cometadata/datacite-rtg-text-other-reclassification-records huggingface dataset:
Stellar yields from metal-rich asymptotic giant branch models
Creators: name: Karakas, Amanda I.
name: Lugaro, Maria
Publisher: name: arXiv
Year: 2016
Subjects: subject: Solar and Stellar Astrophysics (astro-ph.SR)
subject: Astrophysics of Galaxies (astro-ph.GA)
subject: FOS: Physical sciences

description: We present new theoretical stellar yields and surface abundances for three grids of metal-rich asymptotic giant branch (AGB) models. Post-processing nucleosynthesis results are presented for stellar models with initial masses between 1$M_{\odot}$ and 7.5$M_{\odot}$ for $Z=0.007$, and 1$M_{\odot}$ and 8$M_{\odot}$ for $Z=0.014$ (solar) and $Z=0.03$. We include stellar surface abundances as a function of thermal pulse on the AGB for elements from C to Bi and for a selection of isotopic ratios for elements up to Fe and Ni (e.g., $^{12}$C/$^{13}$C), which can be obtained from observations of molecules in stars and from the laboratory analysis of meteoritic stardust grains. Ratios of elemental abundances of He/H, C/O, and N/O are also included, which are useful for direct comparison to observations of AGB stars and their progeny including planetary nebulae. The integrated elemental stellar yields are presented for each model in the grid for hydrogen, helium and all stable elements from C to Bi. Yields of Li are also included for intermediate-mass models with hot bottom burning. We present the first $slow$ neutron-capture ($s$-process) yields for super-solar metallicity AGB stars with $Z=0.03$, and the first complete $s$-process yields for models more massive than 6$M_{\odot}$ at all three metallicities.
description: 20 pages, 20 figures, includes supplementary surface abundance and yield data tables; accepted for publication in ApJ
Effect of group organization on the performance of cooperative processes
Creators: name: Reia, Sandro M.
name: Fontanari, José F.
Publisher: name: arXiv
Year: 2016
Subjects: subject: Social and Information Networks (cs.SI)
subject: Adaptation and Self-Organizing Systems (nlin.AO)
subject: Physics and Society (physics.soc-ph)
subject: FOS: Computer and information sciences
subject: FOS: Physical sciences

description: Problem-solving competence at group level is influenced by the structure of the social networks and so it may shed light on the organization patterns of gregarious animals. Here we use an agent-based model to investigate whether the ubiquity of hierarchical networks in nature could be explained as the result of a selection pressure favoring problem-solving efficiency. The task of the agents is to find the global maxima of NK fitness landscapes and the agents cooperate by broadcasting messages informing on their fitness to the group. This information is then used to imitate, with a certain probability, the fittest agent in their influence networks. For rugged landscapes, we find that the modular organization of the hierarchical network with its high degree of clustering eases the escape from the local maxima, resulting in a superior performance as compared with the scale-free and the random networks. The optimal performance in a rugged landscape is achieved by letting the main hub to be only slightly more propense to imitate the other agents than vice versa. The performance is greatly harmed when the main hub carries out the search independently of the rest of the group as well as when it compulsively imitates the other agents.
Results from the KASCADE-Grande data analysis
Creators: name: Kang, Donghwa
name: Apel, W. D.
name: Arteaga-Velázquez, J. C.
name: Bekk, K.
name: Bertaina, M.
name: Blümer, J.
name: Bozdog, H.
name: Cantoni, E.
name: Chiavassa, A.
name: Cossavella, F.
name: Daumiller, K.
name: Souza, V. De
name: Pierro, F. Di
name: Doll, P.
name: Engel, R.
name: Fuhrmann, D.
name: Gherghel-Lascu, A.
name: Gils, H. J.
name: Glasstetter, R.
name: Grupen, C.
name: Haungs, A.
name: Heck, D.
name: Hörandel, J. R.
name: Huege, T.
name: Kampert, K.-H.
name: Klages, H. O.
name: Link, K.
name: Łuczak, P.
name: Mathes, H. J.
name: Mayer, H. J.
name: Milke, J.
name: Morello, C.
name: Oehlschläger, J.
name: Ostapchenko, S.
name: Pierog, T.
name: Rebel, H.
name: Rivera-Rangel, D.
name: Roth, M.
name: Schieler, H.
name: Schoo, S.
name: Schröder, F. G.
name: Sima, O.
name: Toma, G.
name: Trinchero, G. C.
name: Ulrich, H.
name: Weindl, A.
name: Wochele, J.
name: Zabierowski, J.
Publisher: name: Scuola Internazionale Superiore di Studi Avanzati (SISSA)
Year: 2022

description: KASCADE-Grande and its original array of KASCADE were dedicated to measure individual air showers of cosmic rays with great detail in the primary energy range of 100 TeV up to 1 EeV. The experiment has significantly contributed to investigations of the energy spectrum and chemical composition of cosmic rays in the transition region from galactic to extragalactic origin of cosmic rays as well as to the further development of hadronic interaction models through validity tests using the multi-detector information from KASCADE-Grande. Though the data accumulation was completed in 2013, the data analysis is still continuing. Recently, we investigate the reliability of the new hadronic interactions model of the Sibyll version 2.3d with the combined data from KASCADE and KASCADE-Grande, and compare it to the predictions of different hadronic interaction models. In addition, we update the web-based platform of the KASCADE Cosmic Ray Data Centre (KCDC), where now full datasets from KASCADE and KASCADE-Grande and the corresponding Monte-Carlo simulated events are available.
Topological invariants for interacting topological insulators: II. Breakdown of the Green's function formalism
Creators: name: He, Yuan-Yao
name: Wu, Han-Qing
name: Meng, Zi Yang
name: Lu, Zhong-Yi
Publisher: name: arXiv
Year: 2015
Subjects: subject: Strongly Correlated Electrons (cond-mat.str-el)
subject: FOS: Physical sciences

