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Le marché africain des fertilisants organiques est en expansion en raison du faible statut organique des sols et de l'acceptation croissante, parmi les agriculteurs de la fertilisation organo- minérale. Cette étude visait à déterminer les effets d’un fertilisant organique sur des cultures maraichères et sur quelques propriétés physicochimiques d’un sol hydromorphe. Ainsi, deux cucurbitacées (courgette et concombre) ont été cultivées selon un dispositif en blocs de Fisher complètement randomisés. Sept (07) traitements en trois (03) répétitions ont été comparés : Compost Nofosuo (CN) ; Compost Nofosuo + Fumure Organique (CN+FO) ; Compost Nofosuo + Fumure Minérale Vulgarisée (CN+NPK) ; Compost Nofosuo + Fumure Organique + Fumure Minérale Vulgarisée (CN+FO+NPK) ; Fumure Organique (FO) et Fumure Minérale Vulgarisée (NPK + urée). Les données sur les caractères agro morphologiques des cultures ont été collectées. Les résultats ont montré que les rendements de courgette et de concombre ont été significativement affectés par les traitements. Les plus hauts rendements ont été obtenus avec les combinaisons entre le compost Nofosuo et la fumure minérale NPK. Les traitements combinant le compost Nofosuo a la fumure minérale et organo-minérale (CN+NPK et CN+FO+NPK) ont permis d’obtenir des gains additionnels de rendement de plus de 100% par rapport au traitement de l’engrais minéral NPK seul pour les deux cucurbitacées. Le compost Nofosuo apporté seul ou combiné aux engrais solubles ou à la fumure organique a entrainé une diminution de l’acidité des sols hydromorphes sous les deux cultures. L’apport combiné du compost Nofosuo avec les engrais solubles a aussi amélioré le phosphore total et la matière organique du sol. Le compost Nofosuo apparait ainsi comme une alternative de maintien de la fertilité des sols sur les périmètres maraichers à fort usage d’engrais chimiques. English title: Characterization of a hydromorphic soil physico-chemical properties resulted from a biofertilizer amendment in cucurbit production in Burkina Faso The expansion of africain market organic fertilizers resulted from low soil organic statute and the increasing adoption of organo-mineral fertilization among farmers. This study aimed to determine the effects of an organic fertilizer on vegetable crops and on some hydromorphic soil physico-chemical properties. Two cucurbits (zucchini and cucumber) were grown using randomised Fisher bloc design. 7 treatments in 3 replications were compared: Nofosuo Compost (NC); Nofosuo Compost + Organic Fertilizer (OF); Nofosuo Compost + Mineral Fertilizer (MF), NC+MF+MF; FO and MF (NPK). Data were collected on the crops agromorphological parameters. Results showed that the yields of zucchini and cucumber were significant influenced by the treatments. The highest yields obtained from the combination of NC with MF (NC+NPK and NC+OF+NPK) contributed to increase the two cucurbit yield up to 100% compared to NPK treatment alone. Nofusuo compost applied alone or combined with mineral fertilizers or with organic fertilizer led to the hydrorphic soil acidity decrease under the two cucurbits. The combined used of Nofosuo compost with mineral fertilizers improved total phosphorus and soil organic matter contents. Nofosuo compost could be therefore considered as an alternative to maintain soil fertility in market gardens where chemical fertilizer is much used. &nbsp

