dominique loisnard - Academia.edu (original) (raw)

Papers by dominique loisnard

Research paper thumbnail of Humidity‐Induced Degradation Processes of Halide Perovskites Unveiled by Correlative Analytical Electron Microscopy

Small Methods

Improving the stability of lead halide perovskite solar cells (PSCs) for industrialization is cur... more Improving the stability of lead halide perovskite solar cells (PSCs) for industrialization is currently a major challenge. It is shown that moisture induces changes in global PSC performance, altering the nature of the absorber through phase transition or segregation. Understanding how the material evolves in a wet environment is crucial for optimizing device performance and stability. Here, the chemical and structural evolution of state‐of‐the‐art hybrid perovskite thin‐film Cs0.05(MA0.15FA0.85)0.95Pb(I0.84 Br0.16)3 (CsMAFA) is investigated after aging under controlled humidity with analytical characterization techniques. The analysis is performed at different scales through Photoluminescence, X‐ray Diffraction Spectroscopy, Cathodoluminescence, Selected Area Electron Diffraction, and Energy Dispersive X‐ray Spectroscopy. From the analysis of the degradation products from the perovskite layer and by the correlation of their optical and chemical properties at a microscopic level, di...

Research paper thumbnail of Validity of Crystal Plasticity Models Near Grain Boundaries: Contribution of Elastic Strain Measurements at Micron Scale

JOM, Aug 6, 2019

HAL is a multidisciplinary open access archive for the deposit and dissemination of scientific re... more HAL is a multidisciplinary open access archive for the deposit and dissemination of scientific research documents, whether they are published or not. The documents may come from teaching and research institutions in France or abroad, or from public or private research centers. L'archive ouverte pluridisciplinaire HAL, est destinée au dépôt et à la diffusion de documents scientifiques de niveau recherche, publiés ou non, émanant des établissements d'enseignement et de recherche français ou étrangers, des laboratoires publics ou privés.

Research paper thumbnail of Microstructural study and in situ investigation of strain localization in ions irradiated austenitic stainless steels

HAL (Le Centre pour la Communication Scientifique Directe), 2006

... International Symposium Fontevraud IV, SFEN,183. [18] Krummeich R, Pareige P, Massoud JP, Jum... more ... International Symposium Fontevraud IV, SFEN,183. [18] Krummeich R, Pareige P, Massoud JP, Jumel S, Surf Interface Anal, 36 (2004), 575-580. ... [22] Lee EH, Yoo MH, Byun TS, Hunn JD, Farrell K, Mansur LK, Acta mater 49;2001:3277. ...

Research paper thumbnail of Link between Bcc-Fcc Orientation Relationship and Austenite Morphology in Cf8m Stainless Steel

Research paper thumbnail of Indexation of electron diffraction patterns at grain boundaries

Materials Characterization, Dec 1, 2021

Grain boundaries play a vital role in materials science, and they are extensively studied through... more Grain boundaries play a vital role in materials science, and they are extensively studied through experimental and numerical methods. Electron backscatter diffraction (EBSD) is commonly used to characterize crystalline materials, yet its performance is often compromised at grain boundaries. The key difficulty is to index the overlapped electron backscatter patterns, where Kikuchi bands from multiple crystal orientations coexist. Houghindexation often fails in treating overlapped EBSP, while the recently proposed dictionary indexation and sphere indexation give only one triplet of Euler angles from overlapped patterns. For all these methods, the orientation indexing precision drops for overlapped EBSP. Here we propose an integrated Digital Image Correlation (DIC) procedure to determine simultaneously and precisely multiple crystal orientations by registering the overlapped EBSP and the master pattern. The contribution ratio of each crystal orientation to the overlapped pattern is also available. Through an experimental EBSD dataset around a triple point, multiple benefits of the rich results from the method are demonstrated, such as refining grain boundaries, revealing EBSD scan errors and quantifying spatial resolution of EBSD. At the grain boundaries, the crystal orientation measurement uncertainty is 0.03°for both indexed crystal orientations, the same order for grain interiors, while their contribution ratios of uncertainty around 0.02 are obtained.

