Bonnes Pratiques de Mesure des Performances des cellules Photovoltaïques

National audienceDans un contexte énergétique tendu, la démonstration de solutions technologiques alternatives efficaces constitue un enjeu majeur. Dans le domaine du photovoltaïque, les filières émergentes (cellules organiques et hybrides) promettent de belles perspectives, avec notamment des rendements pour la première fois supérieurs à 20% démontrés en 2014. Néanmoins, la compétition au niveau international s’accompagne parfois d’annonces de performances parfois mal évaluées, en raison de protocoles de caractérisation inadaptés ou éloignés des standards.Dans ce contexte, il s’avère important de rappeler les méthodes et protocoles adaptés à la caractérisation des performances photovoltaïques, notamment à l’échelle des laboratoires. Au cours de l’exposé, je décrirais ainsi les bonnes pratiques de caractérisation des rendements de conversion de puissance sous éclairement solaire standard, en abordant la problématique de calibration des simulateurs solaires et de la correction spectrale. La mesure des rendements quantiques externes (EQE ou IPCE) et internes (IQE) sera aussi abordée

Improving/Boosting perovskite solar cells performance by using high quality TiO2/graphene-based nanocomposites as electron transport layer

International audienceIn the context of energy transition, development of efficient and cost-effective solar cells is a major objective to establish an optimal energy mix. The 3 rd generation of photovoltaic cells emerged to develop high efficient and low-cost cells combining the use of abundant materials and easy processes. Among them, photovoltaic cells based on perovskite materials demonstrated several significant advances with power conversion efficiencies up to 22% [1][2]. Nevertheless, efforts remain to be performed to improve the charge generation and collection of this kind of cell. Titanium dioxide mesoporous layer, while remaining an important component for perovskite structuration and electron transport in high efficiency devices, can indeed still promote charge trapping and recombination. As carbon nanostructures are good electron transporters, the use of TiO2/graphene nanocomposites seems to be a relevant strategy to reduce recombination phenomena and thus improve electron collection [3]. To achieve high quality of nanocomposites presenting well-controlled physical properties suitable for efficient and stable solar cells, we use the singular technique of laser pyrolysis, which enables to synthetize nanoparticles in a single step with a continuous flow. Attention is payed to the materials properties and their role and effect within solar cells. Tests were conducted with a MAPI-Cl perovskite deposited in a single-step following a reported procedure [4]. Our first results show a better electron injection efficiency from the perovskite to the mesoporous TiO2 layer with graphene, observed through steady-state photoluminescence spectroscopy. This tendency has been reinforced by devices performance that show larger photocurrents and smaller series resistance under standard illumination. More generally an increase in power conversion efficiency from 14.1 % to 15.1 % for these devices is reached for perovskite solar cells containing graphene in the mesoporous layer, demonstrating the benefit of the laser pyrolysis process for the production of high quality electron transport layer