description: Topological phase transitions in free fermion systems can be characterized by closing of single-particle gap and change in topological invariants. However, in the presence of electronic interactions, topological phase transitions are more complicated. In paper I of this series (arXiv:1510.07816), we have developed an efficient scheme to evaluate the topological invariants based on Green's function formalism. Here, in paper II, we demonstrate four interaction-drive topological phase transitions (TPTs) in two-dimensional (2D) interacting topological insulators (TIs) via large-scale quantum Monte Carlo (QMC) simulations, based on the scheme of evaluating topological invariants presented in paper I. Across these transitions, the defining symmetries of the TIs have been neither explicitly nor spontaneously broken. In the first two models, the topological invariants calculated from Green's function formalism succeed in characterizing interaction-driven TPTs. However, in the second two models, we find single-particle gap does not close and the topological invariants constructed from single-particle Green's function acquire no change across the TPTs. Unexpected breakdown of the Green's function formalism in constructing topological invariants is thus discovered. We thence classify the TPTs in interacting TIs into two categories: those have noninteracting correspondence can be characterized successfully by the topological invariants constructed from Green's functions, while for the others that do not have noninteracting correspondence, the Green's function formalism experiences a breakdown but more interesting and exciting phenomena, such as emergent collective critical modes at the transition, arise. Discussion on the success and breakdown of topological invariants constructed from the Green's function formalism in the context of symmetry protected topological (SPT) states is presented.
description: 15 pages, 13 figures
Performance Evaluation and Parametrization of CIGS Thin Film Solar Modules through Multiple Linear Regressions
Creators: name: Farias Basulto, G.A.
name: Reyes-Figueroa, P.
name: Ulbrich, C.
name: Szyszka, B.
name: Schlatmann, R.
name: Klenk, R.
Publisher: name: WIP
Year: 2020
Subjects: Perovskites and Other Non-Silicon Materials, MJs and Tandems
CI(G)S, CdTe and Related Thin Films

description: 37th European Photovoltaic Solar Energy Conference and Exhibition; 627-632
description: For optimum design and accurate yield prediction, it is required to know the parameters of a photovoltaic module as a function of module temperature and irradiation. The commonly available values within the data sheet, such as parameters under STC, temperature coefficients at STC and low light performance at a fixed irradiation, will give a first but not very precise estimation of module parameters at arbitrary irradiation and temperature. We propose a new algorithm that, in contrast to some of the existing approaches, provides equations not only for the maximum power point (Pmpp) output, but also for open circuit voltage, short circuit current, and current at MPP. It uses only a minimum of initial assumptions concerning the module behavior (black box model) which should make it universally applicable for different solar cell technologies. On the other hand, by comparing the black box equations to analytical descriptions of CIGSSe solar cells, we can cross-link both models and derive device physics parameters from the black box representation. Comparison of model based prediction and actual outdoor data collected over several months in Berlin confirms that the black box model offers a simple and intuitive method to predict location/season specific module performance ratios.
Effects of PDT on the Low Temperature Behavior of CIGS Thin-Film Solar Cells
Creators: name: Mücke, D.
name: Vidal Lorbada, R.
name: Walter, T.
name: Schäffler, R.
Publisher: name: WIP
Year: 2020
Subjects: Perovskites and Other Non-Silicon Materials, MJs and Tandems
CI(G)S, CdTe and Related Thin Films

description: 37th European Photovoltaic Solar Energy Conference and Exhibition; 633-635
description: This paper deals with the behavior of Cu(In,Ga)Se2 based solar cells at low temperatures. Special at tent ion is given to the differences between samples from a standard process and with PDT, especially with respect to the back contact barrier. This barrier in form of a Schot tky junct ion is responsible for a t ransistor-like behavior at low temperatures. The height of this barrier can be calculated from IV(T) curves. With the use of dark annealing experiments it could be shown that metastable changes of the doping in the absorber play an important role for the low temperature behavior. Higher doping leads to a lower amplificat ion factor. Aging t reatments with a negat ive bias causes an increase of the barrier height and lower a decrease of the doping concent ration, leading to a higher amplificat ion factor with a blocking of the forward current even at high temperatures.
Field-induced resistivity plateau and unsaturated negative magnetoresistance in topological semimetal TaSb2
Creators: name: Li, Yuke
name: Li, Lin
name: Wang, Jialu
name: Wang, Tingting
name: Xu, Xiaofeng
name: Xi, Chuanying
name: Cao, Chao
name: Dai, Jianhui
Publisher: name: arXiv
Year: 2016
Subjects: subject: Materials Science (cond-mat.mtrl-sci)
subject: FOS: Physical sciences