Research paper thumbnail of Measuring topographies from conventional SEM acquisitions

Ultramicroscopy, Aug 1, 2018

The present study extends the stereoscopic imaging principle for estimating the surface topograph... more The present study extends the stereoscopic imaging principle for estimating the surface topography to two orientations, namely, normal to the electron beam axis and inclined at 70°as suited for EBSD analyses. In spite of the large angle difference, it is shown that the topography can be accurately determined using regularized global Digital Image Correlation. The surface topography is compared to another estimate issued from a 3D FIB-SEM procedure where the sample surface is first covered by a Pt layer, and its initial topography is progressively revealed from successive FIB-milling. These two methods are successfully compared on a 6% strained steel specimen in an in situ mechanical test. This analysis is supplemented by a third approach estimating the change of topography from crystal rotations as measured from successive EBSD images. This last technique ignores plastic deformation, and thus only holds in an elastic regime. For the studied example, despite the large plastic flow, it is shown that crystal rotation already accounts for a significant part of the deformation-induced topography.

Research paper thumbnail of Correlative analysis of perovskite solar cells aged under humidity

Research paper thumbnail of Enhanced EBSD calibration accuracy based on gradients of diffraction patterns

Materials Characterization, May 1, 2023

Research paper thumbnail of Analysis of the degradation products of hybrid perovskite by correlative electron microscopy

Proceedings of the International Conference on Hybrid and Organic Photovoltaics, Apr 20, 2022

Research paper thumbnail of Irradiation Hardening of Austenitic Stainless Steels: From Field Experience to Modeling

ABSTRACT Materials for the core internals of Pressurized Water Reactors (austenitic stainless ste... more ABSTRACT Materials for the core internals of Pressurized Water Reactors (austenitic stainless steels) are submitted to neutron irradiation. To understand the ageing mechanisms associated to irradiation and propose life predictions of the component, a multi step iterative approach consisting in particular in modeling the evolution of the hardening has been undertaken. Combination of characterization and modeling of simplified situations and field expertise is proposed.

Research paper thumbnail of Direct measurement of local constitutive relations, at the micrometre scale, in bulk metallic alloys

Journal of Applied Crystallography, Jun 1, 2017

Multiscale models involving crystal plasticity are essential to predict the elastoplastic behavio... more Multiscale models involving crystal plasticity are essential to predict the elastoplastic behavior of structural materials with respect to their microstructure. However, those models are often limited by a poor knowledge of the local constitutive behavior. This article reports a method to measure the mechanical behavior directly, at the micrometre scale, in bulk crystalline materials. Local strain and stress states were evaluated at the surface of a bent stainless steel crystal by combining total strain measurements-performed with the digital image correlation technique on optical images-with elastic strain measurements obtained by Laue microdiffraction. A local constitutive relation was measured, in an efficient nondestructive way, without the need for full-field simulations. The method was validated by a comparison between the measured local behavior and the macroscopic behavior of the single crystal.

Research paper thumbnail of One‐Step Slot‐Die Coating Deposition of Wide‐Bandgap Perovskite Absorber for Highly Efficient Solar Cells

Solar RRL, Jul 22, 2021

Slot-die coating is a promising technique paving the way for large-area perovskite deposition and... more Slot-die coating is a promising technique paving the way for large-area perovskite deposition and commercially relevant solar devices fabrication with sharp control over the thickness and material composition. However, before transferring perovskite solar cells technology to commercial applications, it is required to develop ink formulations guaranteeing 2 high homogeneity over wide surface and leading to large, defects-free and well-crystallized perovskite grains to maximize the device performances. We report a one-step slot-die deposition route, combining ink tailoring and vacuum aspiration solvent extraction affording the deposition of high bandgap multi-cation perovskite. One important key is the introduction of methylammonium chloride in the ink formulation which substantially enhances the film quality over large area. Although the efficacy of anti-solvent dripping is demonstrated on small area, it is not compatible with larger area. This work compares the latter with a vacuum quench protocol allowing efficient extraction of the solvents. Considering both ink formulation engineering and vacuum solvent extraction, we reached a stabilized power conversion efficiency of up to 17.5 %. This constitutes, to the best of our knowledge, the highest reported value for a high bandgap absorber deposited by slot-die coating. Moreover, stability over 180 hours under maximum power point conditions is herein demonstrated.

Research paper thumbnail of Calibration of crystal orientation and pattern center of EBSD using integrated digital image correlation

Materials Characterization, Aug 1, 2021

The accuracy of electron backscatter diffraction indexation has long been limited by pattern cent... more The accuracy of electron backscatter diffraction indexation has long been limited by pattern center determination, and numerous hardware and software methods have been proposed to improve the calibration. Here, an Integrated Digital Image Correlation (IDIC) procedure is proposed to determine simultaneously crystal orientation and pattern center by registering experimental and simulated electron diffraction patterns. To assess the performance and robustness of the procedure, numerous case studies are reported. Noise sensitivity is first explored on virtual data to assess convergence conditions and result uncertainty up to high noise level and small detector size. Two experimental data sets are further exploited. First, a high-definition detector shows that crystal orientation uncertainty as low as 3×10 −2 degrees can be achieved, that is at least 80% less than commercial Hough-transformation based indexation method. Different sample tilt angles are tested, IDIC indexation proves much more tolerant with imprecise tilt angles than common EBSD indexation methods. Second, fast EBSD acquisitions with a coarse definition performed during an in-situ tensile test are analyzed. A quantification of the residual noise allows one to formulate an optimized IDIC functional with a proper pixel-wise weight. With the latter refinement a two-pass procedure leads to a much enhanced precision of the determination of crystal orientation, giving access to more precise evaluation of maps of geometrically necessary dislocation densities.