L’inadéquation de la fertilisation minérale est une contrainte qui limite la production du sorgho et du mil au Burkina Faso. Cette étude vise à déterminer l’effet des nutriments secondaires et des micronutriments (NSM) dans la production du sorgho et du mil sur des sols ferrugineux tropicaux lessivés du Burkina Faso. Elle a été conduite en station expérimentale à Saria de 2018 à 2019. Le dispositif expérimental est constitué d’un bloc de Fisher avec trois répétitions. Sept traitements ont été comparés : Témoin (0), NPK (60-15-20), NPK+S (60-15-20-15S), NPK+Mg (60-15-20-10Mg), NPK+Zn (60-15-20-2,5Zn), NPK+B (60-15-20-0,5B) et Complet (60-15-20-15S-10Mg-2,5Zn-0,5B). Le rendement grain du sorgho a été significativement augmenté avec les traitements combinant les NSM au macronutriment. Contrairement au sorgho, cette combinaison a entraîné une baisse des rendements grain du mil. Les rendements grains du sorgho ont augmenté de 40% en 2018 avec les traitements Complet, NPK+S, NPK+Zn et NPK+Mg. En 2019, ces augmentations ont été de 53%, 23% et 16% respectivement avec les traitements Complet, NPK+B et NPK+S par rapport au NPK. L’apport d’engrais composé de NPK combiné au NSM et à la matière organique est une alternative pour accroître durablement les rendements des céréales. The inadequacy of mineral fertilization is a constraint that limits the production of sorghum and millet in Burkina Faso. This study aimed at determining the effect of secondary nutrients and micronutrients (NSM) in the production of cereals on leached tropical ferruginous soils from Burkina Faso. It was conducted in the Saria experimental station from 2018 to 2019. The experimental design consisted of a Fisher block with three repetitions. Seven treatments were compared: Control without fertilizers (0), NPK (60-15-20), NPK + S (60-15-20-15S), NPK + Mg (60-15-20-10Mg), NPK + Zn (60-15-20-2,5Zn), NPK + B (60-15-20-0,5B) and Complete (60-15-20-15S-10Mg-2,5 Zn-0,5B). The grain yield of sorghum was significantly increased with the addition of NSM to the NPK. However, millet grain yield was decline with NSM addition to NPK treatment. The Complete, NPK + S, NPK + Zn and NPK + Mg treatments showed 40% increasing in grain yield of sorghum compared to NPK in 2018. Complete, NPK + B and NPK + S treatments which increased the grain yield of sorghum by 53%, 23% and 16% respectively in 2019. Adding NPK fertilizer combined with NSM and organic matter is an alternative to achieve sustainable increasing of grains yields.

Additional file 1: Table S1. File containing, supplementary tables (S1-S5), supplementry figures (S1 - S18) and supplementary methods andresults.

Authors are grateful to Maksym Kovalenko and Andriy Stelmakh for useful discussions and providing the MD snapshots.; International audience; The interfacial properties between perovskite photoactive and charge transport layers are critical for device performance and operational stability. Therefore, an accurate theoretical description of the link between surface dipoles and work functions is of scientific and practical interest. We show that for a CsPbBr 3 perovskite surface functionalized by dipolar ligand molecules, the interplay between surface dipoles, charge transfers, and local strain effects leads to upward or downward shifts of the valence level. We further demonstrate that the contribution of individual molecular entities to the surface dipoles and electric susceptibilities are essentially additive. Finally, we compare our results to those predicted from conventional classical approaches based on a capacitor model that links the induced vacuum level shift and the molecular dipole moment. Our findings identify recipes to fine-tune materials work functions that provide valuable insights into the interfacial engineering of this family of semiconductors.

International audience; Halide perovskites have captivated the research community over the past decade mainly in the photovoltaic field as a new generation of absorber materials for high-efficiency and low-cost solar cells. Nowadays, the power conversion efficiency (PCE) is reaching 25.7% for single cells and 31.3% for Perovskite/Si tandem cells. Moreover, halide perovskites exhibit attractive potential for Lasers, LEDs, Photodetectors, Photocatalysis. Nevertheless, despite promising low manufacturing costs, short payback time and abundant material resources, the potential industrial use of halide perovskites is still be hampered by toxicity issues, device stability and upscaling. Researchers are also looking for alternative materials related to the substitution of Pb by Sn in standard halide perovskite structures, double perovskite structures, perovskite-like structures or even non-perovskite structures such as rudorfittes. Importantly, the low-bandgap Pb-Sn alloyed perovskite allows the building of all-perovskite tandem solar cells that shall overcome the performances of single-junction perovskite cells. In fact, of all possible means to improve perovskite film quality and suppress nonradiative recombination in optoelectronic devices for a high photo conversion efficiency purpose, the surface and interface functionalizations after the assembly with charge transport layer (CTL) are one of the most critical parameters . In view of the sophisticated chemical and physical properties of Sn-based perovskites, theoretical calculations based on density functional theory (DFT) may provide a useful insight into the interplay between absorbers and CTLs. Here, FASnI3 is chosen as a benchmark material. We thoroughly investigate the influence of its surface termination on structural and electronic properties when interfacing with organic C60 (100) and inorganic SnO2 (100) and (110), including the intermediate work function calculations on the free-standing slabs. Based on the theoretical methology developed in our team, we have evidenced the proportionality between work function shifts and surface dipoles, providing an additional microscopic insight into interfacial properties in lead-free heterostructures.

