Florian Werner
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View article: Validating soil moisture models for wildfire risk assessment 
Validating soil moisture models for wildfire risk assessment  Open
Soil moisture is an important variable in wildfire risk assessment, influencing fuel moisture content, fire ignition potential and fire spread dynamics. In the existing fire danger rating systems, soil moisture is largely overlooked while …
View article: Induced Subforests and Superforests
Induced Subforests and Superforests Open
Graph isomorphism, subgraph isomorphism, and maximum common subgraphs are classical well-investigated objects. Their (parameterized) complexity and efficiently tractable cases have been studied. In the present paper, for a given set of for…
View article: Largest common subgraph of two forests
Largest common subgraph of two forests Open
A common subgraph of two graphs $G_1$ and $G_2$ is a graph that is isomorphic to subgraphs of $G_1$ and $G_2$. In the largest common subgraph problem the task is to determine a common subgraph for two given graphs $G_1$ and $G_2$ that is o…
View article: 3D stimulated Raman spectral imaging of water dynamics associated with pectin-glycocalyceal entanglement
3D stimulated Raman spectral imaging of water dynamics associated with pectin-glycocalyceal entanglement Open
Pectin is a heteropolysaccharide responsible for the structural integrity of the cell walls of terrestrial plants. When applied to the surface of mammalian visceral organs, pectin films form a strong physical bond with the surface glycocal…
View article: Thermal infrared earth observation for operational irrigation management
Thermal infrared earth observation for operational irrigation management Open
Irrigation water use in agriculture is a major drain on the world’s freshwater reserves. Optimizing irrigation water use and accurately assessing crop responses to water stress in near-real-time is becoming increasingly important due…
View article: Toward high resolution and daily thermal infrared measurements for agricultural water management
Toward high resolution and daily thermal infrared measurements for agricultural water management Open
Sustainable water use in agriculture, while ensuring high yield returns, is key to tackling challenges imposed by climate change and population growth. Knowing the crop water status within the field allows for optimized water consumption b…
View article: Revisiting crop water stress index based on potato field experiments in Northern Germany
Revisiting crop water stress index based on potato field experiments in Northern Germany Open
Different types of the Crop Water Stress Index (CWSI) have been useful for water stress monitoring and irrigation management in semi-arid regions, however little research exists on its effective application in humid regions. This study aim…
View article: Determination of the gasket characteristics at cryogenic temperatures
Determination of the gasket characteristics at cryogenic temperatures Open
So far, the knowledge about gasket characteristics in cryogenic conditions is still limited.The determination of gasket factors according to EN13555 would give the possibility to calculate flange connections according to EN1591-1.In this p…
View article: Near surface defects: Cause of deficit between internal and external open‐circuit voltage in solar cells
Near surface defects: Cause of deficit between internal and external open‐circuit voltage in solar cells Open
Interface recombination in a complex multilayered thin‐film solar structure causes a disparity between the internal open‐circuit voltage ( V OC,in ), measured by photoluminescence, and the external open‐circuit voltage ( V OC,ex ), that is…
View article: Near surface defects: Cause of deficit between internal and external open-circuit voltage in solar cells
Near surface defects: Cause of deficit between internal and external open-circuit voltage in solar cells Open
The presence of interface recombination in a complex multilayered thin-film solar structure causes a disparity between the internal open-circuit voltage (VOC,in), measured by photoluminescence, and the external open-circuit voltage (VOC,ex…
View article: Near surface defects: Cause of deficit between internal and external open-circuit voltage in solar cells
Near surface defects: Cause of deficit between internal and external open-circuit voltage in solar cells Open
Here def files of models used in SCAPS-1D for simulations and the raw measured data of Fig. 1 a and c, 2a, 3b and d presented in the manuscript "Near surface defects: Cause of deficit between internal and external open-circuit voltage in s…
View article: Passivating Surface Defects and Reducing Interface Recombination in CuInS<sub>2</sub> Solar Cells by a Facile Solution Treatment
Passivating Surface Defects and Reducing Interface Recombination in CuInS<sub>2</sub> Solar Cells by a Facile Solution Treatment Open
Interface recombination at the absorber surface impedes the efficiency of a solar cell with an otherwise excellent absorber. The internal voltage or quasi‐Fermi‐level splitting (qFLs) measures the quality of the absorber. Interface recombi…
View article: Passivating Surface Defects and Reducing Interface Recombination in CuInS2 Solar Cells by a Facile Solution Treatment
Passivating Surface Defects and Reducing Interface Recombination in CuInS2 Solar Cells by a Facile Solution Treatment Open
Interface recombination at the absorber buffer interface impedes the efficiency of a solar cell with an otherwise excellent absorber. The internal voltage or the quasi-Fermi level splitting (qFLs) measures the quality of the absorber. Inte…