Research paper thumbnail of On the Accuracy of Elastic Strain Field Measurements by Laue Microdiffraction and High-Resolution EBSD: a Cross-Validation Experiment

Experimental Mechanics, Dec 11, 2015

HAL is a multidisciplinary open access archive for the deposit and dissemination of scientific re... more HAL is a multidisciplinary open access archive for the deposit and dissemination of scientific research documents, whether they are published or not. The documents may come from teaching and research institutions in France or abroad, or from public or private research centers. L'archive ouverte pluridisciplinaire HAL, est destinée au dépôt et à la diffusion de documents scientifiques de niveau recherche, publiés ou non, émanant des établissements d'enseignement et de recherche français ou étrangers, des laboratoires publics ou privés.

Research paper thumbnail of Link between Bcc-Fcc Orientation Relationship and Austenite Morphology in Cf8m Stainless Steel

Research paper thumbnail of Enhanced Ebsd Calibration Accuracy Based on Gradients of Diffraction Patterns

Social Science Research Network, 2023

Research paper thumbnail of Microstructural Study and in Situ Investigation of Strain Localization in Ions Irradiated Austenitic Stainless Steels

iweb.tms.org

... International Symposium Fontevraud IV, SFEN,183. [18] Krummeich R, Pareige P, Massoud JP, Jum... more ... International Symposium Fontevraud IV, SFEN,183. [18] Krummeich R, Pareige P, Massoud JP, Jumel S, Surf Interface Anal, 36 (2004), 575-580. ... [22] Lee EH, Yoo MH, Byun TS, Hunn JD, Farrell K, Mansur LK, Acta mater 49;2001:3277. ...

Research paper thumbnail of Enhanced EBSD calibration accuracy based on gradients of diffraction patterns

Materials Characterization

Research paper thumbnail of Analysis of the degradation products of hybrid perovskite by correlative electron microscopy

Proceedings of the International Conference on Hybrid and Organic Photovoltaics, Apr 20, 2022

Research paper thumbnail of Correlative analysis of perovskite solar cells aged under humidity

Physics, Simulation, and Photonic Engineering of Photovoltaic Devices XI, 2022

Research paper thumbnail of Humidity‐Induced Degradation Processes of Halide Perovskites Unveiled by Correlative Analytical Electron Microscopy

Small Methods

Improving the stability of lead halide perovskite solar cells (PSCs) for industrialization is cur... more Improving the stability of lead halide perovskite solar cells (PSCs) for industrialization is currently a major challenge. It is shown that moisture induces changes in global PSC performance, altering the nature of the absorber through phase transition or segregation. Understanding how the material evolves in a wet environment is crucial for optimizing device performance and stability. Here, the chemical and structural evolution of state‐of‐the‐art hybrid perovskite thin‐film Cs0.05(MA0.15FA0.85)0.95Pb(I0.84 Br0.16)3 (CsMAFA) is investigated after aging under controlled humidity with analytical characterization techniques. The analysis is performed at different scales through Photoluminescence, X‐ray Diffraction Spectroscopy, Cathodoluminescence, Selected Area Electron Diffraction, and Energy Dispersive X‐ray Spectroscopy. From the analysis of the degradation products from the perovskite layer and by the correlation of their optical and chemical properties at a microscopic level, di...

Research paper thumbnail of Validity of Crystal Plasticity Models Near Grain Boundaries: Contribution of Elastic Strain Measurements at Micron Scale

JOM, Aug 6, 2019

HAL is a multidisciplinary open access archive for the deposit and dissemination of scientific re... more HAL is a multidisciplinary open access archive for the deposit and dissemination of scientific research documents, whether they are published or not. The documents may come from teaching and research institutions in France or abroad, or from public or private research centers. L'archive ouverte pluridisciplinaire HAL, est destinée au dépôt et à la diffusion de documents scientifiques de niveau recherche, publiés ou non, émanant des établissements d'enseignement et de recherche français ou étrangers, des laboratoires publics ou privés.

