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L'étude du comportement inhérent au transport de charge induit par le champ des pérovskites d'halogénure de plomb 3D est restée en grande partie une tâche difficile, principalement en raison des effets indésirables de la migration ionique près de la température ambiante. En outre, la présence de méthylammonium dans de nombreuses compositions de pérovskite 3D hautement performantes introduit des instabilités supplémentaires, qui limitent le fonctionnement fiable des dispositifs optoélectroniques à température ambiante. Ici, nous abordons ces deux défis et démontrons que les transistors à effet de champ (FET) à base de compositions de pérovskite sans méthylammonium et à métaux mélangés (Pb/Sn), qui sont largement étudiés pour les applications de cellules solaires et de diodes électroluminescentes, ne souffrent pas d'effets de migration ionique comme leurs homologues Pb purs et présentent de manière fiable un transport de type p sans hystérésis avec une mobilité élevée atteignant 5,4 $cm^2/Vs$ , un rapport ON/OFF approchant 10 $ ^6 $ et une conductance de canal normalisée de 3 S/m. La migration ionique réduite se manifeste également par une dépendance à la température activée de la mobilité à effet de champ avec une faible énergie d'activation, ce qui reflète une densité significative de défauts électroniques peu profonds. Nous visualisons la migration ionique dans le plan supprimée dans les pérovskites contenant du Sn par rapport à leurs homologues de Pb pur en utilisant la microscopie à photoluminescence sous polarisation et démontrons des stabilités opérationnelles prometteuses du dispositif de tension et de contrainte de courant. Notre travail établit les FET comme une excellente plate-forme pour fournir des informations fondamentales sur le dopage, les défauts et la physique du transport de charge des semi-conducteurs à pérovskite halogénure de métal mélangé afin de faire progresser leurs applications dans les dispositifs optoélectroniques. La investigación del comportamiento inherente de transporte de carga impulsado por el campo de las perovskitas de haluro de plomo 3D ha seguido siendo en gran medida una tarea difícil, debido principalmente a los efectos indeseables de la migración iónica cerca de la temperatura ambiente. Además, la presencia de metilamonio en muchas composiciones de perovskita 3D de alto rendimiento introduce inestabilidades adicionales, que limitan el funcionamiento confiable del dispositivo optoelectrónico a temperatura ambiente. Aquí, abordamos ambos desafíos y demostramos que los transistores de efecto de campo (FET) basados en composiciones de perovskita de metal mixto (Pb/Sn) sin metilamonio, que se estudian ampliamente para aplicaciones de células solares y diodos emisores de luz, no sufren efectos de migración de iones como sus contrapartes de Pb puro y exhiben de manera confiable transporte de tipo p libre de histéresis con una alta movilidad que alcanza los 5.4 $cm^2/Vs$, una relación de encendido/APAGADO cercana a $ 10^6 $ y una conductancia de canal normalizada de 3 S/m. La migración iónica reducida también se manifiesta en una dependencia de la temperatura activada de la movilidad del efecto de campo con baja energía de activación, lo que refleja una densidad significativa de defectos electrónicos poco profundos. Visualizamos la migración iónica suprimida en el plano en perovskitas que contienen Sn en comparación con sus contrapartes de Pb puro