International audience; Interplay between structural and photophysical properties of metal halide perovskites is critical to their utility in optoelectronics, but there is limited understanding of lattice response upon photoexcitation. Here, 2D perovskites butylammonium lead iodide, (BA) PbI , and phenethylammonium lead iodide, (PEA) PbI , are investigated using ultrafast transient X-ray diffraction as a function of optical excitation fluence to discern structural dynamics. Both powder X-ray diffraction and time-resolved photoluminescence linewidths narrow over 1 ns following optical excitation for the fluence range studied, concurrent with slight redshifting of the optical bandgaps. These observations are attributed to transient relaxation and ordering of distorted lead iodide octahedra stimulated mainly by electron-hole pair creation. The c axis expands up to 0.37% over hundreds of picoseconds; reflections sampling the a and b axes undergo one tenth of this expansion with the same timescale. Post-photoexcitation appearance of the (110) reflection in (BA) PbI would suggest a transient phase transition, however, through new single-crystal XRD, reflections are found that violate glide plane conditions in the reported Pbca structure. The static structure space group is reassigned as P2 2 2 . With this, a nonequilibrium phase transition is ruled out. These findings offer increased understanding of remarkable lattice response in 2D perovskites upon excitation.

National audience; The presentation will focus on the interplay between structural, interfacial and optoelectronic properties in 2D multilayered halide perovskites, either in Ruddlesden Popper (RP) or Dion Jacobson (DJ) structure. At present, perovskite materials are mixed with each other in complex alloys and heterostructures, including 2D/3D compositions, combined with additives or protecting layers to improve their stability and/or defectiveness as well as assembled with carrier selective layers, other materials and components to turn them into devices. Considering the target applications, ambient conditions predominate with additional issues related, for example, to the intrinsic dynamics in action in the MHP structure that may not be well captured using static averaged structures.Based on a set of customized examples, this talk will summarize recent theoretical results obtained by our group that aimed at answering questions such as: i) How do these engineering strategies impact the work function and absolute valence band energy of the MHP material? ii) Is it correlated with surface/interface dipoles? iii) Can one quantitatively assess energy level alignments of MHP semiconductors based on first-principles electronic structure calculations? How can one get rid of the stochastic dynamics of organic cations and further include cation and anion alloying while computing materials properties? iv) Is it possible to extract semi-empirical formula for molecular passivation at surface or transitivity rules for interface dipoles?Special attention will be paid on newly discovered phases and compositions and opportunities to further engineer MHP properties in connection with their use in devices under working conditions. We will see that in practical cases the funneling of electronic carriers to the 2D crystal edges, important for ionization of electron-hole pairs in 2D RP phases, is also at work in bromide perovskites. Continuous and ultrafast photodoping will be further discussed, demonstrating their strong impact on the structural and carrier transport properties of DJ perovskites

International audience

International audience; The considerable attention paid to metal halide perovskites (MHP) in recent years led to several scientific and technological advances. This in turn raised important questions that currently challenge the limits of available theoretical techniques and atomistic models. At present, perovskite materials are mixed with each other in complex alloys and heterostructures, including 2D/3D compositions, combined with additives or protecting layers to improve their stability and/or defectiveness as well as assembled with carrier selective layers, other materials and components to turn them into devices. Considering the target applications, ambient conditions predominate with additional issues related, for example, to the intrinsic dynamics in action in the MHP structure that may not be well captured using static averaged structures.Based on a set of customized examples, this talk will summarize recent theoretical results obtained by our group that aimed at answering questions such as: i) How do these engineering strategies impact the work function and absolute valence band energy of the MHP material? ii) Is it correlated with surface/interface dipoles? iii) Can one quantitatively assess energy level alignments of MHP semiconductors based on first-principles electronic structure calculations? How can one get rid of the stochastic dynamics of organic cations and further include cation and anion alloying while computing materials properties? iv) Is it possible to extract semi-empirical formula for molecular passivation at surface or transitivity rules for interface dipoles? Special attention will be paid on newly discovered phases and compositions and opportunities to further engineer MHP properties in connection with their use in devices under working conditions.*This research received funding from the European Union’s Horizon 2020 program, through and Innovation Action under the grant agreement No. 861985 (PeroCUBE). J.E. acknowledges the Institut Universitaire de France.