Research paper thumbnail of Microstructural study and in situ investigation of strain localization in ions irradiated austenitic stainless steels

HAL (Le Centre pour la Communication Scientifique Directe), 2006

... International Symposium Fontevraud IV, SFEN,183. [18] Krummeich R, Pareige P, Massoud JP, Jum... more ... International Symposium Fontevraud IV, SFEN,183. [18] Krummeich R, Pareige P, Massoud JP, Jumel S, Surf Interface Anal, 36 (2004), 575-580. ... [22] Lee EH, Yoo MH, Byun TS, Hunn JD, Farrell K, Mansur LK, Acta mater 49;2001:3277. ...

Research paper thumbnail of Link between Bcc-Fcc Orientation Relationship and Austenite Morphology in Cf8m Stainless Steel

Research paper thumbnail of Indexation of electron diffraction patterns at grain boundaries

Materials Characterization, Dec 1, 2021

Grain boundaries play a vital role in materials science, and they are extensively studied through... more Grain boundaries play a vital role in materials science, and they are extensively studied through experimental and numerical methods. Electron backscatter diffraction (EBSD) is commonly used to characterize crystalline materials, yet its performance is often compromised at grain boundaries. The key difficulty is to index the overlapped electron backscatter patterns, where Kikuchi bands from multiple crystal orientations coexist. Houghindexation often fails in treating overlapped EBSP, while the recently proposed dictionary indexation and sphere indexation give only one triplet of Euler angles from overlapped patterns. For all these methods, the orientation indexing precision drops for overlapped EBSP. Here we propose an integrated Digital Image Correlation (DIC) procedure to determine simultaneously and precisely multiple crystal orientations by registering the overlapped EBSP and the master pattern. The contribution ratio of each crystal orientation to the overlapped pattern is also available. Through an experimental EBSD dataset around a triple point, multiple benefits of the rich results from the method are demonstrated, such as refining grain boundaries, revealing EBSD scan errors and quantifying spatial resolution of EBSD. At the grain boundaries, the crystal orientation measurement uncertainty is 0.03°for both indexed crystal orientations, the same order for grain interiors, while their contribution ratios of uncertainty around 0.02 are obtained.

Research paper thumbnail of Measuring topographies from conventional SEM acquisitions

Ultramicroscopy, Aug 1, 2018

The present study extends the stereoscopic imaging principle for estimating the surface topograph... more The present study extends the stereoscopic imaging principle for estimating the surface topography to two orientations, namely, normal to the electron beam axis and inclined at 70°as suited for EBSD analyses. In spite of the large angle difference, it is shown that the topography can be accurately determined using regularized global Digital Image Correlation. The surface topography is compared to another estimate issued from a 3D FIB-SEM procedure where the sample surface is first covered by a Pt layer, and its initial topography is progressively revealed from successive FIB-milling. These two methods are successfully compared on a 6% strained steel specimen in an in situ mechanical test. This analysis is supplemented by a third approach estimating the change of topography from crystal rotations as measured from successive EBSD images. This last technique ignores plastic deformation, and thus only holds in an elastic regime. For the studied example, despite the large plastic flow, it is shown that crystal rotation already accounts for a significant part of the deformation-induced topography.

Research paper thumbnail of Correlative analysis of perovskite solar cells aged under humidity

Research paper thumbnail of Enhanced EBSD calibration accuracy based on gradients of diffraction patterns

Materials Characterization, May 1, 2023

Research paper thumbnail of Analysis of the degradation products of hybrid perovskite by correlative electron microscopy

Proceedings of the International Conference on Hybrid and Organic Photovoltaics, Apr 20, 2022

Research paper thumbnail of Irradiation Hardening of Austenitic Stainless Steels: From Field Experience to Modeling

ABSTRACT Materials for the core internals of Pressurized Water Reactors (austenitic stainless ste... more ABSTRACT Materials for the core internals of Pressurized Water Reactors (austenitic stainless steels) are submitted to neutron irradiation. To understand the ageing mechanisms associated to irradiation and propose life predictions of the component, a multi step iterative approach consisting in particular in modeling the evolution of the hardening has been undertaken. Combination of characterization and modeling of simplified situations and field expertise is proposed.

