@article{FischerWinterFelisattietal.2021, author = {Fischer, Martin H. and Winter, Bodo and Felisatti, Arianna and Myachykov, Andriy and Jeglinski-Mende, Melinda A. and Shaki, Samuel}, title = {More Instructions Make Fewer Subtractions}, series = {Frontiers in Psychology}, volume = {12}, journal = {Frontiers in Psychology}, publisher = {Frontiers Media SA}, address = {Lausanne, Schweiz}, issn = {1664-1078}, doi = {10.3389/fpsyg.2021.720616}, pages = {1 -- 3}, year = {2021}, abstract = {Research on problem solving offers insights into how humans process task-related information and which strategies they use (Newell and Simon, 1972; {\"O}llinger et al., 2014). Problem solving can be defined as the search for possible changes in one's mind (Kahneman, 2003). In a recent study, Adams et al. (2021) assessed whether the predominant problem solving strategy when making changes involves adding or subtracting elements. In order to do this, they used several examples of simple problems, such as editing text or making visual patterns symmetrical, either in naturalistic settings or on-line. The essence of the authors' findings is a strong preference to add rather than subtract elements across a diverse range of problems, including the stabilizing of artifacts, creating symmetrical patterns, or editing texts. More specifically, they succeeded in demonstrating that "participants were less likely to identify advantageous subtractive changes when the task did not (vs. did) cue them to consider subtraction, when they had only one opportunity (vs. several) to recognize the shortcomings of an additive search strategy or when they were under a higher (vs. lower) cognitive load" (Adams et al., 2021, p. 258). Addition and subtraction are generally defined as de-contextualized mathematical operations using abstract symbols (Russell, 1903/1938). Nevertheless, understanding of both symbols and operations is informed by everyday activities, such as making or breaking objects (Lakoff and N{\´u}{\~n}ez, 2000; Fischer and Shaki, 2018). The universal attribution of "addition bias" or "subtraction neglect" to problem solving activities is perhaps a convenient shorthand but it overlooks influential framing effects beyond those already acknowledged in the report and the accompanying commentary (Meyvis and Yoon, 2021). Most importantly, while Adams et al.'s study addresses an important issue, their very method of verbally instructing participants, together with lack of control over several known biases, might render their findings less than conclusive. Below, we discuss our concerns that emerged from the identified biases, namely those regarding the instructions and the experimental materials. Moreover, we refer to research from mathematical cognition that provides new insights into Adams et al.'s findings.}, language = {en} } @article{StolterfohtCaprioglioWolffetal.2019, author = {Stolterfoht, Martin and Caprioglio, Pietro and Wolff, Christian Michael and Marquez, Jose A. and Nordmann, Joleik and Zhang, Shanshan and Rothhardt, Daniel and H{\"o}rmann, Ulrich and Amir, Yohai and Redinger, Alex and Kegelmann, Lukas and Zu, Fengshuo and Albrecht, Steve and Koch, Norbert and Kirchartz, Thomas and Saliba, Michael and Unold, Thomas and Neher, Dieter}, title = {The impact of energy alignment and interfacial recombination on the internal and external open-circuit voltage of perovskite solar cells}, series = {Energy \& environmental science}, volume = {12}, journal = {Energy \& environmental science}, number = {9}, publisher = {Royal Society of Chemistry}, address = {Cambridge}, issn = {1754-5692}, doi = {10.1039/c9ee02020a}, pages = {2778 -- 2788}, year = {2019}, abstract = {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.}, language = {en} } @article{CaprioglioZuWolffetal.2019, author = {Caprioglio, Pietro and Zu, Fengshuo and Wolff, Christian Michael and Prieto, Jose A. Marquez and Stolterfoht, Martin and Becker, Pascal and Koch, Norbert and Unold, Thomas and Rech, Bernd and Albrecht, Steve and Neher, Dieter}, title = {High open circuit voltages in pin-type perovskite solar cells through strontium addition}, series = {Sustainable Energy \& Fuels}, volume = {3}, journal = {Sustainable Energy \& Fuels}, number = {2}, publisher = {Royal Society of Chemistry}, address = {Cambridge}, issn = {2398-4902}, doi = {10.1039/c8se00509e}, pages = {550 -- 563}, year = {2019}, abstract = {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.}, language = {en} } @article{KirchartzMarquezStolterfohtetal.2020, author = {Kirchartz, Thomas and M{\´a}rquez, Jos{\´e} A. and Stolterfoht, Martin and Unold, Thomas}, title = {Photoluminescence-based characterization of halide perovskites for photovoltaics}, series = {Advanced Energy Materials}, volume = {10}, journal = {Advanced Energy Materials}, number = {26}, publisher = {Wiley}, address = {Weinheim}, issn = {1614-6832}, doi = {10.1002/aenm.201904134}, pages = {1 -- 21}, year = {2020}, abstract = {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.