International audience

International audience

International audience; In the past years, solution-processed organometallic perovskite based solar cells have emerged as a promising low-cost thin-film photovoltaic technology. 3D halide perovskite semiconductors and their 2D or OD nanostructures present specific symmetry and electronic properties, including giant spin-orbit coupling (SOC) effects. The ultrahigh softness of the halide perovskite lattice is also characteristic, and the role of the electron-phonon coupling, especially at temperatures relevant for device operation, is not fully understood. The presentation will focus on 2D perovskites, composed of perovskites layers sandwiched between two layers of large organic cations, described in the 90’s as self-assembled quantum and dielectric well systems.

National audience; Used alone or associated with a 3D structure in a 2D/3D heterojunction, two-dimensional (2D) halide perovskites have recently emerged as a game changer in the field of perovskites solar cells thanks to their excellent optoelectronic properties combined with an enhanced material stability.

Objectifs : cette étude vise à déterminer l'effet des fertilisants biologiques sur les paramètres physico-chimiques des sols et sur la productivité de la tomate (Lycopersicon esculentum Mill.) en zone sub-saharienne du Burkina Faso. Méthodologie et résultats : un dispositif en bloc de Fisher complètement randomisé constitué de 6 traitements avec 3 répétitions. Les traitements comparés étaient : T0 : témoin absolu ; T1 : Compost enrichi au Trichoderma harzianum + 175 kg ha-1 de NPK + 50 kg ha-1 d’urée, T2 : Compost enrichi au Trichoderma harzianum ; T3 : 350 kg ha-1de NPK + 100 kg ha-1 d’urée ; T4 : Bokashi + 175 kg ha-1 de NPK + 50 kg ha-1 d’urée ; T5 : compost Bokashi. Par rapport au témoin absolu, les résultats montrent que T2 et T5 entrainent une augmentation significative du rendement de 170% et 76% respectivement. Conclusion et application des résultats : ces résultats ont montré que les deux composts biologiques ont eu un effet bénéfique sur la production de la tomate et sur les paramètres physico-chimiques du sol. Le compost enrichi au Trichoderma harzianum se révèle être le plus rentable et la plus efficace sur le rendement comparativement au compost Bokashi. Ce dernier (Bokashi) n’est efficace qu’en association avec la fumure minérale vulgarisée (FMV). En effet, l’association compost Bokashi plus FMV a entrainé une hausse de rendement de 274,5% par rapport à T0. L’utilisation de ces composts en agriculture pourrait être une alternative pour la production durable de la tomate. Leur vulgarisation à la dose de 30 t. ha-1 pourrait être recommandée pour un bon rendement de la tomate. English abstract Objective: This study aims to evaluate the effect of organic fertilizers on soil physico-chemical properties and on tomato productivity (Lycopersicon esculentum Mill.) in Sub-Saharan Africa. Methodology and results: used of a completely randomized Fisher block design with 6 treatments in 3 replications. The applied treatments were: T0: control; T1: Compost enriched with Trichoderma harzianum + 175 kg ha-1 NPK + 50 kg ha-1 urea; T2: Compost enriched with Trichoderma harzianum; T3: 350 kg ha-1 NPK + 100 kg ha-1 urea; T4: Bokashi + 175 kg ha-1 NPK + 50 kg ha-1 urea; T5: Bokashi compost. Compared to the control, results show that T2 and T5 significantly increased yield by 170% and 76% respectively. Conclusion and application of results: These results showed that both composts are benefic in tomato production and soil physico-chemical properties improvement. Compost enriched with Trichoderma harzianum was the most cost-effective and efficient than Bokashi compost, which is only effective when combined with mineral fertilizer (FMV). Bokashi compost combined with FMV contributed to improve yield up to 274.5% compared to T0. Using these composts in agriculture could be an economic alternative for sustainable tomato production. The rate of 0.5 t/ha could be recommended and disseminated for better yields. Key words: Bokashi, Trichoderma Harzianum, Tomato yield, Burkina Faso