description: Several prominent transport properties have been identified as key signatures of topologicalmaterials. One is the resistivity plateau at low temperatures as observed in several topological insulators (TIs), another is the negative magnetoresistance (MR) when the applied magnetic field is parallel to the current direction as observed in several topological semimetals (TSMs) including Dirac semimetals (DSMs) and Weyl semimetals (WSMs). Usually, these two exotic phenomena emerge in distinct materials with or without time reversal symmetry (TRS), respectively. Here we report the discovery of a new member in TSMs, TaSb2, which clearly exhibits both of these phenomena in a single material. This compound crystallizes in a base-centered monoclinic, centrosymmetric structure, and is metallic with a low carrier density in the zero field. While applying magnetic field it exhibits insulating behavior before appearance of a resistivity plateau below Tc =13 K. In the plateau regime, the ultrahigh carrier mobility and extreme magnetoresistance (XMR) for the field perpendicular to the current are observed as in DSMs and WSMs, in addition to a quantum oscillation behavior with non-trivial Berry phases. In contrast to the most known DSMs and WSMs, the negative MR in TaSb2 does not saturate up to 9 T, which, together with the almost linear Hall resistivity, manifests itself an electron-hole non-compensated TMS. These findings indicate that the resistivity plateau could be a generic feature of topology-protected metallic states even in the absence of TRS and compatible with the negative MR depending on the field direction. Our experiment extends a materials basis represented by TaSb2 as a new platform for future theoretical investigations and device applications of topological materials.
description: 21pages,3figures
Robust imaging with electromagnetic waves in noisy environments
Creators: name: Borcea, Liliana
name: Garnier, Josselin
Publisher: name: arXiv
Year: 2016
Subjects: subject: Analysis of PDEs (math.AP)
subject: Numerical Analysis (math.NA)
subject: FOS: Mathematics

description: We study imaging with an array of sensors that probes a medium with single frequency electromagnetic waves and records the scattered electric field. The medium is known and homogenous except for some small and penetrable inclusions. The goal of inversion is to locate and characterize these inclusions from the data collected by the array, which are corrupted by additive noise. We use results from random matrix theory to obtain a robust inversion method. We assess its performance with numerical simulations and quantify the benefit of measuring more than one component of the scattered electric field.
description: 27 pages
Dispensing Technology Meets CIGS Substrates: First IV-Results with Dispensed Metal Grid on CIGS Mini-Modules
Creators: name: Gensowski, K.
name: Jimenez Cardozo, A.M.
name: Tepner, S.
name: Kuchler, M.
name: Breitenbücher, M.
name: Freund, T.
name: Köder, P.
name: Müller, J.
name: Dimmler, B.
name: Pospischil, M.
name: Clement, F.
Publisher: name: WIP
Year: 2020
Subjects: Perovskites and Other Non-Silicon Materials, MJs and Tandems
CI(G)S, CdTe and Related Thin Films

description: 37th European Photovoltaic Solar Energy Conference and Exhibition; 636-640
description: For the first time, the parallel dispensing approach and the CIGS thin-film technology are combined to demonstrate metallization for thin-film PV with low temperature pastes. This article focuses on dispensing three different low temperature pastes through 35 μm and 25 μm nozzle openings, respectively, and applying them on 156 mm x 156 mm CIGS substrates. The screen printed metal grid acts as reference. The achieved contact resistivity values are below 5 mcm². The metal grid on the TCO layer of CIGS substrates obtains an increased short-circuit current density of jsc = 1.1 mA∙cm-², which corresponds to 3.5% current density gain compared to grid-free CIGS modules, and an increased module power of up to 4.6%. Additionally, the Fill Factor is positively affected by the metallization. Paste C shows a promising contact finger geometry with a core finger width of wcore = 25 μm ± 1 μm and an optical aspect ratio of ARo= 0.46 ± 0.02. Following, the dispensing technology has been successfully applied on CIGS mini-modules as a future approach for realizing the metallization with a realistic perspective in terms of scalability for large module sizes.
Photon Recycling Mechanisms in Thin-Film GaAs Solar Cells
Creators: name: Gruginskie, N.
name: Cappelluti, F.
name: Tibaldi, A.
name: Bauhuis, G.J.
name: Mulder, P.
name: Vlieg, E.
name: Schermer, J.J.
Publisher: name: WIP
Year: 2020
Subjects: Perovskites and Other Non-Silicon Materials, MJs and Tandems
III-V and Related Compound Semiconductors

description: 37th European Photovoltaic Solar Energy Conference and Exhibition; 618-620
description: In this study, photon recycling mechanisms in single junction thin-film GaAs solar cells are investigated. An approach of theoretical modeling supported by experimentally obtained results is used in order to correlate the reflectance of the cell's rear layers, the photon recycling probability and the solar cell performance. Solar cells with different top and bottom metallization configurations are produced and their performance is optically and electrically analyzed. It is shown that the photon recycling probability increases with the rear mirror reflectance and solar cell thickness, which results in the increase of the devices open circuit voltage. We identify the front grid coverage, which is usually disregarded in rear mirror focused studies, to be strongly reducing the photon recycling probability of the devices. Furthermore, based on preliminary calculations, the internal radiative efficiency of the solar cells seems to prevent further increase of the devices' open circuit voltage as a result of improvements to the rear mirror of the cells. In order to achieve a significant benefit of the increased photon recycling probability to the solar cell performance, the limiting mechanisms hindering the cells internal radiative efficiency need to be identified and properly addressed.
Piecewise linearity in the $GW$ approximation for accurate quasiparticle energy predictions
Creators: name: Dauth, Matthias
name: Caruso, Fabio
name: Kümmel, Stephan
name: Rinke, Patrick
Publisher: name: arXiv
Year: 2015
Subjects: subject: Materials Science (cond-mat.mtrl-sci)
subject: Other Condensed Matter (cond-mat.other)
subject: FOS: Physical sciences

