@misc{WolffBrand2016, author = {Wolff, Wanja and Brand, Ralf}, title = {Editorial: using substances to enhance performance}, series = {Postprints der Universit{\"a}t Potsdam : Humanwissenschaftliche Reihe}, journal = {Postprints der Universit{\"a}t Potsdam : Humanwissenschaftliche Reihe}, number = {443}, url = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus4-407274}, pages = {2}, year = {2016}, language = {en} } @misc{WolffBrand2016, author = {Wolff, Wanja and Brand, Ralf}, title = {Editorial: Using Substances to Enhance Performance: A Psychology of Neuroenhancement}, series = {Frontiers in psychology}, volume = {7}, journal = {Frontiers in psychology}, publisher = {Frontiers Research Foundation}, address = {Lausanne}, issn = {1664-1078}, doi = {10.3389/fpsyg.2016.01741}, pages = {2}, year = {2016}, language = {en} } @misc{WolffBrand2013, author = {Wolff, Wanja and Brand, Ralf}, title = {Subjective stressors in school and their relation to neuroenhancement}, url = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus4-401131}, pages = {6}, year = {2013}, abstract = {Background: The use of psychoactive substances to neuroenhance cognitive performance is prevalent. Neuroenhancement (NE) in everyday life and doping in sport might rest on similar attitudinal representations, and both behaviors can be theoretically modeled by comparable means-to-end relations (substance-performance). A behavioral (not substance-based) definition of NE is proposed, with assumed functionality as its core component. It is empirically tested whether different NE variants (lifestyle drug, prescription drug, and illicit substance) can be regressed to school stressors. Findings: Participants were 519 students (25.8 +/- 8.4 years old, 73.1\% female). Logistic regressions indicate that a modified doping attitude scale can predict all three NE variants. Multiple NE substance abuse was frequent. Overwhelming demands in school were associated with lifestyle and prescription drug NE. Conclusions: Researchers should be sensitive for probable structural similarities between enhancement in everyday life and sport and systematically explore where findings from one domain can be adapted for the other. Policy makers should be aware that students might misperceive NE as an acceptable means of coping with stress in school, and help to form societal sensitivity for the topic of NE among our younger ones in general.}, language = {en} } @article{LeCorreStolterfohtPerdigonToroetal.2019, author = {Le Corre, Vincent M. and Stolterfoht, Martin and Perdigon Toro, Lorena and Feuerstein, Markus and Wolff, Christian Michael and Gil-Escrig, Lidon and Bolink, Henk J. and Neher, Dieter and Koster, L. Jan Anton}, title = {Charge Transport Layers Limiting the Efficiency of Perovskite Solar Cells: How To Optimize Conductivity, Doping, and Thickness}, series = {ACS Applied Energy Materials}, volume = {2}, journal = {ACS Applied Energy Materials}, number = {9}, publisher = {American Chemical Society}, address = {Washington}, issn = {2574-0962}, doi = {10.1021/acsaem.9b00856}, pages = {6280 -- 6287}, year = {2019}, abstract = {Perovskite solar cells (PSCs) are one of the main research topics of the photovoltaic community; with efficiencies now reaching up to 24\%, PSCs are on the way to catching up with classical inorganic solar cells. However, PSCs have not yet reached their full potential. In fact, their efficiency is still limited by nonradiative recombination, mainly via trap-states and by losses due to the poor transport properties of the commonly used transport layers (TLs). Indeed, state-of-the-art TLs (especially if organic) suffer from rather low mobilities, typically within 10(-5) and 10(-2) cm(-2) V-1 s(-1), when compared to the high mobilities, 1-10 cm(-2) V-1 s(-1), measured for perovskites. This work presents a comprehensive analysis of the effect of the mobility, thickness, and doping density of the transport layers based on combined experimental and modeling results of two sets of devices made of a solution-processed high-performing triple-cation (PCE approximate to 20\%). The results are also cross-checked on vacuum-processed MAPbI(3) devices. From this analysis, general guidelines on how to optimize a TL are introduced and especially a new and simple formula to easily calculate the amount of doping necessary to counterbalance the low mobility of the TLs.}, language = {en} } @misc{LazurasBarkoukisLoukovitisetal.2018, author = {Lazuras, Lambros and Barkoukis, Vassilis and Loukovitis, Andreas and Brand, Ralf and Hudson, Andy and Mallia, Luca and Michaelides, Michalis and Muzi, Milena and Petroczi, Andrea and Zelli, Arnaldo}, title = {Corrigendum: "I Want It All, and I Want It Now": Lifetime Prevalence and Reasons for Using and Abstaining from Controlled Performance and Appearance Enhancing Substances (PAES) among Young Exercisers and Amateur Athletes in Five European Countries (Frontiers in psychology. - 8 (2017), 717.)