Correlation of mitokines with clinical variables of COPD

RESUMEN : Introducción: La Enfermedad Pulmonar Obstructiva Crónica (EPOC) es una de las enfermedades más prevalentes en nuestro medio. Las exacerbaciones de esta enfermedad presentan una importante morbi-mortalidad. Hasta el momento, no existe ningún biomarcador analítico que permita diagnosticar una agudización de la EPOC. Objetivo: Estudiar las alteraciones que se producen en las mitoquinas en una cohorte que incluye EPOC estables, EPOC agudizados y un grupo control de fumadores sanos. Evaluar la posible utilidad diagnóstica de las mitoquinas en pacientes agudizados y la correlación de las mitoquinas con distintas variables clínicas de la EPOC. Metodología: Estudio transversal en el que se midieron los niveles séricos de FGF-21, GDF-15, MOTS-c, Humanina y variables clínicas relevantes de la EPOC en 166 participantes (40 controles, 95 EPOC estable y 31 agudizados). Resultados: Los niveles de FGF-21 (pg/ml), Humanina (pg/ml) y MOTS-c (ng/ml) fueron menores en los pacientes agudizados que en los EPOC estables (p=0,01; p=0,002 y p<0,001 respectivamente). Mientras que los niveles séricos de GDF-15 (pg/ml) estaban más altos en los pacientes agudizados que en los pacientes con EPOC estable (p<0,001). Al estudiar las correlaciones entre las mitoquinas y distintas variables clínicas de la EPOC comprobamos que los niveles de FGF-21 (pg/ml) correlacionaban negativamente con la puntuación en el CAT (r=-0,240 p=0,031) y positivamente con FEV1 medido en porcentaje (r=0,246 p=0,021) y en mililitros (r=0,253 p=0,017). Por su parte, GDF-15 (pg/ml) correlacionó negativamente con el T6MM (r=-0,363 p=0,001) y positivamente con la edad (r=0,464 p=0,000). También observamos la potencial utilidad diagnóstica de los niveles de GDF-15 (pg/ml) (AUC=0,707) y de MOTS-c (ng/ml) (AUC=0,806) para diagnosticar una agudización. Conclusión: Los niveles de FGF-21, GDF15, MOTS-c y Humanina están alterados durante las agudizaciones de la EPOC. Algunas de estas mitoquinas correlacionan con ciertas variables clínicas. GDF-15 y MOTS-c podrían ser útiles para diagnosticar las agudizaciones de la EPOC.ABSTRACT : Introduction: Chronic Obstructive Pulmonary Disease (COPD) is one of the most prevalent diseases in our environment. Exacerbations of this disease present significant morbidity and mortality. To date, there is no analytical biomarker that allows the diagnosis of an exacerbation of COPD Objective: To study the alterations in mitokines in a cohort that includes stable COPD, exacerbated COPD and a control group of healthy smokers. To evaluate the possible diagnostic utility of mitokines in exacerbated patients and the correlation of mitokines with different clinical variables of COPD. Methods: Cross-sectional study in which serum levels of FGF-21, GDF-15, MOTS-c, Humanin and relevant clinical variables of COPD were measured in 166 subjects (40 controls, 95 stable COPD and 31 exacerbated). Results: The levels of FGF-21 (pg/ml), Humanin (pg/ml) and MOTS-c (ng/ml) were lower in exacerbated patientsthan in stable COPD (p=0,01; p=0,002 and p<0,001 respectively). While the serum levels of GDF-15 (pg/ml) were higher in exacerbated patients than in patients with stable COPD (p<0,001). When studying the correlations between mitokines and different clinical variables of COPD, we verified that the levels of FGF-21 (pg/ml) correlated negatively with the CAT score (r=-0,240 p=0,031) and positively with FEV1 measured in percentage (r=0,246 p=0,021) and in milliliters (r=0,253 p=0,017). On the other hand, GDF-15 (pg/ml) correlated negatively with T6MM (r=-0,363 p=0,001) and positively with age (r=0,464 p=0,000). We also observed the potential diagnostic utility of GDF-15 (pg/ml) (AUC=0,707) and MOTS-c (ng/ml) (AUC=0,806) levels to diagnose exacerbation. Conclusion: The levels of FGF-21, GDF15, MOTS-c and Humanin are altered during exacerbations of COPD. Some of these mitokines correlate with certain clinical variables. GDF-15 and MOTS-c could be useful in to diagnose exacerbations of COPDGrado en Medicin

Multifunctional derivatives of dimethoxy-substituted triphenylamine containing different acceptor moieties

This project has received funding from the Research Council of Lithuania (LMTLT), Agreement No. [S-LZ-19-2]. This research was funded by the Région Centre, the Tunisian ministry of research, University of Monastir and the French ministry of Higher Education and Research. J. Bouclé would like to thank the Sigma-Lim LabEx environment for financial supports, and the PLATINOM facility at XLIM laboratory regarding device fabrication and characterizations. DG acknowledges the Lithuanian Academy of Sciences for the financial support.Two compounds, having dimethoxy-substituted triphenylamino groups and fragments of cyanoacrylic acid or rhodanine-3-acetic acid were prepared and characterized. Their optical, photophysical, thermal, electrochemical, photoelectrical and nonlinear optical properties were investigated. Both derivatives showed ability of glass-formation with glass transition temperatures of 83 and 61 °C. They showed comparable ionization potential values of ca. 5.20 eV. The compounds showed Kerr and two photon absorption effects. The dye containing a rhodanine-3-acetic acid fragment, namely 2-((E)-5-(4-(diphenylamino)benzylidene)-tetrahydro-4-oxo-2-thioxothiophen-3-yl)acetic acid, exhibited a promising power conversion efficiency of 2.09% in dye-sensitized solar cells using the spiro-OMeTAD as hole transporting compound.Research Council of Lithuania Agreement No. [S-LZ-19-2]; Région Centre; Tunisian ministry of research; University of Monastir; French ministry of Higher Education and Research; Institute of Solid State Physics, University of Latvia as the Center of Excellence has received funding from the European Union’s Horizon 2020 Framework Programme H2020-WIDESPREAD-01-2016-2017-TeamingPhase2 under grant agreement No. 739508, project CAMART

The violent youth of bright and massive cluster galaxies and their maturation over 7 billion years