description: We identify the deviation from the straight line error (DSLE) -- i.e., the spurious non-linearity of the total energy as a function of fractional particle number -- as the main source for the discrepancy between experimental vertical ionization energies and theoretical quasiparticle energies, as obtained from the $GW$ and $GW$+SOSEX approximations to many-body perturbation theory (MBPT). For self-consistent calculations, we show that $GW$ suffers from a small DSLE. Conversely, for perturbative $G_0W_0$ and $G_0W_0$+SOSEX calculations the DSLE depends on the starting point. We exploit this starting-point dependence to reduce (or completely eliminate) the DSLE. We find that the agreement with experiment increases as the DSLE reduces. DSLE-minimized schemes, thus, emerge as promising avenues for future developments in MBPT.
Determination of the Back Contact Recombination Velocity of a Cu(In,Ga)Se2/ITO Interface Using Bifacial Solar Cells
Creators: name: Schneider, T.
name: Hölscher, T.
name: Kempa, H.
name: Scheer, R.
Publisher: name: WIP
Year: 2020
Subjects: Perovskites and Other Non-Silicon Materials, MJs and Tandems
CI(G)S, CdTe and Related Thin Films

description: 37th European Photovoltaic Solar Energy Conference and Exhibition; 621-626
description: Bifacial CIGSe solar cells with ITO back contacts and with absorber thicknesses ranging from 300 to 1020 nm were studied by measuring J-V-characteristics and EQE with illumination from front and rear side, respectively. Compared to simultaneously processed samples with Mo back contacts, increased open circuit voltages occured with ITO back contacts. This effect was more pronounced with decreasing absorber thickness and can be related to a possible hole extraction barrier. Systematic electrical simulations were employed to determine the back contact recombination velocity at the CIGSe/ITO interface, resulting in a value of the order of 105 cm/s.
Three circles theorems for harmonic functions
Creators: name: Xu, Guoyi
Publisher: name: arXiv
Year: 2016
Subjects: subject: Differential Geometry (math.DG)
subject: FOS: Mathematics

description: We proved two Three Circles Theorems for harmonic functions on manifolds in integral sense. As one application, on manifold with nonnegative Ricci curvature, whose tangent cone at infinity is the unique metric cone with unique conic measure, we showed the existence of nonconstant harmonic functions with polynomial growth. This existence result recovered and generalized the former result of Y. Ding, and led to a complete answer of L. Ni's conjecture. Furthermore in similar context, combining the techniques of estimating the frequency of harmonic functions with polynomial growth, which were developed by Colding and Minicozzi, we confirmed their conjecture about the uniform bound of frequency.
description: 34pp, to appear on Math. Ann
Perovskite Solar Cells Subjected to Realistic Operating Conditions: Temperature Dependence, Outdoor Monitoring, Energy Yield Modelling
Creators: name: Lipovsek, B.
name: Jost, M.
name: Tomsic, S.
name: Al-Ashouri, A.
name: Brecl, K.
name: Albrecht, S.
name: Topic, M.
Publisher: name: WIP
Year: 2020
Subjects: Perovskites and Other Non-Silicon Materials, MJs and Tandems
Perovskites

description: 37th European Photovoltaic Solar Energy Conference and Exhibition; 611-614
description: In this contribution, we report on comprehensive indoor and outdoor characterization of single-junction perovskite solar cells. In the first set, sample devices are measured under controlled laboratory environment to determine the dependency of various parameters on the cell temperature and incident irradiance. The samples from the second set, on the other hand, are subjected to long-term outdoor monitoring performed at a dedicated testing site using customized equipment. The experimental results in combination with advanced optical simulations are then used to develop an energy yield model that can accurately predict the generated energy of the solar cell based on its structure and known meteorological data. The model is successfully validated. Finally, we demonstrate how the energy yield model can be employed to extract the rate of degradation for each tested solar cell, and also how detailed analysis and optimization of the device structures can be performed by taking the geographical location, the orientation of the device, and the realistic year-long operating condition fully into account.
Realizable monotonicity for continuous-time Markov processes
Creators: name: Pra, Paolo Dai
name: Louis, Pierre-Yves
name: Minelli, Ida
Publisher: name: arXiv
Year: 2016
Subjects: subject: Probability (math.PR)
subject: FOS: Mathematics

description: We formalize and analyze the notions of stochastic monotonicity and realizable mono-tonicity for Markov Chains in continuous-time, taking values in a finite partially ordered set. Similarly to what happens in discrete-time, the two notions are not equivalent. However, we show that there are partially ordered sets for which stochastic monotonicity and realizable monotonicity coincide in continuous-time but not in discrete-time.
Epitaxial GaAs Lift-off from Si(111) Wafer via 2D-GaSe Buffer Layer
Creators: name: Kojima, N.
name: Wang, Y.-C.
name: Ohshita, Y.
name: Yamaguchi, M.
Publisher: name: WIP
Year: 2020
Subjects: Perovskites and Other Non-Silicon Materials, MJs and Tandems
III-V and Related Compound Semiconductors

