TY - BOOK A1 - Zhang, Shuhao A1 - Plauth, Max A1 - Eberhardt, Felix A1 - Polze, Andreas A1 - Lehmann, Jens A1 - Sejdiu, Gezim A1 - Jabeen, Hajira A1 - Servadei, Lorenzo A1 - Möstl, Christian A1 - Bär, Florian A1 - Netzeband, André A1 - Schmidt, Rainer A1 - Knigge, Marlene A1 - Hecht, Sonja A1 - Prifti, Loina A1 - Krcmar, Helmut A1 - Sapegin, Andrey A1 - Jaeger, David A1 - Cheng, Feng A1 - Meinel, Christoph A1 - Friedrich, Tobias A1 - Rothenberger, Ralf A1 - Sutton, Andrew M. A1 - Sidorova, Julia A. A1 - Lundberg, Lars A1 - Rosander, Oliver A1 - Sköld, Lars A1 - Di Varano, Igor A1 - van der Walt, Estée A1 - Eloff, Jan H. P. A1 - Fabian, Benjamin A1 - Baumann, Annika A1 - Ermakova, Tatiana A1 - Kelkel, Stefan A1 - Choudhary, Yash A1 - Cooray, Thilini A1 - Rodríguez, Jorge A1 - Medina-Pérez, Miguel Angel A1 - Trejo, Luis A. A1 - Barrera-Animas, Ari Yair A1 - Monroy-Borja, Raúl A1 - López-Cuevas, Armando A1 - Ramírez-Márquez, José Emmanuel A1 - Grohmann, Maria A1 - Niederleithinger, Ernst A1 - Podapati, Sasidhar A1 - Schmidt, Christopher A1 - Huegle, Johannes A1 - de Oliveira, Roberto C. L. A1 - Soares, Fábio Mendes A1 - van Hoorn, André A1 - Neumer, Tamas A1 - Willnecker, Felix A1 - Wilhelm, Mathias A1 - Kuster, Bernhard ED - Meinel, Christoph ED - Polze, Andreas ED - Beins, Karsten ED - Strotmann, Rolf ED - Seibold, Ulrich ED - Rödszus, Kurt ED - Müller, Jürgen T1 - HPI Future SOC Lab – Proceedings 2017 T1 - HPI Future SOC Lab – Proceedings 2017 N2 - The “HPI Future SOC Lab” is a cooperation of the Hasso Plattner Institute (HPI) and industry partners. Its mission is to enable and promote exchange and interaction between the research community and the industry partners. The HPI Future SOC Lab provides researchers with free of charge access to a complete infrastructure of state of the art hard and software. This infrastructure includes components, which might be too expensive for an ordinary research environment, such as servers with up to 64 cores and 2 TB main memory. The offerings address researchers particularly from but not limited to the areas of computer science and business information systems. Main areas of research include cloud computing, parallelization, and In-Memory technologies. This technical report presents results of research projects executed in 2017. Selected projects have presented their results on April 25th and November 15th 2017 at the Future SOC Lab Day events. N2 - Das Future SOC Lab am HPI ist eine Kooperation des Hasso-Plattner-Instituts mit verschiedenen Industriepartnern. Seine Aufgabe ist die Ermöglichung und Förderung des Austausches zwischen Forschungsgemeinschaft und Industrie. Am Lab wird interessierten Wissenschaftlern eine Infrastruktur von neuester Hard- und Software kostenfrei für Forschungszwecke zur Verfügung gestellt. Dazu zählen teilweise noch nicht am Markt verfügbare Technologien, die im normalen Hochschulbereich in der Regel nicht zu finanzieren wären, bspw. Server mit bis zu 64 Cores und 2 TB Hauptspeicher. Diese Angebote richten sich insbesondere an Wissenschaftler in den Gebieten Informatik und Wirtschaftsinformatik. Einige der Schwerpunkte sind Cloud Computing, Parallelisierung und In-Memory Technologien. In diesem Technischen Bericht werden die Ergebnisse der Forschungsprojekte des Jahres 2017 vorgestellt. Ausgewählte Projekte stellten ihre Ergebnisse am 25. April und 15. November 2017 im Rahmen der Future SOC Lab Tag Veranstaltungen vor. T3 - Technische Berichte des Hasso-Plattner-Instituts für Digital Engineering an der Universität Potsdam - 130 KW - Future SOC Lab KW - research projects KW - multicore architectures KW - In-Memory technology KW - cloud computing KW - machine learning KW - artifical intelligence KW - Future SOC Lab KW - Forschungsprojekte KW - Multicore Architekturen KW - In-Memory Technologie KW - Cloud Computing KW - maschinelles Lernen KW - Künstliche Intelligenz Y1 - 2020 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:517-opus4-433100 