View article: Passivating Surface Defects and Reducing Interface Recombination in\n CuInS2 Solar Cells by a Facile Solution Treatment
Passivating Surface Defects and Reducing Interface Recombination in\n CuInS2 Solar Cells by a Facile Solution Treatment Open
Interface recombination at the absorber buffer interface impedes the\nefficiency of a solar cell with an otherwise excellent absorber. The internal\nvoltage or the quasi-Fermi level splitting (qFLs) measures the quality of the\nabsorber. I…
View article: Absorber composition: A critical parameter for the effectiveness of heat treatments in chalcopyrite solar cells
Absorber composition: A critical parameter for the effectiveness of heat treatments in chalcopyrite solar cells Open
Post‐device heat treatment (HT) in chalcopyrite [Cu (In,Ga)(S,Se) 2 ] solar cells is known to improve the performance of the devices. However, this HT is only beneficial for devices made with absorbers grown under Cu‐poor conditions but no…
View article: Ultra-thin passivation layers in Cu(In,Ga)Se2 thin-film solar cells: full-area passivated front contacts and their impact on bulk doping
Ultra-thin passivation layers in Cu(In,Ga)Se2 thin-film solar cells: full-area passivated front contacts and their impact on bulk doping Open
In the search for highly transparent and non-toxic alternative front layers replacing state-of-the-art CdS in Cu(In,Ga)Se 2 thin-film solar cells, alternatives rarely exceed reference devices in terms of efficiency. Full-area ultra-thin al…
View article: Heavy Alkali Treatment of Cu(In,Ga)Se<sub>2</sub> Solar Cells: Surface versus Bulk Effects
Heavy Alkali Treatment of Cu(In,Ga)Se<sub>2</sub> Solar Cells: Surface versus Bulk Effects Open
Chalcopyrite solar cells achieve efficiencies above 23%. The latest improvements are due to post‐deposition treatments (PDT) with heavy alkalis. This study provides a comprehensive description of the effect of PDT on the chemical and elect…
View article: Atmospheric-Pressure Synthesis of Atomically Smooth, Conformal, and Ultrathin Low-<i>k</i> Polymer Insulating Layers by Plasma-Initiated Chemical Vapor Deposition
Atmospheric-Pressure Synthesis of Atomically Smooth, Conformal, and Ultrathin Low-<i>k</i> Polymer Insulating Layers by Plasma-Initiated Chemical Vapor Deposition Open
The straightforward synthesis of ultrathin low dielectric constant insulating polymer layers from four cyclic organosilicon monomers (i.e., two organocyclosiloxanes and two organocyclosilazanes) by atmospheric pressure plasma-initiated che…
View article: Can we see defects in capacitance measurements of thin‐film solar cells?
Can we see defects in capacitance measurements of thin‐film solar cells? Open
Thermal admittance spectroscopy and capacitance‐voltage measurements are well established techniques to study recombination‐active deep defect levels and determine the shallow dopant concentration in photovoltaic absorbers. Applied to thin…
View article: Interdiffusion and Doping Gradients at the Buffer/Absorber Interface in Thin-Film Solar Cells
Interdiffusion and Doping Gradients at the Buffer/Absorber Interface in Thin-Film Solar Cells Open
An accurate determination of the net dopant concentration in photovoltaic absorbers is critical for understanding and optimizing solar cell performance. The complex device structure of multilayered thin-film solar cells poses challenges to…
View article: Alkali treatments of Cu(In,Ga)Se<sub>2</sub>thin‐film absorbers and their impact on transport barriers
Alkali treatments of Cu(In,Ga)Se<sub>2</sub>thin‐film absorbers and their impact on transport barriers Open
We study the impact of different alkali post‐deposition treatments by thermal admittance spectroscopy and temperature‐dependent current‐voltage ( IVT ) characteristics of high‐efficiency Cu(In,Ga)Se 2 thin‐film solar cells fabricated from …
View article: Buffer Layers, Defects, and the Capacitance Step in the Admittance Spectrum of a Thin-Film Solar Cell
Buffer Layers, Defects, and the Capacitance Step in the Admittance Spectrum of a Thin-Film Solar Cell Open
Capacitance-based measurements are key to the study of defects in semiconductor devices, and are used extensively in the field of thin-film photovoltaics. In a multilayered thin-film device, however, the mere presence of the layers can res…
View article: High‐performance low bandgap thin film solar cells for tandem applications
High‐performance low bandgap thin film solar cells for tandem applications Open
Thin film tandem solar cells provide a promising approach to achieve high efficiencies. These tandem cells require at least a bottom low bandgap and an upper high bandgap solar cell. In this contribution, 2 high‐performance Cu(In,Ga)Se 2 c…
View article: Space-charge-limited currents in CIS-based solar cells
Space-charge-limited currents in CIS-based solar cells Open
Non-linear shunts in Cu(In,Ga)Se2 solar cells have been well described mathematically using the model of a space-charge-limited current, but their physical origin remained unclear so far. We study space-charge-limited currents on Cu-rich C…
View article: Hall measurements on low-mobility thin films
Hall measurements on low-mobility thin films Open
We review the conventional measuring standard for dc Hall measurements in van der Pauw configuration with particular focus on the challenges arising from a small Hall signal compared to sizable offset voltages, which is a typical scenario …
View article: Photoluminescence studies in epitaxial CZTSe thin films
Photoluminescence studies in epitaxial CZTSe thin films Open
Epitaxial Cu2ZnSnSe4 (CZTSe) thin films were grown by molecular beam epitaxy on GaAs(001) using two different growth processes, one containing an in-situ annealing stage as used for solar cell absorbers and one for which this step was omit…