description: 37th European Photovoltaic Solar Energy Conference and Exhibition; 615-617
description: In recent years, thin film III-V cells using epitaxial lift-off (ELO) technique and substrate re-use has attracted increasing attention as low-cost, high-efficiency, light-weight and flexible solar cells. In this paper, the rapid ELO technique using mechanical cleavage via 2D-layered metal selenide was applied to the epitaxial GaAs layer transfer from 2-inch Si(111) substrate. As 2D-layered metal selenide, double 2D-buffer layers of GaSe and In2Se3 were grown on Si(111) 4o off substrate by MBE. The epitaxial GaAs layer transfer from 2-inch Si(111) wafer onto thin flexible PMMA or polyimide sheet was succeeded by using the thermal stress by liquid nitrogen dipping. The processing time is only around 10 sec. However, a lot of wrinkles were formed during temperature recovery to room temperature in the ELO process. To get smooth ELO-GaAs layer surface, further improvement of the ELO process is necessary. This rapid ELO technique has great potential for the dramatically cost reduction of thin film flexible III-V solar cells than the usual selective etching technique by aqueous acid.
Toward an improved control of the fixed-node error in quantum Monte Carlo: The case of the water molecule
Creators: name: Caffarel, Michel
name: Applencourt, Thomas
name: Giner, Emmanuel
name: Scemama, Anthony
Publisher: name: arXiv
Year: 2016
Subjects: subject: Chemical Physics (physics.chem-ph)
subject: FOS: Physical sciences

description: All-electron Fixed-node Diffusion Monte Carlo (FN-DMC) calculations for the nonrelativistic ground-state energy of the water molecule at equilibrium geometry are presented. The determinantal part of the trial wavefunction is obtained from a perturbatively selected Configuration Interaction calculation (CIPSI method) including up to about 1.4 million of determinants. Calculations are made using the cc-pCV$n$Z family of basis sets, with $n$=2 to 5. In contrast with most QMC works no re-optimization of the determinantal part in presence of a Jastrow is performed. For the largest cc-pCV5Z basis set the lowest upper bound for the ground-state energy reported so far of -76.43744(18) is obtained. The fixed-node energy is found to decrease regularly as a function of the cardinal number $n$ and the Complete Basis Set limit (CBS) associated with {\it exact nodes} is easily extracted. The resulting energy of -76.43894(12) -in perfect agreement with the best experimentally derived value- is the most accurate theoretical estimate reported so far. We emphasize that employing selected CI nodes of increasing quality in a given family of basis sets may represent a simple, deterministic, reproducible, and systematic way of controlling the fixed-node error in DMC.
description: 5 pages, 1 figure
Experiences of Continuous On-Sun Performance Measurements of Perovskite Mini-Modules
Creators: name: Norton, M.
name: Kohlstädt, M.
name: Hadjipanayi, M.
name: Paraskeva, V.
name: Würfel, U.
name: Georghiou, G.E.
Publisher: name: WIP
Year: 2020
Subjects: Perovskites and Other Non-Silicon Materials, MJs and Tandems
Perovskites

description: 37th European Photovoltaic Solar Energy Conference and Exhibition; 606-610
description: A set of Perovskite-based mini-modules have been distributed between testing partners in Cyprus and Germany in order to acquire performance measurements of the devices under long-term outdoor exposure. The devices were tested indoors prior to mounting outdoors where their current-voltage characteristics were recorded at regular intervals over several months using various loading and voltage sweeping strategies. All modules tested showed a decrease in power conversion efficiency over time, though subsequent discoveries have shown that this arose from some recoverable process and is not an irreversible form of degradation. A basic theory is expounded that attributes both long-term performance decline and recovery to the migration of slow-moving ionic species within the Perovskite cells. Furthermore, the same process, with faster ion migration, can explain the observed behaviour of the modules under different voltage sweep and loading strategies. This work has reaffirmed the importance of considering the movement of ions in any I-V tracing strategy and provides a set of recommendations to deal with this. While MPP loading facilitates the measurement of more representative instantaneous device efficiencies, it has not been possible to conclude that real degradation is enhanced when keeping modules at open circuit between scans.
Controlled Laser-Induced PBI2 Formation for Optimized P2 and P3 Patterning of Perovskite Mini-Modules
Creators: name: Schultz, C.
name: Fenske, M.
name: Dagar, J.
name: Junghans, C.
name: Zeiser, A.
name: Bartelt, A.
name: Schlatmann, R.
name: Unger, E.
name: Stegemann, B.
Publisher: name: WIP
Year: 2020
Subjects: Perovskites and Other Non-Silicon Materials, MJs and Tandems
Perovskites

description: 37th European Photovoltaic Solar Energy Conference and Exhibition; 601-605
description: Monolithic series interconnection of perovskite solar cells is necessary for scaling up the currently still small cell sizes. This requires patterning of the individual solar cell layers, preferably by laser. The underlying ablation mechanisms are investigated in this paper to find optimal laser parameters and process windows. It is shown that the use of ns laser pulses produces a larger amount of PbI2 in the processed area than ps laser pulses. The resulting PbI2 was found to be detrimental to the electrical behavior during P2 patterning of the absorber layer, but advantageous for P3 patterning of the back contact. By choosing the laser pulse length, the amount of PbI2 can be controlled and thus the electrical losses can be minimized. In this way, mini-module efficiencies of more than 19% were achieved.
Thermal Analysis of Organic Photovoltaic Modules as Building Elements in Long Term Outdoor Operating Conditions
Creators: name: Toledo Arias, C.A.
name: Bardizza, G.
name: Gracia Amillo, A.M.
name: Abad, J.
name: Urbina, A.
Publisher: name: WIP
Year: 2020
Subjects: Perovskites and Other Non-Silicon Materials, MJs and Tandems
Organic and Dye-Sensitised