utilizando microscopía de fotoluminiscencia bajo polarización y demostramos estabilidades operativas prometedoras del dispositivo de tensión y corriente. Nuestro trabajo establece los FET como una excelente plataforma para proporcionar información fundamental sobre el dopaje, los defectos y la física del transporte de carga de los semiconductores de perovskita de haluro de metal mixto para avanzar en sus aplicaciones en dispositivos optoelectrónicos. Investigation of the inherent field-driven charge transport behaviour of 3D lead halide perovskites has largely remained a challenging task, owing primarily to undesirable ionic migration effects near room temperature. In addition, the presence of methylammonium in many high performing 3D perovskite compositions introduces additional instabilities, which limit reliable room temperature optoelectronic device operation. Here, we address both these challenges and demonstrate that field-effect transistors (FETs) based on methylammonium-free, mixed-metal (Pb/Sn) perovskite compositions, that are widely studied for solar cell and light-emitting diode applications, do not suffer from ion migration effects as their pure Pb counterparts and reliably exhibit hysteresis free p-type transport with high mobility reaching 5.4 $cm^2/Vs$, ON/OFF ratio approaching $10^6$, and normalized channel conductance of 3 S/m. The reduced ion migration is also manifested in an activated temperature dependence of the field-effect mobility with low activation energy, which reflects a significant density of shallow electronic defects. We visualize the suppressed in-plane ionic migration in Sn-containing perovskites compared to their pure-Pb counterparts using photoluminescence microscopy under bias and demonstrate promising voltage and current-stress device operational stabilities. Our work establishes FETs as an excellent platform for providing fundamental insights into the doping, defect and charge transport physics of mixed-metal halide perovskite semiconductors to advance their applications in optoelectronic devices. ظل التحقيق في سلوك نقل الشحنة المتأصل الذي يحركه المجال لبيروفسكايت الرصاص ثلاثي الأبعاد مهمة صعبة إلى حد كبير، ويرجع ذلك في المقام الأول إلى تأثيرات الهجرة الأيونية غير المرغوب فيها بالقرب من درجة حرارة الغرفة. بالإضافة إلى ذلك، فإن وجود الميثيل أمونيوم في العديد من تركيبات البيروفسكايت ثلاثية الأبعاد عالية الأداء يؤدي إلى عدم استقرار إضافي، مما يحد من تشغيل الجهاز الإلكتروني البصري الموثوق في درجة حرارة الغرفة. هنا، نتصدى لكل من هذه التحديات ونوضح أن الترانزستورات ذات التأثير الميداني (FETs) القائمة على تركيبات البيروفسكايت الخالية من الميثيل أمونيوم والمختلطة المعادن (Pb/SN)، والتي تتم دراستها على نطاق واسع للخلايا الشمسية وتطبيقات الصمام الثنائي الباعث للضوء، لا تعاني من تأثيرات هجرة الأيونات كنظيراتها النقية من Pb وتظهر بشكل موثوق نقل p - type الخالي من التباطؤ مع حركة عالية تصل إلى 5.4 $cm^2/Vs$، ونسبة ON/OFF تقترب من $ 10^6 $، وتوصيل القناة الطبيعي لـ 3 S/m. تتجلى هجرة الأيونات المنخفضة أيضًا في الاعتماد المنشط على درجة الحرارة لحركة التأثير الميداني مع طاقة تنشيط منخفضة، مما يعكس كثافة كبيرة من العيوب الإلكترونية الضحلة. نتصور الهجرة الأيونية المكبوتة داخل الطائرة في البيروفسكايت المحتوية على Sn مقارنة بنظيراتها النقية من Pb باستخدام المجهر الضوئي تحت التحيز ونوضح الثبات التشغيلي الواعد للجهد وجهاز الإجهاد الحالي. يؤسس عملنا FETs كمنصة ممتازة لتوفير رؤى أساسية في فيزياء نقل المنشطات والعيوب والشحن لأشباه موصلات هاليد البيروفسكايت المختلطة المعادن لتعزيز تطبيقاتها في الأجهزة الإلكترونية الضوئية.