Following the emergence of lead halide perovskites as record-breaking materials for emerging photovoltaic applications, lead-free perovskites are gaining interest as novel materials which are compatible with inkjet-printing based technologies1,2,3. Bulk properties are of the prime importance, but charge transport can be rapidly altered across the interface of perovskite/ (hole or electron) transport layer (HTL or ETL). Yet, due to the size and complexity of the interface systems, a thorough ab initio modeling of the interfaces remains elusive to-date. Within this work, to explore the atomic-scale details of the structural and electronic properties of these materials, we employ state-of-the-art density functional theory (DFT) based calculations of model tin-based heterostructures. We investigate in particular three-dimensional corner-sharing Sn-based perovskites, their surface and interface properties and calculate the interaction of the materials with charge transport layers (CTLs). Our approach reveals the electronic band alignments and dielectric mismatches between perovskite layers and the most important hole and electron transport layers that have been used in prototype thin film device architectures4,5. In an effort to understand the fundamental physico-chemical mechanisms that govern the interactions between the photo-active absorber material and CTLs, we also probe the influence of surface termination on structural and electronic properties at FASnI3/C60 (as ETL) interfaces and FASnI3/NiOx (as ETL) interfaces. Our findings give a detailed insight into the interface engineering necessary for optimizing the next generation of environmental-friendly high-performing opto-electronic devices. This DROP-IT project1 has received funding from the European Union’s Horizon 2020 research and innovation Program under the grant agreement No 862656. The information and views set out in the abstracts and presentations are those of the authors and do not necessarily reflect the official opinion of the European Union. Neither the European Union institutions and bodies nor any person acting on their behalf may be held responsible for the use which may be made of the information contained herein. References: (1) DROPIT https://www.uv.es/dropit/ (accessed June 22, 2021). (2) Volonakis, G.; Filip, M. R.; Haghighirad, A. A.; Sakai, N.; Wenger, B.; Snaith, H. J.; Giustino, F. Lead-Free Halide Double Perovskites via Heterovalent Substitution of Noble Metals. J. Phys. Chem. Lett. 2016, 7 (7), 1254–1259. https://doi.org/10.1021/acs.jpclett.6b00376. (3) Volonakis, G.; Haghighirad, A. A.; Milot, R. L.; Sio, W. H.; Filip, M. R.; Wenger, B.; Johnston, M. B.; Herz, L. M.; Snaith, H. J.; Giustino, F. Cs2InAgCl6: A New Lead-Free Halide Double Perovskite with Direct Band Gap. J. Phys. Chem. Lett. 2017, 8 (4), 772–778. https://doi.org/10.1021/acs.jpclett.6b02682. (4) Traore, B.; Pedesseau, L.; Blancon, J.-C.; Tretiak, S.; Mohite, A. D.; Even, J.; Katan, C.; Kepenekian, M. Importance of Vacancies and Doping in Hole Transporting Nickel Oxide Interface with Halide Perovskites. ACS Appl. Mater. Interfaces 2020. https://doi.org/10.1021/acsami.9b19457. (5) Canicoba, N. D.; Zagni, N.; Liu, F.; McCuistian, G.; Fernando, K.; Bellezza, H.; Traoré, B.; Rogel, R.; Tsai, H.; Le Brizoual, L.; et al. Halide Perovskite High-k Field Effect Transistors with Dynamically Reconfigurable Ambipolarity. ACS Materials Lett. 2019, 1 (6), 633–640. https://doi.org/10.1021/acsmaterialslett.9b00357.