}, series = {Frontiers in psychology}, volume = {9}, journal = {Frontiers in psychology}, publisher = {Frontiers Research Foundation}, address = {Lausanne}, issn = {1664-1078}, doi = {10.3389/fpsyg.2018.01162}, pages = {4}, year = {2018}, language = {en} } @article{LazurasBarkoukisLoukovitisetal.2017, author = {Lazuras, Lambros and Barkoukis, Vassilis and Loukovitis, Andreas and Brand, Ralf and Hudson, Andy and Mallia, Luca and Michaelides, Michalis and Muzi, Milena and Petroczi, Andrea and Zelli, Arnaldo}, title = {"I Want It All, and I Want It Now": Lifetime Prevalence and Reasons for Using and Abstaining from Controlled Performance and Appearance Enhancing Substances (PAES) among Young Exercisers and Amateur Athletes in Five European Countries}, series = {Frontiers in psychology}, volume = {8}, journal = {Frontiers in psychology}, publisher = {Frontiers Research Foundation}, address = {Lausanne}, issn = {1664-1078}, doi = {10.3389/fpsyg.2017.00717}, pages = {9}, year = {2017}, abstract = {Doping use in recreational sports is an emerging issue that has received limited attention so far in the psychological literature. The present study assessed the lifetime prevalence of controlled performance and appearance enhancing substances ( PAES), and used behavioral reasoning theory to identify the reasons for using and for avoiding using controlled PAES in young exercisers across five European countries, in the context of the "SAFE YOU" Project. Participants were 915 young amateur athletes and exercisers (M = 21.62; SD = 2.62) from Cyprus, Germany, Greece, Italy, and UK who completed an anonymous questionnaire that included measures of self-reported use of controlled PAES, as well as reasons for using and not using controlled PAES. The results of the descriptive analyses demonstrated that almost one out five exercisers in the sample had a previous experience with controlled PAES. Higher prevalence rates were found in Greece and Cyprus and lower in Italy. The most frequently reported reasons for using controlled PAES included achieving the desired results faster; pushing the self to the (physical) limits; and recovering faster after exercise/training. Furthermore, the most frequently reported reasons for not using controlled PAES involved worry about any possible adverse health effects; not feeling the need for using them; and wanting to see what can be achieved naturally without using any controlled PAES. The findings of the present study indicate that the use of controlled PAES is fast becoming a crisis in amateur sports and exercise settings and highlight the need for preventive action and concerted anti-doping education efforts.}, language = {en} } @article{GhaniOpitzPingeletal.2015, author = {Ghani, Fatemeh and Opitz, Andreas and Pingel, Patrick and Heimel, Georg and Salzmann, Ingo and Frisch, Johannes and Neher, Dieter and Tsami, Argiri and Scherf, Ullrich and Koch, Norbert}, title = {Charge Transfer in and Conductivity of Molecularly Doped Thiophene-Based Copolymers}, series = {Journal of polymer science : B, Polymer physics}, volume = {53}, journal = {Journal of polymer science : B, Polymer physics}, number = {1}, publisher = {Wiley-Blackwell}, address = {Hoboken}, issn = {0887-6266}, doi = {10.1002/polb.23631}, pages = {58 -- 63}, year = {2015}, abstract = {The electrical conductivity of organic semiconductors can be enhanced by orders of magnitude via doping with strong molecular electron acceptors or donors. Ground-state integer charge transfer and charge-transfer complex formation between organic semiconductors and molecular dopants have been suggested as the microscopic mechanisms causing these profound changes in electrical materials properties. Here, we study charge-transfer interactions between the common molecular p-dopant 2,3,5,6-tetrafluoro-7,7,8,8-tetracyanoquinodimethane and a systematic series of thiophene-based copolymers by a combination of spectroscopic techniques and electrical measurements. Subtle variations in chemical structure are seen to significantly impact the nature of the charge-transfer species and the efficiency of the doping process, underlining the need for a more detailed understanding of the microscopic doping mechanism in organic semiconductors to reliably guide targeted chemical design.