SN - 978-3-86956-475-3 SN - 1613-5652 SN - 2191-1665 IS - 130 PB - Universitätsverlag Potsdam CY - Potsdam ER - TY - GEN A1 - Kirchartz, Thomas A1 - Márquez, José A. A1 - Stolterfoht, Martin A1 - Unold, Thomas T1 - Photoluminescence-based characterization of halide perovskites for photovoltaics T2 - Zweitveröffentlichungen der Universität Potsdam : Mathematisch-Naturwissenschaftliche Reihe N2 - Photoluminescence spectroscopy is a widely applied characterization technique for semiconductor materials in general and halide perovskite solar cell materials in particular. It can give direct information on the recombination kinetics and processes as well as the internal electrochemical potential of free charge carriers in single semiconductor layers, layer stacks with transport layers, and complete solar cells. The correct evaluation and interpretation of photoluminescence requires the consideration of proper excitation conditions, calibration and application of the appropriate approximations to the rather complex theory, which includes radiative recombination, non-radiative recombination, interface recombination, charge transfer, and photon recycling. In this article, an overview is given of the theory and application to specific halide perovskite compositions, illustrating the variables that should be considered when applying photoluminescence analysis in these materials. T3 - Zweitveröffentlichungen der Universität Potsdam : Mathematisch-Naturwissenschaftliche Reihe - 1419 KW - metal halide perovskites KW - numerical simulations KW - photoluminescence KW - photon recycling Y1 - 2020 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:517-opus4-519702 SN - 1866-8372 IS - 26 ER - TY - JOUR A1 - Kirchartz, Thomas A1 - Márquez, José A. A1 - Stolterfoht, Martin A1 - Unold, Thomas T1 - Photoluminescence-based characterization of halide perovskites for photovoltaics JF - Advanced Energy Materials N2 - Photoluminescence spectroscopy is a widely applied characterization technique for semiconductor materials in general and halide perovskite solar cell materials in particular. It can give direct information on the recombination kinetics and processes as well as the internal electrochemical potential of free charge carriers in single semiconductor layers, layer stacks with transport layers, and complete solar cells. The correct evaluation and interpretation of photoluminescence requires the consideration of proper excitation conditions, calibration and application of the appropriate approximations to the rather complex theory, which includes radiative recombination, non-radiative recombination, interface recombination, charge transfer, and photon recycling. In this article, an overview is given of the theory and application to specific halide perovskite compositions, illustrating the variables that should be considered when applying photoluminescence analysis in these materials. KW - metal halide perovskites KW - numerical simulations KW - photoluminescence KW - photon recycling Y1 - 2020 U6 - https://doi.org/10.1002/aenm.201904134 SN - 1614-6832 SN - 1614-6840 VL - 10 IS - 26 SP - 1 EP - 21 PB - Wiley CY - Weinheim ER - TY - JOUR A1 - Kegelmann, Lukas A1 - Tockhorn, Philipp A1 - Wolff, Christian Michael A1 - Márquez, José A. A1 - Caicedo Dávila, Sebastián A1 - Korte, Lars A1 - Unold, Thomas A1 - Loevenich, Wilfried A1 - Neher, Dieter A1 - Rech, Bernd A1 - Albrecht, Steve T1 - Mixtures of Dopant-Free Spiro-OMeTAD and Water-Free PEDOT as a Passivating Hole Contact in Perovskite Solar Cells JF - ACS applied materials & interfaces N2 - Doped spiro-OMeTAD at present is the most commonly used hole transport material (HTM) in n-i-p-type perovskite solar cells, enabling high efficiencies around 22%. However, the required dopants were shown to induce nonradiative recombination of charge carriers and foster degradation of the solar cell. Here, in a novel approach, highly conductive and inexpensive water-free