Subglacial hydrologic systems regulate ice sheet flow, causing acceleration or deceleration depending on hydraulic efficiency and the rate at which surface meltwater is delivered to the bed. Because these systems are rarely observed, ice sheet basal drainage represents a poorly integrated and uncertain component of models used to predict sea-level changes. Here, we report radar-derived basal melt rates and unexpectedly warm subglacial conditions beneath a large Greenlandic outlet glacier. The basal melt rates averaged 14 mm d−1 over 4 months, peaking at 57 mm d−1 when basal wa-ter temperature reached +0.88 C in a nearby borehole. We attribute both observations to the conversion of potential energy of surface water as heat in the basal drainage system, which peaked during a period of rainfall and intense surface melting. Our findings reveal limitations in the theory of channel formation and we show that viscous dissipation far surpasses other basal heat sources, even in a distributed, high-pressure system.

This dataset contains the underlying data for the following publication: I. Sognnaes, A. Gambhir, D.-J. Van de Ven, A. Nikas, A. Anger-Kraavi, H. Bui, L. Campagnolo, E. Delpiazzo, H. Doukas, S. Giarola, N. Grant, A. Hawkes, A. Koberle, A. Kolpakov, S. Mittal, J. Moreno, S. Perdana, J. Rogelj, M. Vielle, & G.P. Peters. (2021). A multi-model analysis of long-term emissions and warming implications of current mitigation efforts. Nature Climate Change.

This dataset contains the underlying data for the following publication: Giarola, S., Mittal, S., Vielle, M., Perdana, S., Campagnolo, L., Delpiazzo, E., ... & van de Ven, D. J. (2021). Challenges in the harmonisation of global integrated assessment models: A comprehensive methodology to reduce model response heterogeneity. Science of the Total Environment, 783, 146861. https://doi.org/10.1016/j.scitotenv.2021.146861.

We present quantitative ultrafast interferometric pump-probe microscopy capable of tracking of photoexcitations with sub 10 nm spatial precision in three dimensions with 15 fs temporal reso- lution, through retrieval of the full transient photoinduced complex refractive index. We use this methodology to study the spatiotemporal dynamics of the quantum coherent photophysical process of ultrafast singlet exciton fission. Measurements on microcrystalline pentacene films grown on glass (SiO2) and boron nitride (hBN) reveal a 25 nm, 70 fs expansion of the joint-density-of-states along the crystal a,c-axes accompanied by a 6 nm, 115 fs change in the exciton density along the crystal b-axis. We propose that photogenerated singlet excitons expand along the direction of max- imal orbital π-overlap in the crystal a,c-plane to form correlated triplet pairs, which subsequently electronically decouples into free triplets along the crystal b-axis due to molecular sliding motion of neighbouring pentacene molecules. Our methodology lays the foundation for the study of three dimensional transport on ultrafast timescales.

Heterostructures of two-dimensional (2D) transition metal dichalcogenides (TMDs) and inorganic semiconducting zero-dimensional (0D) quantum dots (QDs) offer unique charge and energy transfer pathways which could form the basis of novel optoelectronic devices. To date, most has focused on charge transfer and energy transfer from QDs to TMDs, i.e. from 0D to 2D. Here, we present a study of the energy transfer process from a 2D to 0D material, specifically exploring energy transfer from monolayer tungsten disulphide ($WS_{2}$) to near infrared (NIR) emitting lead sulphide-cadmium sulphide (PbS-CdS) QDs. The high absorption cross section of $WS_{2}$ in the visible region combined with the potentially high photoluminescence (PL) efficiency of PbS QD systems, make this an interesting donor-acceptor system that can effectively use the WS2 as an antenna and the QD as a tuneable emitter, in this case downshifting the emission energy over hundreds of meV. We study the energy transfer process using photoluminescence excitation (PLE) and PL microscopy, and show that 58% of the QD PL arises due to energy transfer from the $WS_{2}$. Time resolved photoluminescence (TRPL) microscopy studies show that the energy transfer process is faster than the intrinsic PL quenching by trap states in the $WS_{2}$, thus allowing for efficient energy transfer. Our results establish that QDs could be used as tuneable and high PL efficiency emitters to modify the emission properties of TMDs. Such TMD-QD heterostructures could have applications in light emitting technologies, artificial light harvesting systems or be used to read out the state of TMD devices optically in various logic and computing applications