}, language = {en} } @article{BrandKoch2016, author = {Brand, Ralf and Koch, Helen}, title = {Using Caffeine Pills for Performance Enhancement. An Experimental Study Neuroenhancements}, series = {Frontiers in psychology}, volume = {7}, journal = {Frontiers in psychology}, publisher = {Frontiers Research Foundation}, address = {Lausanne}, issn = {1664-1078}, doi = {10.3389/fpsyg.2016.00101}, pages = {11}, year = {2016}, abstract = {Recent research has indicated that university students sometimes use caffeine pills for neuroenhancement (NE; non-medical use of psychoactive substances or technology to produce a subjective enhancement in psychological functioning and experience), especially during exam preparation. In our factorial survey experiment, we manipulated the evidence participants were given about the prevalence of NE amongst peers and measured the resulting effects on the psychological predictors included in the Prototype-Willingness Model of risk behavior. Two hundred and thirty-one university students were randomized to a high prevalence condition (read faked research results overstating usage of caffeine pills amongst peers by a factor of 5; 50\%), low prevalence condition (half the estimated prevalence; 5\%) or control condition (no information about peer prevalence). Structural equation modeling confirmed that our participants' willingness and intention to use caffeine pills in the next exam period could be explained by their past use of neuroenhancers, attitude to NE and subjective norm about use of caffeine pills whilst image of the typical user was a much less important factor. Provision of inaccurate information about prevalence reduced the predictive power of attitude with respect to willingness by 40-45\%. This may be because receiving information about peer prevalence which does not fit with their perception of the social norm causes people to question their attitude. Prevalence information might exert a deterrent effect on NE via the attitude-willingness association. We argue that research into NE and deterrence of associated risk behaviors should be informed by psychological theory.}, language = {en} } @article{BrandKoch2016, author = {Brand, Ralf and Koch, Helen}, title = {Using Caffeine Pills for Performance Enhancement}, series = {Frontiers in psychology}, volume = {7}, journal = {Frontiers in psychology}, publisher = {Frontiers Research Foundation}, address = {Lausanne}, issn = {1664-1078}, doi = {10.3389/fpsyg.2016.00101}, pages = {1 -- 11}, year = {2016}, abstract = {Recent research has indicated that university students sometimes use caffeine pills for neuroenhancement (NE; non-medical use of psychoactive substances or technology to produce a subjective enhancement in psychological functioning and experience), especially during exam preparation. In our factorial survey experiment, we manipulated the evidence participants were given about the prevalence of NE amongst peers and measured the resulting effects on the psychological predictors included in the Prototype-Willingness Model of risk behavior. Two hundred and thirty-one university students were randomized to a high prevalence condition (read faked research results overstating usage of caffeine pills amongst peers by a factor of 5; 50\%), low prevalence condition (half the estimated prevalence; 5\%) or control condition (no information about peer prevalence). Structural equation modeling confirmed that our participants' willingness and intention to use caffeine pills in the next exam period could be explained by their past use of neuroenhancers, attitude to NE and subjective norm about use of caffeine pills whilst image of the typical user was a much less important factor. Provision of inaccurate information about prevalence reduced the predictive power of attitude with respect to willingness by 40-45\%. This may be because receiving information about peer prevalence which does not fit with their perception of the social norm causes people to question their attitude. Prevalence information might exert a deterrent effect on NE via the attitude-willingness association. We argue that research into NE and deterrence of associated risk behaviors should be informed by psychological theory.}, language = {en} } @misc{BrandKoch2016, author = {Brand, Ralf and Koch, Helen}, title = {Using Caffeine Pills for Performance Enhancement}, url = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus4-90506}, year = {2016}, abstract = {Recent research has indicated that university students sometimes use caffeine pills for neuroenhancement (NE; non-medical use of psychoactive substances or technology to produce a subjective enhancement in psychological functioning and experience), especially during exam preparation. In our factorial survey experiment, we manipulated the evidence participants were given about the prevalence of NE amongst peers and measured the resulting effects on the psychological predictors included in the Prototype-Willingness Model of risk behavior. Two hundred and thirty-one university students were randomized to a high prevalence condition (read faked research results overstating usage of caffeine pills amongst peers by a factor of 5; 50\%), low prevalence condition (half the estimated prevalence; 5\%) or