description: 37th European Photovoltaic Solar Energy Conference and Exhibition; 587-591
description: Organic photovoltaic (OPV) modules integrated in buildings offer many advantages over conventional PV solutions thanks to high level of integration which combines aesthetics and functionality. Whilst the benefits of the technology are clear, their thermal operation in outdoor environments is essential in order to assess their technical potential in the building industry since, as building element, their thermal behavior affects thermal comfort, electricity generation and service lifetime. This work focuses on the thermal behavior of light-weight and flexible OPV modules mounted as building elements. An experimental set-up with PV modules installed on the faces of a cube is used to test the modules at different orientations working during 2 years at outdoor operating conditions. Faiman model is used to assess the PV module temperature. The determination of empirical parameters gives an accuracy in the range of 3.0 and 4.5 ºC depending on the tilt and orientation. A strong visual degradation mainly due to delamination is observed in those faces which receive higher levels of solar irradiation along the day.
Intrinsic Paramagnetic Meissner Effect due to s-wave Odd-Frequency Superconductivity
Creators: name: Di Bernardo, Angelo
name: Salman, Zaher
name: Wang, Xiaolei
name: Amado, Mario
name: Egilmez, Mehmet
name: Flokstra, Machiel
name: Suter, Andreas
name: Lee, Steve
name: Zhao, Jianhua
name: Prokscha, Thomas
name: Morenzoni, Elvezio
name: Blamire, Mark
name: Linder, Jacob
name: Robinson, Jason W. A.
Publisher: name: arXiv
Year: 2016
Subjects: subject: Superconductivity (cond-mat.supr-con)
subject: FOS: Physical sciences

description: In 1933, Meissner and Ochsenfeld reported the expulsion of magnetic flux, the diamagnetic Meissner effect, from the interior of superconducting lead. This discovery was crucial in formulating the Bardeen-Cooper-Schrieffer (BCS) theory of superconductivity. In exotic superconducting systems BCS theory does not strictly apply. A classical example is a superconductor-magnet hybrid system where magnetic ordering breaks time-reversal symmetry of the superconducting condensate and results in the stabilisation of an odd-frequency superconducting state. It has been predicted that under appropriate conditions, odd-frequency superconductivity should manifest in the Meissner state as fluctuations in the sign of the magnetic susceptibility meaning that the superconductivity can either repel (diamagnetic) or attract (paramagnetic) external magnetic flux. Here we report local probe measurements of faint magnetic fields in a Au/Ho/Nb trilayer system using low energy muons, where antiferromagnetic Ho (4.5 nm) breaks time-reversal symmetry of the proximity induced pair correlations in Au. From depth-resolved measurements below the superconducting transition of Nb we observe a local enhancement of the magnetic field in Au that exceeds the externally applied field, thus proving the existence of an intrinsic paramagnetic Meissner effect arising from an odd-frequency superconducting state.
Detection of binary and multiple systems among rapidly rotating K and M dwarf stars from Kepler data
Creators: name: Oláh, Katalin
name: Rappaport, Saul
name: Joss, Matthew
Publisher: name: arXiv
Year: 2016
Subjects: subject: Solar and Stellar Astrophysics (astro-ph.SR)
subject: FOS: Physical sciences

description: From an examination of ~18,000 Kepler light curves of K- and M-stars we find some 500 which exhibit rotational periods of less than 2 days. Among such stars, approximately 50 show two or more incommensurate periodicities. We discuss the tools that allow us to differentiate between rotational modulation and other types of light variations, e.g., due to pulsations or binary modulations. We find that these multiple periodicities are independent of each other and likely belong to different, but physically bound, stars. This scenario was checked directly by UKIRT and adaptive optics imaging, time-resolved Fourier transforms, and pixel-level analysis of the data. Our result is potentially important for discovering young multiple stellar systems among rapidly rotating K- and M-dwarfs.
Hubble Space Telescope: Snapshot Survey for Resolved Companions of Galactic Cepheids
Creators: name: Evans, Nancy Remage
name: Bond, Howard E.
name: Schaefer, Gail H.
name: Mason, Brian D.
name: Tingle, Evan
name: Karovska, Margarita
name: Pillitteri, Ignazio
Publisher: name: arXiv
Year: 2016
Subjects: subject: Solar and Stellar Astrophysics (astro-ph.SR)
subject: FOS: Physical sciences

description: We have conducted an imaging survey with the Hubble Space Telescope Wide Field Camera~3 (WFC3) of 70 Galactic Cepheids, typically within 1~kpc, with the aim of finding resolved physical companions. The WFC3 field typically covers the 0.1 pc area where companions are expected. In this paper, we identify 39 Cepheids having candidate companions, based on their positions in color--magnitude diagrams, and having separations $\geq$5$"$ from the Cepheids. We use follow-up observations of 14 of these candidates with XMM-Newton, and of one of them with ROSAT, to separate X-ray-active young stars (probable physical companions) from field stars (chance alignments). Our preliminary estimate, based on the optical and X-ray observations, is that only 3\% of the Cepheids in the sample have wide companions. Our survey easily detects resolved main-sequence companions as faint as spectral type K\null. Thus the fact that the two most probable companions (those of FF~Aql and RV~Sco) are earlier than type K is not simply a function of the detection limit. We find no physical companions having separations larger than 4,000~AU in the X-ray survey. Two Cepheids are exceptions in that they do have young companions at significantly larger separations ($δ$~Cep and S~Nor), but both belong to a cluster or a loose association, so our working model is that they are not gravitationally bound binary members, but rather cluster/association members. All of these properties provide constraints on both star formation and subsequent dynamical evolution. The low frequency of true physical companions at separations $>\!5"$ is confirmed by examination of the subset of the nearest Cepheids and also the density of the fields.
description: Accepted for publication in AJ
Extended Lifetime of Organic Solar Cells with New Non-Fullerene Acceptors
Creators: name: López Vicente, R.
name: Abad, J.
name: Espindola-Rodriguez, M.
name: Fernández Castro, M.
name: Andreasen, J.W.
name: Urbina, A.
Publisher: name: WIP
Year: 2020
Subjects: Perovskites and Other Non-Silicon Materials, MJs and Tandems
Organic and Dye-Sensitised