}, language = {en} } @misc{KirchartzMarquezStolterfohtetal.2020, author = {Kirchartz, Thomas and M{\´a}rquez, Jos{\´e} A. and Stolterfoht, Martin and Unold, Thomas}, title = {Photoluminescence-based characterization of halide perovskites for photovoltaics}, series = {Zweitver{\"o}ffentlichungen der Universit{\"a}t Potsdam : Mathematisch-Naturwissenschaftliche Reihe}, journal = {Zweitver{\"o}ffentlichungen der Universit{\"a}t Potsdam : Mathematisch-Naturwissenschaftliche Reihe}, number = {26}, issn = {1866-8372}, doi = {10.25932/publishup-51970}, url = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus4-519702}, pages = {23}, year = {2020}, abstract = {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.}, language = {en} } @article{StolterfohtWolffMarquezetal.2018, author = {Stolterfoht, Martin and Wolff, Christian Michael and Marquez, Jose A. and Zhang, Shanshan and Hages, Charles J. and Rothhardt, Daniel and Albrecht, Steve and Burn, Paul L. and Meredith, Paul and Unold, Thomas and Neher, Dieter}, title = {Visualization and suppression of interfacial recombination for high-efficiency large-area pin perovskite solar cells}, series = {Nature Energy}, volume = {3}, journal = {Nature Energy}, number = {10}, publisher = {Nature Publ. Group}, address = {London}, issn = {2058-7546}, doi = {10.1038/s41560-018-0219-8}, pages = {847 -- 854}, year = {2018}, abstract = {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\%).}, language = {en} } @article{RamosLariosToalaRodriguezGonzalezetal.2022, author = {Ramos-Larios, Gerardo and Toala, Jes{\´u}s Alberto and Rodriguez-Gonzalez, Janis B. and Guerrero, Martin A. and Gomez-Gonzalez, V{\´i}ctor Mauricio Alfonso}, title = {Rings and arcs around evolved stars - III. Physical conditions of the ring-like structures in the planetary nebula IC 4406 revealed by MUSE}, series = {Monthly notices of the Royal Astronomical Society}, volume = {513}, journal = {Monthly notices of the Royal Astronomical Society}, number = {2}, publisher = {Oxford Univ. Press}, address = {Oxford}, issn = {0035-8711}, doi = {10.1093/mnras/stac605}, pages = {2862 -- 2868}, year = {2022}, abstract = {We present the analysis of Very Large Telescope Multi Unit Spectroscopic Explorer (MUSE) observations of the planetary nebula (PN) IC 4406. MUSE images in key emission lines are used to unveil the presence of at least five ring-like structures north and south of the main nebula of IC4406. MUSE spectra are extracted from the rings to unambiguously assess for the first time in a PN their physical conditions, electron density (n(e)), and temperature (T-e). The rings are found to have similar T-e as the rim of the main nebula, but smaller n(e). Ratios between different ionic species suggest that the rings of IC4406 have a lower ionization state than the main cavity, in contrast to what was suggested for the rings in NGC 6543, the Cat's Eye Nebula.}, language = {en} } @article{TrauthBergnerFoersteretal.2015, author = {Trauth, Martin H. and Bergner, Andreas G. N. and Foerster, Verena and Junginger, Annett and Maslin, Mark A. and Sch{\"a}bitz, Frank}, title = {Episodes of environmental stability versus instability in Late Cenozoic lake records of Eastern Africa}, series = {Journal of human evolution}, volume = {87}, journal = {Journal of human evolution}, publisher = {Elsevier}, address = {London}, issn = {0047-2484}, doi = {10.1016/j.jhevol.2015.03.011}, pages = {21 -- 31}, year = {2015}, abstract = {Episodes of environmental stability and instability may be equally important for African hominin speciation, dispersal, and cultural innovation. Three examples of a change from stable to unstable environmental conditions are presented on three different time scales: (1) the Mid Holocene (MH) wet dry transition in the Chew Bahir basin (Southern Ethiopian Rift; between 11 ka and 4 ka), (2) the MIS 5-4 transition in the Naivasha basin (Central Kenya Rift; between 160 ka and 50 ka), and (3) the Early Mid Pleistocene Transition (EMPT) in the Olorgesailie basin (Southern Kenya Rift; between 1.25 Ma and 0.4 Ma). A probabilistic age modeling technique is used to determine the timing of these transitions, taking into account possible abrupt changes in the sedimentation rate including episodes of no deposition (hiatuses). Interestingly, the stable-unstable conditions identified in the three records are always associated with an orbitally-induced decrease of insolation: the descending portion of the 800 kyr cycle during the EMPT, declining eccentricity after the 115 ka maximum at the MIS 5-4 transition, and after similar to 10 ka. This observation contributes to an evidence-based discussion of the possible mechanisms causing the switching between environmental stability and instability in Eastern Africa at three different orbital time scales (10,000 to 1,000,000 years) during the Cenozoic. This in turn may lead to great insights into the environmental changes occurring at the same time as hominin speciation, brain expansion, dispersal out of Africa, and cultural innovations and may provide key evidence to build new hypotheses regarding the causes of early human evolution. (C) 2015 Elsevier Ltd. All rights reserved.