In this study, we investigate the formation and evolution mechanisms of the brightest cluster galaxies (BCGs) over cosmic time. At high redshift (z ∼ 0.9), we selected BCGs and most massive cluster galaxies (MMCGs) from the Cl1604 supercluster and compared them to low-redshift (z ∼ 0.1) counterparts drawn from the MCXC meta-catalogue, supplemented by Sloan Digital Sky Survey imaging and spectroscopy. We observed striking differences in the morphological, colour, spectral, and stellar mass properties of the BCGs/MMCGs in the two samples. High-redshift BCGs/MMCGs were, in many cases, star-forming, late-type galaxies, with blue broad-band colours, properties largely absent amongst the low-redshift BCGs/MMCGs. The stellar mass of BCGs was found to increase by an average factor of 2.51 ± 0.71 from z ∼ 0.9 to z ∼ 0.1. Through this and other comparisons, we conclude that a combination of major merging (mainly wet or mixed) and in situ star formation are the main mechanisms which build stellar mass in BCGs/MMCGs. The stellar mass growth of the BCGs/MMCGs also appears to grow in lockstep with both the stellar baryonic and total mass of the cluster. Additionally, BCGs/MMCGs were found to grow in size, on average, a factor of ∼3, while their average Sérsic index increased by ∼0.45 from z ∼ 0.9 to z ∼ 0.1, also supporting a scenario involving major merging, though some adiabatic expansion is required. These observational results are compared to both models and simulations to further explore the implications on processes which shape and evolve BCGs/MMCGs over the past ∼7 Gyr

Interactions (polymers conjugués/sensibilisateurs semi-conducteurs) pour cellules solaires sensibilisées solides à hautes performances

Revue de veilleNational audienc

Des oxides métalliques aux pérovskites halogénées : Aperçu des dispositifs optoélectroniques hybrides à XLIM

National audienc

Synthesis of analogs of marin alkaloids with potential anti-tumoral activity

En ce début de 21ème siècle, le cancer fait plusieurs millions de victimes dans le monde chaque année. Si cette maladie s’affirme comme un problème de santé publique, le souci économique qu'il exerce auprès des sociétés n'est pas moins important.Les Carbazoles et les Pyrroloiminoquinones sont des familles de molécules très diversifiées appartenant aux alcaloïdes, pouvant offrir de nombreuses activités thérapeutiques notamment en tant qu'anticancéreux. Si la liste des molécules actives connues et leurs traitements liés aux molécules d'origine naturelle ou synthétique est longue, il apparaît clairement que la recherche de nouvelles structures reste importante encore aujourd'hui afin de proposer de nouveaux traitements ou de mieux comprendre cette pathologie.Dans cette démarche et à travers divers objectifs d'intérêt chimique, ce mémoire présente la synthèse de différents composés, analogues de ces molécules naturelles à potentiel antitumoral, avec comme particularité le noyau 4,4-diméthyl-1 ,2,3,4-tétrahydroquinoléine.At this beginning of 21th century, the cancer makes several million victims in the world every year. If this disease asserts itself as a problem of public health, the economic concern which it exercises with societies isnot less important.Carbazoles and Pyrroloirninoquinones are families of very diversified molecules belonging to alkaloids,being able to offer numerous therapeutic activities in particular as anticancer drugs.If the list of the known active molecules and their treatments connected to the molecules of natural orsynthetic origin is long, it seems c1 early that the research for new structures remains important even today topropose of new treatment or to understand better this pathology. In our approach and through diverse objectives of chemical interest, this report present the synthesis of variouscompounds, analogues of these natural molecules with potentiel antitumoral properties, with as particularity the 4,4-dimethyl-1 ,2,3,4-tetrahydroquinoleine pattern

Nouveaux colorants organiques pour cellules solaires sensibilisées à colorant de type p à l’état solide

National audienc

Composites Hybrides Organiques/Inorganiques Pour la Conversion de l'Énergie et l'Optoélectronique

Au cours de cette synthèse destinée à mon Habilitation à Diriger des Recherches, je dresse dans un premier temps le bilan de mes contributions menées sur la période 2005-2014 et centrées sur l’étude de systèmes hybrides organiques/inorganiques variés pour l’optique non linéaire et l’optoélectronique. En particulier, j’aborderai les spécificités des matériaux inorganiques nanostructurés, puis celles des matériaux organiques -conjugués, avant d’illustrer les phénomènes physiques originaux découlant de leur association. Les développements effectués depuis ma nomination au sein de l’Institut XLIM (UMR 7252, Université de Limoges/CNRS) en 2007 illustreront plus directement mon implication dans le domaine de la conversion photovoltaïque de l’énergie, avec notamment un travail particulier dédié aux cellules solaires hybrides à l’état solide, ainsi qu’aux composites polymères semi-conducteurs / nano-objets. Fort de cette expérience pluridisciplinaire dans le domaine des Nanotechnologies, de la caractérisation physique et optoélectronique, ainsi que des processus photo-physiques associés, je proposerai finalement des contributions à court terme et à plus long terme dans les domaines de la récupération d’énergie et des télécommunications optiques sans fils