poly(3,4-ethylenedioxythiophene) (PEDOT) is used to replace these dopants. The resulting spiro-OMeTAD/PEDOT (SpiDOT) mixed films achieve higher lateral conductivities than layers of doped spiro-OMeTAD. Furthermore, combined transient and steady-state photoluminescence studies reveal a passivating effect of PEDOT, suppressing nonradiative recombination losses at the perovskite/HTM interface. This enables excellent quasi-Fermi level splitting values of up to 1.24 eV in perovskite/SpiDOT layer stacks and high open-circuit voltages (V-OC) up to 1.19 V in complete solar cells. Increasing the amount of dopant-free spiro-OMeTAD in SpiDOT layers is shown to enhance hole extraction and thereby improves the fill factor in solar cells. As a consequence, stabilized efficiencies up to 18.7% are realized, exceeding cells with doped spiro-OMeTAD as a HTM in this study. Moreover, to the best of our knowledge, these results mark the lowest nonradiative recombination loss in the V-OC (140 mV with respect to the Shockley-Queisser limit) and highest efficiency reported so far for perovskite solar cells using PEDOT as a HTM. KW - perovskite solar cell KW - selective contact KW - spiro-OMeTAD KW - PEDOT KW - recombination KW - passivation KW - quasi-Fermi level splitting Y1 - 2019 U6 - https://doi.org/10.1021/acsami.9b01332 SN - 1944-8244 SN - 1944-8252 VL - 11 IS - 9 SP - 9172 EP - 9181 PB - American Chemical Society CY - Washington ER - TY - JOUR A1 - Stolterfoht, Martin A1 - Caprioglio, Pietro A1 - Wolff, Christian Michael A1 - Marquez, Jose A. A1 - Nordmann, Joleik A1 - Zhang, Shanshan A1 - Rothhardt, Daniel A1 - Hörmann, Ulrich A1 - Amir, Yohai A1 - Redinger, Alex A1 - Kegelmann, Lukas A1 - Zu, Fengshuo A1 - Albrecht, Steve A1 - Koch, Norbert A1 - Kirchartz, Thomas A1 - Saliba, Michael A1 - Unold, Thomas A1 - Neher, Dieter T1 - The impact of energy alignment and interfacial recombination on the internal and external open-circuit voltage of perovskite solar cells JF - Energy & environmental science N2 - Charge transport layers (CTLs) are key components of diffusion controlled perovskite solar cells, however, they can induce additional non-radiative recombination pathways which limit the open circuit voltage (V-OC) of the cell. In order to realize the full thermodynamic potential of the perovskite absorber, both the electron and hole transport layer (ETL/HTL) need to be as selective as possible. By measuring the photoluminescence yield of perovskite/CTL heterojunctions, we quantify the non-radiative interfacial recombination currents in pin- and nip-type cells including high efficiency devices (21.4%). Our study comprises a wide range of commonly used CTLs, including various hole-transporting polymers, spiro-OMeTAD, metal oxides and fullerenes. We find that all studied CTLs limit the V-OC by inducing an additional non-radiative recombination current that is in most cases substantially larger than the loss in the neat perovskite and that the least-selective interface sets the upper limit for the V-OC of the device. Importantly, the V-OC equals the internal quasi-Fermi level splitting (QFLS) in the absorber layer only in high efficiency cells, while in poor performing devices, the V-OC is substantially lower than the QFLS. Using ultraviolet photoelectron spectroscopy and differential charging capacitance experiments we show that this is due to an energy level mis-alignment at the p-interface. The findings are corroborated by rigorous device simulations which outline important considerations to maximize the V-OC. This work highlights that the challenge to suppress non-radiative recombination losses in perovskite cells on their way to the radiative limit lies in proper energy level alignment and in suppression of defect recombination at the interfaces. Y1 - 2019 U6 - https://doi.org/10.1039/c9ee02020a SN - 1754-5692 SN - 1754-5706 VL - 12 IS - 9 SP - 2778 EP - 2788 PB - Royal Society of Chemistry CY - Cambridge ER - TY - JOUR A1 - Stolterfoht, Martin A1 - Wolff, Christian Michael A1 - Marquez, Jose A. A1 - Zhang, Shanshan A1 - Hages, Charles J. A1 - Rothhardt, Daniel A1 - Albrecht, Steve A1 - Burn, Paul L. A1 - Meredith, Paul A1 - Unold, Thomas A1 - Neher, Dieter T1 - Visualization and suppression of interfacial recombination for high-efficiency large-area pin perovskite solar cells JF - Nature Energy N2 - The performance of perovskite solar cells is predominantly limited by non-radiative recombination, either through trap-assisted recombination in the absorber layer or via minority carrier recombination at the perovskite/transport layer interfaces. Here, we use transient and absolute photoluminescence imaging to visualize all non-radiative recombination pathways in planar pintype perovskite solar cells with undoped organic charge transport layers. We find significant quasi-Fermi-level splitting losses (135 meV) in the perovskite bulk, whereas interfacial recombination results in an additional free energy loss of 80 meV at each individual interface, which limits the open-circuit voltage (V-oc) of the complete cell to similar to 1.12 V. Inserting ultrathin interlayers between the perovskite and transport layers leads to a substantial reduction of these interfacial losses at both the p and n contacts. Using this knowledge and approach, we demonstrate reproducible dopant-free 1 cm(2) perovskite solar cells surpassing 20% efficiency (19.83% certified) with stabilized power output, a high V-oc (1.17 V) and record fill factor (>81%). KW - Energy science and technology KW - Solar cells Y1 - 2018 U6 - https://doi.org/10.1038/s41560-018-0219-8 SN - 2058-7546 VL - 3 IS - 10 SP - 847 EP - 854 PB - Nature Publ. Group CY - London ER - TY - JOUR A1 - Caprioglio, Pietro A1 - Zu, Fengshuo A1 - Wolff, Christian Michael A1 - Prieto, Jose A. Marquez A1 - Stolterfoht, Martin A1 - Becker, Pascal A1 - Koch, Norbert A1 - Unold, Thomas A1 - Rech, Bernd A1 - Albrecht, Steve A1 - Neher, Dieter T1 - High open circuit voltages in pin-type perovskite solar cells through strontium addition JF - Sustainable Energy & Fuels N2 - The incorporation of even small amounts of strontium (Sr) into lead-base hybrid quadruple cation perovskite solar cells results in a systematic increase of the open circuit voltage (V-oc) in pin-type perovskite solar cells. We demonstrate via absolute and transient photoluminescence (PL) experiments how the incorporation of Sr significantly reduces the non-radiative recombination losses in the neat perovskite layer. We show that Sr segregates at the perovskite surface, where it induces important changes of morphology and energetics. Notably, the Sr-enriched surface exhibits a wider band gap and a more n-type character, accompanied with significantly stronger surface band bending. As a result, we observe a significant increase of the quasi-Fermi level splitting in the neat perovskite by reduced surface recombination and more importantly, a strong reduction of losses attributed to non-radiative recombination at the interface to the C-60 electron-transporting layer. The resulting solar cells exhibited a V-oc of 1.18 V, which could be further improved to nearly 1.23 V through addition of a thin polymer interlayer, reducing the non-radiative voltage loss to only 110 meV. Our work shows that simply adding a small amount of Sr to the precursor solutions induces a beneficial surface modification in the perovskite, without requiring any post treatment, resulting in high efficiency solar cells with power conversion efficiency (PCE) up to 20.3%. Our results demonstrate very high V-oc values and efficiencies in Sr-containing quadruple cation perovskite pin-type solar cells and highlight the imperative importance of addressing and minimizing the recombination losses at the interface between perovskite and charge transporting layer. Y1 - 2019 U6 - https://doi.org/10.1039/c8se00509e SN - 2398-4902 VL - 3 IS - 2 SP - 550 EP - 563 PB - Royal Society of Chemistry CY - Cambridge ER -