}, language = {en} } @article{TrauthAsratDuesingetal.2019, author = {Trauth, Martin H. and Asrat, Asfawossen and D{\"u}sing, Walter and Foerster, Verena and Kr{\"a}mer, K. Hauke and Marwan, Norbert and Maslin, Mark A. and Sch{\"a}bitz, Frank}, title = {Classifying past climate change in the Chew Bahir basin, southern Ethiopia, using recurrence quantification analysis}, series = {Climate dynamics : observational, theoretical and computational research on the climate system}, volume = {53}, journal = {Climate dynamics : observational, theoretical and computational research on the climate system}, number = {5-6}, publisher = {Springer}, address = {New York}, issn = {0930-7575}, doi = {10.1007/s00382-019-04641-3}, pages = {2557 -- 2572}, year = {2019}, abstract = {The Chew Bahir Drilling Project (CBDP) aims to test possible linkages between climate and evolution in Africa through the analysis of sediment cores that have recorded environmental changes in the Chew Bahir basin. In this statistical project we consider the Chew Bahir palaeolake to be a dynamical system consisting of interactions between its different components, such as the waterbody, the sediment beneath lake, and the organisms living within and around the lake. Recurrence is a common feature of such dynamical systems, with recurring patterns in the state of the system reflecting typical influences. Identifying and defining these influences contributes significantly to our understanding of the dynamics of the system. Different recurring changes in precipitation, evaporation, and wind speed in the Chew Bahir basin could result in similar (but not identical) conditions in the lake (e.g., depth and area of the lake, alkalinity and salinity of the lake water, species assemblages in the water body, and diagenesis in the sediments). Recurrence plots (RPs) are graphic displays of such recurring states within a system. Measures of complexity were subsequently introduced to complement the visual inspection of recurrence plots, and provide quantitative descriptions for use in recurrence quantification analysis (RQA). We present and discuss herein results from an RQA on the environmental record from six short (< 17 m) sediment cores collected during the CBDP, spanning the last 45 kyrs. The different types of variability and transitions in these records were classified to improve our understanding of the response of the biosphere to climate change, and especially the response of humans in the area.}, language = {en} } @article{SporbertJakubkaBucheretal.2022, author = {Sporbert, Maria and Jakubka, Desiree and Bucher, Solveig Franziska and Hensen, Isabell and Freiberg, Martin and Heubach, Katja and K{\"o}nig, Andreas and Nordt, Birgit and Plos, Carolin and Blinova, Ilona and Bonn, Aletta and Knickmann, Barbara and Koubek, Tom{\´a}š and Linst{\"a}dter, Anja and Maškov{\´a}, Tereza and Primack, Richard B. and Rosche, Christoph and Shah, Manzoor A. and Stevens, Albert-Dieter and Tielb{\"o}rger, Katja and Tr{\"a}ger, Sabrina and Wirth, Christian and R{\"o}mermann, Christine}, title = {Functional traits influence patterns in vegetative and reproductive plant phenology - a multi-botanical garden study}, series = {New phytologist}, volume = {235}, journal = {New phytologist}, number = {6}, publisher = {Wiley}, address = {Hoboken}, issn = {0028-646X}, doi = {10.1111/nph.18345}, pages = {2199 -- 2210}, year = {2022}, abstract = {Phenology has emerged as key indicator of the biological impacts of climate change, yet the role of functional traits constraining variation in herbaceous species' phenology has received little attention. Botanical gardens are ideal places in which to investigate large numbers of species growing under common climate conditions. We ask whether interspecific variation in plant phenology is influenced by differences in functional traits. We recorded onset, end, duration and intensity of initial growth, leafing out, leaf senescence, flowering and fruiting for 212 species across five botanical gardens in Germany. We measured functional traits, including plant height, absolute and specific leaf area, leaf dry matter content, leaf carbon and nitrogen content and seed mass and accounted for species' relatedness. Closely related species showed greater similarities in timing of phenological events than expected by chance, but species' traits had a high degree of explanatory power, pointing to paramount importance of species' life-history strategies. Taller plants showed later timing of initial growth, and flowered, fruited and underwent leaf senescence later. Large-leaved species had shorter flowering and fruiting durations. Taller, large-leaved species differ in their phenology and are more competitive than smaller, small-leaved species. We assume climate warming will change plant communities' competitive hierarchies with consequences for biodiversity.}, language = {en} }