With the deadline to reach net-zero quickly approaching, the aviation industry will soon have to shift away from kerosene aircraft. One of the candidate zero-emissions technologies for future aircraft is hydrogen. However, due to the technology being yet immature, the implementation of hydrogen on aircraft is expected to be a long-term endeavour. To accelerate this process, a study has been conducted to evaluate the feasibility of hydrogen-kerosene hybrid combustion as a stepping stone towards full hydrogen implementation. Three goals have been defined: to estimate first-order performance of future hydrogen combustion aircraft, to bring understanding to the hydrogen combustion design space, and to identify a potential pathway for the implementation of hydrogen combustion. To achieve these, simulations have been run using a computational model of a hydrogen retrofit of a ATR 72-500 with engines capable of hybrid combustion. An optimization approach was used to explore this new design space without biases. To accurately reflect the importance of each optimization objective, Tabu Search with Multiple Dominance Relations was chosen as the optimizer. The results of this investigation have revealed fundamental trade-offs in the retrofit design space and provided a set of optimized aircraft of varying hybridisation fraction that can pave the pathway towards full hydrogen implementation in aircraft.

This dataset provides raw and processed data generated in the experimental campaign: “Wave dissipation and transformation over coastal vegetation under extreme hydrodynamic loading”. The experiments were performed in the Large Wave Flume (Grosser Wellenkanal, GWK) of Forschungszentrum Küste (FZK) in Hannover, Germany. The objectives of the experiments were Quantify the role of vegetation on wave attenuation under extreme conditions that are essential for flood defence designs; Identify water depth / wave height / wave steepness thresholds that mark the transition from (a) conditions in which vegetation has a negligible effect on wave energy to (b) those regimes where vegetation significantly affects waves, to (c) those conditions that cause bed/canopy/plant ‘failure’/’breakage’; Quantify the forces and response of two species types (Elymus and Puccinellia), at the front of the vegetated section to the various depth/energy regimes; Quantify the effect of a non-vegetated marsh platform on waves, for comparison with the effects of the vegetated platform (control condition). Observations and measurements were based on a submerged vegetated platform of approximately one wave length (40 m) subjected to irregular waves of different characteristics. The tested vegetation was made up of typical north-western European species-rich middle to high elevation marsh communities. The data acquisition covered The wave characteristics in front of, over, and behind the platform; Current velocity profiles above the vegetation; Point flow velocities; Plant stem density; Soil surface profiles; Net floating organic debris, and Forces exerted on real and artificial plants mounted in front of the test platform. In addition to measurements, the plant movements and the whole experimental area were video recorded. Due to their very large sizes, video recordings cannot be placed to this repository. This data and the data from number 4 to 6 of the list above may be provided on demand. Please contact the manager of the FZK laboratory. More information about the experiments may be found in the auxiliary files (see the readme.txt file) provided here, and associated publications as follows: Möller, I., Kudella, M., Rupprecht, F., Spencer, T., Paul, M., Wesenbeeck, B.K. van, Wolters, G., Jensen, K., Bouma, T.J., Miranda-Lange, M., Schimmels, S., 2014. Wave attenuation over coastal salt marshes under storm surge conditions. Nature Geoscience 7, ngeo2251. https://doi.org/10.1038/ngeo2251 Rupprecht, F., Möller, I., Paul, M., Kudella, M., Spencer, T., van Wesenbeeck, B.K., Wolters, G., Jensen, K., Bouma, T.J., Miranda-Lange, M., Schimmels, S., 2017. Vegetation-wave interactions in salt marshes under storm surge conditions. Ecological Engineering 100, 301–315. https://doi.org/10.1016/j.ecoleng.2016.12.030 Spencer, T., Möller, I., Rupprecht, F., Bouma, T.J., van Wesenbeeck, B.K., Kudella, M., Paul, M., Jensen, K., Wolters, G., Miranda-Lange, M., Schimmels, S., 2016. Salt marsh surface survives true-to-scale simulated storm surges. Earth Surf. Process. Landforms 41, 543–552. https://doi.org/10.1002/esp.3867