrimental effect due to slipping, whereas a rough texture results in optimal walking performance due to the friction with the walking legs. Chapter 3 represents the first detailed lifetime study analysing phonotaxis in crickets. My results demonstrate that the optimal age to test phonotaxis in G. bimaculatus females is from day 7 to 24 after the final moult. I also found that selectiveness was persistent with age. These findings contradict the female choosiness hypothesis. This study is also the first to describe the effect of senescence on phonotaxis in insects, as responsiveness decreases with age. Chapter 4 compares the phonotactic behaviour of female crickets from different laboratory-bred colonies. From six tested cricket lab colonies, I found three groups statistically different from each other. Females raised under laboratory conditions at the University of Cambridge and Anglia Ruskin University were most reponsive at a frequency of 4.5 kHz, whereas females bred in Tokushima University in Japan were tuned towards a higher frequency of 5 kHz. These results suggest a degree of artificial allopatric speciation. Comparisons with crickets bred under low-quality conditions in a local pet shop demonstrate a loss of responsiveness, indicating that breeding conditions have a direct effect on phonotactic responsivity. Chapter 5 is the first study to report the presence of phonotaxis in males of G. bimaculatus. Previously it was unknown if G. bimaculatus males were able to perform phonotaxis, given that they were only recognised as endurance signal producers. In the present study, only 20% of the studied males (N=70) performed a weak phonotactic response. This finding has potential ecological implications in terms of male cricket territory establishment, and male-male interactions in the wild, which are discussed. Chapter 6 explores the song pattern recognition of the female G. bimaculatus by changing the duration of either the first, second or third pulse of the chirps. A long first pulse decreased the phonotactic response whereas phonotaxis remained strong when the third pulse was long. Chirps with three pulses of increasing duration of 5, 20 and 50 ms elicited phonotaxis, but the chirps were not attractive when played in reverse order. The data are in agreement with a mechanism in which processing of a sound pulse has an effect on the processing of the subsequent pulse, as outlined in the flow of activity in a delay-line and coincidence-detector circuit.