ACS Award in the Chemistry of Materials (2020): Symposium Honoring David Brian Mitzi; International audience; Layered halide perovskites are a class of semiconductors produced via chemical approaches andshowing unique opto-electronic properties. Pioneered by Prof. David Mitzi in the 1990s, these materials have anatural quantum-well electronic structure (the band-gap of the inorganic frame is embedded into that of theorganic spacers) and feature positive transport properties, effective visible-light absorption, narrow excitonicemission, etc.The full exploitation of these perovskites cannot go without deep understanding of their native electronic andoptical properties, as accessible, via complex experimental set-ups and computationally expensive ab-initiocalculations. However, interpretation of experimental and theoretical results can greatly benefit from basic“pencil-and-paper” symmetry analysis. Based on group-theory, we discuss how the change in thedimensionality influences the corresponding electronic and optical properties. In the direct band gap quantumwellscenario, we highlight how the breaking of the chemical connectivity influences the electronic structure, interms of hybridization of the composing atoms (see Figure a). We also discuss the corresponding evolution ofthe optical properties, with focus on the lowest energy exciton fine structure. The present analysis will be thenextended to the case of defective-halide perovskite frames, a class of systems recently reported in theliterature.As an alternative scenario, substitution of commonly used saturated organic spacers with molecules featuringextended π-conjugation breaks the quantum-well picture. Indeed, the band-gap closing due to extended π-system can result in the (de)stabilization of the frontier orbitals of the spacer, compared to those of theinorganic frame, leading to the formation of a type II heterojunction at the organic/inorganic interface (seeFigure b). We discuss the related charge/energy transfer processes on the basis of recently reportedPbX (X=Cl,Br) layered perovskite frame incorporating tetrazine derivative as spacer. Featuring resonancesboth for the single particle states and excitonic states, these systems allow to discuss several diversionchannels for the relaxation of carriers generated in the perovskite, in the detail.

International audience; Abstract Body: Currently, many different perovskite -with corner-sharing octahedra- as well as non-perovskite metal-halide solids are synthetized worldwide entailing the need for in-depth understanding of their structure/property relationships. In this regard, combining the huge accumulated knowledge over the last decades, on halide but also oxide perovskites, with modern atomic scale modeling as well as symmetry analysis has proved useful. Among others, new compositions such as A'2An-1MnX3n+1 (where A and A' are cations, X is halide and M is metal) afford layered structures with a controlled number (n, currently ? 7) of octahedra in the perovskite layer. Those correspond to innate heterostructures that offer an ideal platform for fundamental understanding such as effect of quantum or dielectric confinement.[1] Efforts have also been successful in building new perovskite structures with cations surpassing the Goldschmidt tolerance factor. For instance, this has been recently demonstrated for layered perovskites with the use of ethylammonium, isopropylammonium or dimethylammonium as perovskitizer, having a perovskite sheet retaining its continuous corner-sharing connectivity.[2] On another note, new three dimensional networks have been achieved by mixing larger cations (e.g., hydroxyethylammonium) with the standard ones (e.g. methylammonium, formamidinium) leading to the formation of voids in the perovskite lattice, either disordered (Hollow perovskites) or with structural signature of a periodic pattern (Deficient perovskites).[3] In this talk, I will discuss some of our recent theoretical results paying attention on newly discovered halide perovskite phases and opportunities to further engineer their properties in connection with their use in devices. References including references therein: [1] C. Katan, N. Mercier, J. Even, Quantum and dielectric Confinement Effects in Lower-Dimensional Hybrid Perovskite Semiconductors, Chem. Rev. 119, 3140 (2019); [2] Y. Fu, X. Jiang, X. Li, B. Traore, I. Spanopoulos, C. Katan, J. Even, M. G. Kanatzidis, E. Harel, Cation Engineering in Two-Dimensional Ruddlesden-Popper Lead Iodide Perovskites with Mixed Large A-Site Cations in the Cages, J. Am. Chem. Soc. 142, 4008 (2020); X. Li, Y. Fu, L. Pedesseau, P. Guo, S. Cuthriell, I. Hadar, J. Even, C. Katan, C. C. Stoumpos, R. D. Schaller, E. Harel, M. G. Kanatzidis, Negative Pressure Engineering with Large Cage Cations in 2D Halide Perovskites Causes Lattice Softening, J. Am. Chem. Soc. (2020) DOI: 10.1021/jacs.0c03860; [3] A. Leblanc, N. Mercier, M. Allain, J. Dittmer, T. Pauporté, V. Fernandez, F. Boucher, M. Kepenekian, C. Katan, Enhanced Stability and Band Gap Tuning of ?-[HC(NH2)2]PbI3 Hybrid, ACS Appl. Mater. Interfaces, 11, 20743 (2019); C. Zheng, O. Rubel, M. Kepenekian, X. Rocquefelte, C. Katan, Electronic properties of Pb-I deficient lead halide perovskites, J. Chem. Phys. 151, 234704 (2019); C. Quarti, C. Katan and J. Even, Physical properties of bulk, defective, 2D and 0D metal halide perovskite semiconductors from a symmetry perspective, under revision.