Stephan Roth

Prof. Stephan Roth

Deutsches Elektronen‐Synchrotron (DESY), Hamburg, Germany & KTH Royal Institute of Technology, Stockholm, Sweden

Research Focus & Metrics

Academic Career Length

32Years (1995-Present)

(Calculated once Scilit publication data is synced: current year − year of first publication + 1)

Representative Publications

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30 September 2014 in Journal of Applied Crystallography
Verified
Journal Article
Open access
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GBGunthard Benecke
Gunthard Benecke
WWWolfgang Wagermaier
Wolfgang Wagermaier
CLChenghao Li
Chenghao Li
MSMatthias Schwartzkopf
Matthias Schwartzkopf
GFGero Flucke
Gero Flucke
Peter FratzlPeter Fratzl
Peter Fratzl
X-ray scattering experiments at synchrotron sources are characterized by large and constantly increasing amounts of data. The great number of files generated during a synchrotron experiment is often a limiting factor in the analysis of the data, since appropriate software is rarely available to perform fast and tailored data processing. Furthermore, it is often necessary to perform online data reduction and analysis during the experiment in order to interactively optimize experimental design. This article presents an open-source software package developed to process large amounts of data from synchrotron scattering experiments. These data reduction processes involve calibration and correction of raw data, one- or two-dimensional integration, as well as fitting and further analysis of the data, including the extraction of certain parameters. The software,DPDAK(directly programmable data analysis kit), is based on a plug-in structure and allows individual extension in accordance with the requirements of the user. The article demonstrates the use ofDPDAKfor on- and offline analysis of scanning small-angle X-ray scattering (SAXS) data on biological samples and microfluidic systems, as well as for a comprehensive analysis of grazing-incidence SAXS data. In addition to a comparison with existing software packages, the structure ofDPDAKand the possibilities and limitations are discussed.

18 October 2021 in Nature Energy
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Journal Article
Closed access
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RGRenjun Guo
Renjun Guo
DHDan Han
Dan Han
Wei ChenWei Chen
Wei Chen
Linjie DaiLinjie Dai
Linjie Dai
KJKangyu Ji
Kangyu Ji
Peter Muller-BuschbaumPeter Muller-Buschbaum
Peter Muller-Buschbaum

20 November 2019 in Journal of the American Chemical Society
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Journal Article
Closed access
FZFuguo Zhang
Fuguo Zhang
ZYZhaoyang Yao
Zhaoyang Yao
YGYaxiao Guo
Yaxiao Guo
YLYuanyuan Li
Yuanyuan Li
JBJan Bergstrand
Jan Bergstrand
LSLicheng Sun
Licheng Sun

12 June 2020 in Energy & Environmental Science
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Journal Article
Closed access
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BLBaojun Lin
Baojun Lin
XZXiaobo Zhou
Xiaobo Zhou
HZHeng Zhao
Heng Zhao
JYJian Yuan
Jian Yuan
KZKe Zhou
Ke Zhou
WMWei Ma
Wei Ma
Slot-die coating being compatible with the roll-to-roll technique has been regarded as a promising tool for upscaling the manufacturing of organic solar cells (OSCs). However, there has been a significant gap between the efficiencies of the state-of-the-art spin-coated devices and the scalable processed devices. The active layer morphology is crucial to achieve high efficiency in OSCs, which depends on the conditions of film fabrication. To figure out and optimize the slot-die coating process, a deeper understanding of the film formation kinetics is important. Herein, in situ measurements of the slot-die coating process based on the PM7:IT4F system are demonstrated to illustrate the aggregation and crystallization evolution at various die temperatures and substrate temperatures. OSCs with a high power conversion efficiency of 13.2% are achieved at 60 °C die temperature/60 °C substrate temperature due to the improved exciton dissociation, charge transport and suppressed non-radiative charge recombination. The optimized morphology is attributed to the balanced polymer pre-aggregation and small molecule crystallization kinetics. The unsuitable die temperature leads to overlarge phase separation and consequently inefficient exciton dissociation while the improper substrate temperature results in weak crystallization and the following shrunken carrier lifetime with strong non-radiative combination. This work provides fundamental understanding on the correlations among processing methodology, solution pre-aggregation, morphology formation kinetics, device physics and device performance and affords guidance for device optimization in scalable manufacturing.

21 January 2020 in ACS Applied Polymer Materials
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Journal Article
Open access
MJMarcus E. Jawerth
Marcus E. Jawerth
CBCalvin J. Brett
Calvin J. Brett
CTCédric Terrier
Cédric Terrier
PLPer Tomas Larsson
Per Tomas Larsson
MLMartin Lawoko
Martin Lawoko
MJMats Johansson
Mats Johansson
The need for renewable alternatives for fossil based aromatic material constituents is evident for a more sustainable society. Lignin is the largest source of naturally occurring aromatic compounds but has mainly been considered as waste material or energy source in the pulp and paper industry. Developments in extracting lignin from these processes provide a large source for renewable aromatic structures to be used in various different applications. Producing thermosets out of lignin is a very promising route to utilize this raw material towards e.g. composite application. The build-up of the molecular network based on oligomeric lignin segments will be different from traditional thermoset analogues, where the constituents often are smaller molecules, and will have an effect on the material properties. In this work LignoBoost Kraft lignin is refined, chemically modified and used to produce freestanding thermosets with different architecture and properties. These different thermosets are evaluated and the possibilities to tailor the material properties through work up and modification are demonstrated. Morphological studies on the formed thermosets using X-ray scattering show systematic differences in molecular stacking and aggregate sizes.

14 January 2021 in ACS Sustainable Chemistry & Engineering
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Journal Article
Closed access
IRIuliana Ribca
Iuliana Ribca
MJMarcus E. Jawerth
Marcus E. Jawerth
CBCalvin J. Brett
Calvin J. Brett
MLMartin Lawoko
Martin Lawoko
MSMatthias Schwartzkopf
Matthias Schwartzkopf
MJMats Johansson
Mats Johansson