description: 37th European Photovoltaic Solar Energy Conference and Exhibition; 592-595
description: Organic bulk heterojunction solar cells have increased their power conversion efficiency (PCE) well above 10% thanks to the use of non-fullerene acceptors in binary or ternary blends in its active layer or in tandem configurations. In this work we report a lifetime study of P3HT:O-IDTBR organic solar cells on ITO-free flexible substrates and a direct comparison of glass-glass and plastic-plastic encapsulation performances, with special focus on its effect on the lifetime of the devices after degradation procedures complying with the ISOS protocols for organic photovoltaic devices. The manufactured OSCs with 1cm2 active layer have power conversion efficiencies ranging from 1.9% to 3.4% depending on encapsulant material and substrate. An exponential degradation rate has been found, with bimodal behaviour for glass and time rates of t1 = 198.0 h-1; t2 = 25.4 h-1 whereas for plastic it is a single process with t = 56.9 h-1. The longest achieved T80 lifetime is 86 h. for glassencapsulated devices under an accelerated ISOS-T3 protocol.
In-Situ Monitoring of Perovskite Thin Film Formation by High-Speed Optical Reflectance Spectroscopy
Creators: name: Camus, C.
name: Kaspari, C.
name: Rappich, J.
name: Rehermann, C.
name: Mathies, F.
name: Blank, V.
name: Unger, E.
name: Nickel, N.
Publisher: name: WIP
Year: 2020
Subjects: Perovskites and Other Non-Silicon Materials, MJs and Tandems
Perovskites

description: 37th European Photovoltaic Solar Energy Conference and Exhibition; 596-600
description: In this paper, the complete formation of various perovskite thin films during spin-coating and subsequent annealing is monitored in-situ by high-speed optical reflectance spectroscopy. Furthermore, first results for anti-solvent drip processes and the deposition of perovskite semiconductors on top of CIGS-based samples for tandem applications are presented. It is shown, that a complete “fingerprint” of the film formation process can be obtained and crucial properties like the absorption edge and its evolution during film formation can be deduced. The method also allows for real-time measurements of the amount of the remaining precursor wet-film. All this information is well-suited for tailoring film properties and identifying new paths for the optimization of performance or yield. Hence, this technology can enable and accelerate process development for perovskite thin films. This paper focuses on the experimental implementation of the in-situ measurements and presents first results on absorption edge evolution monitoring, spincoating kinetics and annealing phase transformations.
The van der Waals and Casimir energy of anisotropic atomically thin metallic films
Creators: name: Klimchitskaya, G. L.
name: Mostepanenko, V. M.
Publisher: name: arXiv
Year: 2015
Subjects: subject: Other Condensed Matter (cond-mat.other)
subject: Mesoscale and Nanoscale Physics (cond-mat.mes-hall)
subject: Quantum Physics (quant-ph)
subject: FOS: Physical sciences

description: We discuss the van der Waals (Casimir) free energies and pressures of thin metallic films, consisting from one to fifteen atomic layers, with regard to the anisotropy in their dielectric properties. Both free-standing films and films deposited on a dielectric substrate are considered. The computations are performed for a Au film and a sapphire substrate. According to our results, for free-standing Au films consisting of one and three atomic layers the respective relative error arising from the use of an isotropic (bulk) dielectric permittivity is equal to 73% and 37% for the van der Waals energy, and 70% and 35% for the pressure. We tabulate the energy and pressure van der Waals coefficients of thin Au films computed with account of their anisotropy. It is shown that the bulk permittivity of Au can be used for the films consisting of more than 30 atomic layers, i.e., more than approximately 7 nm thickness. The role of relativistic effects is also investigated and shown to be important even for the films consisting of two or three layers. The obtained results can find applications in the investigation of stability of thin films and development of novel nanoscale devices.
description: 15 pages, 1 table, 3 figures
High Bandgap Absorber for Monolithic Perovskite Silicon Tandem Solar Cells Reaching 25.1% Certified Efficiency and Ways Beyond
Creators: name: Schulze, P.S.C.
name: Bett, A.J.
name: Kabakli, O.S.
name: Winkler, K.M.
name: Mundt, L.E.
name: Gerspacher, F.M.
name: Zhang, Q.
name: Hofmann, C.L.M.
name: Bivour, M.
name: Hermle, M.
name: Glunz, S.W.
name: Hillebrecht, H.
name: Goldschmidt, J.C.
Publisher: name: WIP
Year: 2020
Subjects: Perovskites and Other Non-Silicon Materials, MJs and Tandems
Tandems