control condition (no information about peer prevalence). Structural equation modeling confirmed that our participants' willingness and intention to use caffeine pills in the next exam period could be explained by their past use of neuroenhancers, attitude to NE and subjective norm about use of caffeine pills whilst image of the typical user was a much less important factor. Provision of inaccurate information about prevalence reduced the predictive power of attitude with respect to willingness by 40-45\%. This may be because receiving information about peer prevalence which does not fit with their perception of the social norm causes people to question their attitude. Prevalence information might exert a deterrent effect on NE via the attitude-willingness association. We argue that research into NE and deterrence of associated risk behaviors should be informed by psychological theory.}, language = {en} } @phdthesis{Berthold2017, author = {Berthold, Thomas}, title = {Tannine f{\"u}r nachhaltige und funktionale Kohlenstoffmaterialien}, url = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus4-407564}, school = {Universit{\"a}t Potsdam}, pages = {85, xlvi}, year = {2017}, abstract = {In Zeiten eines sich schnell {\"a}ndernden und vielseitigen Energiemarktes m{\"u}ssen Kohlenstoffmaterialien f{\"u}r verschiedene Anforderungen einsetzbar sein. Dies erfordert flexibel synthetisierbare Kohlenstoffmaterialien bevorzugt aus g{\"u}nstigen und nachhaltigen Kohlenstoffquellen. Es ist allerdings nicht leicht Vorl{\"a}uferverbindungen auszumachen, welche sich einerseits f{\"u}r verschiedene Herstellungsverfahren eignen und deren Kohlenstoffprodukte andererseits in spezifischen Eigenschaften, wie der Struktur, des Stickstoffanteils, der Oberfl{\"a}che und der Porengr{\"o}ßen, eingestellt werden k{\"o}nnen. In diesem Zusammenhang k{\"o}nnen nat{\"u}rliche Polyphenole, etwa {\"u}bersch{\"u}ssige Tannine aus der Weinproduktion, eine neue Welt zu hoch funktionalen und vielseitig einstellbaren Kohlenstoffmaterialien mit hohen Ausbeuten {\"o}ffnen. Das Hauptziel dieser vorliegenden Thesis war es neue funktionale, einstellbare und skalierbare nanostrukturierte Kohlenstoffmaterialien aus Tanninen (insbesondere Tannins{\"a}ure) f{\"u}r unterschiedliche elektrochemische Zwecke zu synthetisieren und zu charakterisieren. Erm{\"o}glicht wurde dies durch unterschiedliche synthetische Herangehensweisen, wie etwa der polymeren Strukturdirektion, dem ionothermalen Templatieren und der weichen Templatierung. An Stelle des weitl{\"a}ufig gebr{\"a}uchlichen, aber kanzerogenen Vernetzungsagens Formaldehyd wurden bei den vorgestellten Synthesen Harnstoff und Thioharnstoff gew{\"a}hlt, um zugleich die synthetisierten Kohlenmaterialien variabel dotieren zu k{\"o}nnen. Daher wurden im ersten Teil der Arbeit die Wechselwirkungen, Reaktionen und thermischen Verhaltensweisen von Tannins{\"a}ure und Mixturen von Tannins{\"a}ure und Harnstoff bzw. Thioharnstoff untersucht, um daraus wichtige Erkenntnisse f{\"u}r die verschiedenen Kohlenstoffsynthesen zu gewinnen. Durch die Verwendung eines polymeren Strukturierungsagenz Pluronic P123 konnten in einer ersten Kohlenstoffsynthese nachhaltige und dotierbare Kohlenstoffpartikel mit Durchmessern im Nanometerbereich aus Tannins{\"a}ure und Harnstoff hergestellt werden. Es konnte dabei gezeigt werden, dass durch die Modifikation der verschiedenen Syntheseparameter die Kohlenstoffnanopartikel gem{\"a}ß ihres gemittelten Partikeldurchmessers, ihrer BET-Oberfl{\"a}che, ihrer Komposition, ihrer Leitf{\"a}higkeit und ihrer chemischen Stabilit{\"a}t einstellbar sind. Dies er{\"o}ffnete die M{\"o}glichkeit diese Kohlenstoffpartikel als alternatives und nachhaltiges Rußmaterial einzusetzen. Weiterhin war es durch die ionothermale Templatierung m{\"o}glich por{\"o}se, dotierte und kontrollierbare Kohlenstoffpartikel mit hohen spezifischen Oberfl{\"a}chen aus den gew{\"a}hlten Pr{\"a}kursorverbindungen zu synthetisieren, die sich f{\"u}r den Einsatz in Superkondensatoren eignen. Auf diesen Erkenntnissen aufbauend konnten mittels der Rotationsbeschichtung por{\"o}se binderfreie und strukturierte Kohlenstofffilme synthetisiert werden, die eine spinodale Struktur aufwiesen. Anhand der Modifikation der Stamml{\"o}sungskonzentration, der Rotationsgeschwindigkeit und der verwendeten Substrate konnten die Filmdicke (100-1000 nm), die Morphologie und Gesamtoberfl{\"a}che gezielt beeinflusst werden. Die erweiterte elektrochemische Analyse zeigte außerdem ein sehr gut zug{\"a}ngliches Porensystem der por{\"o}sen Kohlenstofffilme. Allumfassend konnten demnach verschiedene Synthesewege f{\"u}r Kohlenstoffmaterialien aus Tanninen aufgezeigt werden, die verschiedenartig strukturiert und kontrolliert werden k{\"o}nnen und sich f{\"u}r diverse Anwendungsgebiete eignen.}, language = {de} }