description: 37th European Photovoltaic Solar Energy Conference and Exhibition; 582-586
description: Perovskite silicon tandem solar cells (PSTSCs) can overcome the efficiency limitations of conventional single-junction silicon solar cells by reducing thermalization losses. To reach this goal, a perovskite absorber with an adapted high bandgap, good (photo-)stability, and high open-circuit voltage (VOC) is needed. First approaches tried halide mixing with high bromide content but compounds suffered from light-induced halide segregation causing voltage losses. In this work, a balanced tuning approach for [HC(NH2)2]1-xCsxPb(I1-yBry)3 perovskites is presented using reduced bromide content and compensating the bandgap effect by increasing the cesium(I) content. In that way, phase stability is reached while keeping the desired high bandgap. Moreover, surface passivation at the electron contact-perovskite interface highlights the important role of interfaces in the overall performance. [HC(NH2)2]0.75Cs0.25Pb(I0.8Br0.2)3 with an optical bandgap of ~1.69 eV is determined as the best candidate for tandem application. Implementation in monolithic PSTSCs with silicon heterojunction bottom solar cells enables high VOC of ~1836 mV with excellent photostability in a mesoscopic n-i-p configuration, and high fill factor of 80% and 25.1% certified stabilized efficiency in a planar p-i-n configuration. Heading towards higher efficiencies, a hybrid co-evaporation/spin coating route is applied for easy bandgap tuning and conformal perovskite film formation on µm-sized random pyramid-textured silicon.
Phosphorus Doped Poly-Si Passivated Contacts by LPCVD and PECVD for Industrial Large-Area Solar Cells
Creators: name: Lanterne, A.
name: Yang, J.
name: Loretz, J.C.
name: Monna, R.
name: Enjalbert, N.
name: Martel, B.
name: Benguesmia, S.
name: Lorfeuvre, C.
name: Denis, C.
name: Dubois, S.
Publisher: name: WIP
Year: 2020
Subjects: Silicon Materials and Cells
High Temperature Route for Si Cells

description: 37th European Photovoltaic Solar Energy Conference and Exhibition; 570-573
description: This work aims at developing high quality phosphorus (P) doped poly-Si/SiOx structures using massproduction compatible equipment from SEMCO-SMARTECH. The LPCVD and the PECVD techniques were both investigated for the poly-Si deposition, with ex-situ and in-situ doping for the LPCVD approach and an ex-situ doping for the PECVD path. A particular attention was paid to the thin interfacial oxide growth conditions during the formation of the n+ poly-Si/SiOx structures. The possibility to grow blister-free poly-Si layers of 170 nm thick by PECVD with a low operating frequency system was demonstrated. High surface passivation levels of the P doped poly-Si/SiOx structures were demonstrated for all the investigated approaches with iVoc above 735 mV in parralel to low contact resistivity values. The quality of the LPCVD structures was then further highlighted by their integration in high efficiency poly-Si based n-PERT solar cells. The latest optimisations of our process, based on high throuphput equipement, have led to iVoc above 725 mV and solar cell Voc of 702 mV. A maximum efficiency of 23.0% was certified with a full area measurement (244.2 cm2 ), confirming the compliancy of the LPCVD equipment with the industrialization of passivated contact solar cells.
Letter from Sir William Orpen to Lady Beatrice Glenavy (Or-45)
Creators: name: Orpen, William, Sir, 1878-1931
Publisher: name: University of Victoria Libraries
Year: 2021
Subjects: subject: Painters--Correspondence
valueUri: http://id.worldcat.org/fast/1050538
subject: Orpen, William, Sir, 1878-1931
valueUri: http://id.worldcat.org/fast/78887
subject: Glenavy, Beatrice Moss Campbell, Baroness, 1883-1970
valueUri: http://id.worldcat.org/fast/2012667
subject: Painters--Biography
valueUri: http://id.worldcat.org/fast/1050534

description: One of a collection of 36 letters all illustrated with ink or pencil sketches. Most are addressed to "Bridgit" from "Dijit". Orpen writing to Beatrice asking her if she is still seeing Pege, and that he can lend her money if she needs it. Sketch of Orpen getting "blown into the sea".
Silicon-Based Monolithic Triple-Junction Solar Cells with Conversion Efficiency >34%
Creators: name: Müller, R.
name: Schygulla, P.
name: Lackner, D.
name: Höhn, O.
name: Hauser, H.
name: Richter, A.
name: Fell, A.
name: Bläsi, B.
name: Predan, F.
name: Benick, J.
name: Hermle, M.
name: Dimroth, F.
name: Glunz, S.W.
Publisher: name: WIP
Year: 2020
Subjects: Perovskites and Other Non-Silicon Materials, MJs and Tandems
Tandems

description: 37th European Photovoltaic Solar Energy Conference and Exhibition; 574-578
description: Triple-junction solar cells with top cells made from III-V compound semiconductors on a silicon bottom cell show conversion efficiencies beyond the theoretical limit of single-junction devices, so this is one of the promising technologies for terrestrial photovoltaics. In this work, a III-V//Si tandem device with 34.5% efficiency is presented and further developments are discussed. A detailed investigation of the silicon bottom cell revealed, that with optimum wafer resistivity (~1 Ω cm) and low-temperature passivation of the cell perimeter, the perimeter losses can be reduced to ~0.2%abs. This corresponds to an efficiency gain of up to 0.8%abs for the current devices.
Analysis and Optimization of Perovskite-Silicon Tandem Solar Cells by Full Optoelectronic Simulation
Creators: name: Aeberhard, U.
name: Schiller, A.
name: Blülle, B.
name: Ruhstaller, B.
Publisher: name: WIP
Year: 2020
Subjects: Perovskites and Other Non-Silicon Materials, MJs and Tandems
Tandems

description: 37th European Photovoltaic Solar Energy Conference and Exhibition; 579-581
description: We present a comprehensive and enabling approach to the modeling of perovskite-silicon tandem solar cell device characteristics. The framework is based on 1D opto-electronic device simulation at steady state and includes specific features of the perovskite materials such as mobile ions as well as the explicit consideration of the recombination junction that is key to the simulation of tandem devices. As a further salient feature, advanced optimization algorithms are used for both optical and full opto-electronic device optimization.