Research paper thumbnail of Direct measurement of local constitutive relations, at the micrometre scale, in bulk metallic alloys

Journal of Applied Crystallography, Jun 1, 2017

Multiscale models involving crystal plasticity are essential to predict the elastoplastic behavio... more Multiscale models involving crystal plasticity are essential to predict the elastoplastic behavior of structural materials with respect to their microstructure. However, those models are often limited by a poor knowledge of the local constitutive behavior. This article reports a method to measure the mechanical behavior directly, at the micrometre scale, in bulk crystalline materials. Local strain and stress states were evaluated at the surface of a bent stainless steel crystal by combining total strain measurements-performed with the digital image correlation technique on optical images-with elastic strain measurements obtained by Laue microdiffraction. A local constitutive relation was measured, in an efficient nondestructive way, without the need for full-field simulations. The method was validated by a comparison between the measured local behavior and the macroscopic behavior of the single crystal.

Research paper thumbnail of One‐Step Slot‐Die Coating Deposition of Wide‐Bandgap Perovskite Absorber for Highly Efficient Solar Cells

Solar RRL, Jul 22, 2021

Slot-die coating is a promising technique paving the way for large-area perovskite deposition and... more Slot-die coating is a promising technique paving the way for large-area perovskite deposition and commercially relevant solar devices fabrication with sharp control over the thickness and material composition. However, before transferring perovskite solar cells technology to commercial applications, it is required to develop ink formulations guaranteeing 2 high homogeneity over wide surface and leading to large, defects-free and well-crystallized perovskite grains to maximize the device performances. We report a one-step slot-die deposition route, combining ink tailoring and vacuum aspiration solvent extraction affording the deposition of high bandgap multi-cation perovskite. One important key is the introduction of methylammonium chloride in the ink formulation which substantially enhances the film quality over large area. Although the efficacy of anti-solvent dripping is demonstrated on small area, it is not compatible with larger area. This work compares the latter with a vacuum quench protocol allowing efficient extraction of the solvents. Considering both ink formulation engineering and vacuum solvent extraction, we reached a stabilized power conversion efficiency of up to 17.5 %. This constitutes, to the best of our knowledge, the highest reported value for a high bandgap absorber deposited by slot-die coating. Moreover, stability over 180 hours under maximum power point conditions is herein demonstrated.

Research paper thumbnail of Calibration of crystal orientation and pattern center of EBSD using integrated digital image correlation

Materials Characterization, Aug 1, 2021

The accuracy of electron backscatter diffraction indexation has long been limited by pattern cent... more The accuracy of electron backscatter diffraction indexation has long been limited by pattern center determination, and numerous hardware and software methods have been proposed to improve the calibration. Here, an Integrated Digital Image Correlation (IDIC) procedure is proposed to determine simultaneously crystal orientation and pattern center by registering experimental and simulated electron diffraction patterns. To assess the performance and robustness of the procedure, numerous case studies are reported. Noise sensitivity is first explored on virtual data to assess convergence conditions and result uncertainty up to high noise level and small detector size. Two experimental data sets are further exploited. First, a high-definition detector shows that crystal orientation uncertainty as low as 3×10 −2 degrees can be achieved, that is at least 80% less than commercial Hough-transformation based indexation method. Different sample tilt angles are tested, IDIC indexation proves much more tolerant with imprecise tilt angles than common EBSD indexation methods. Second, fast EBSD acquisitions with a coarse definition performed during an in-situ tensile test are analyzed. A quantification of the residual noise allows one to formulate an optimized IDIC functional with a proper pixel-wise weight. With the latter refinement a two-pass procedure leads to a much enhanced precision of the determination of crystal orientation, giving access to more precise evaluation of maps of geometrically necessary dislocation densities.

Research paper thumbnail of On the Accuracy of Elastic Strain Field Measurements by Laue Microdiffraction and High-Resolution EBSD: a Cross-Validation Experiment

Experimental Mechanics, Dec 11, 2015

HAL is a multidisciplinary open access archive for the deposit and dissemination of scientific re... more HAL is a multidisciplinary open access archive for the deposit and dissemination of scientific research documents, whether they are published or not. The documents may come from teaching and research institutions in France or abroad, or from public or private research centers. L'archive ouverte pluridisciplinaire HAL, est destinée au dépôt et à la diffusion de documents scientifiques de niveau recherche, publiés ou non, émanant des établissements d'enseignement et de recherche français ou étrangers, des laboratoires publics ou privés.

Research paper thumbnail of Link between Bcc-Fcc Orientation Relationship and Austenite Morphology in Cf8m Stainless Steel

Research paper thumbnail of Enhanced Ebsd Calibration Accuracy Based on Gradients of Diffraction Patterns

Social Science Research Network, 2023

Research paper thumbnail of Microstructural Study and in Situ Investigation of Strain Localization in Ions Irradiated Austenitic Stainless Steels

iweb.tms.org

... International Symposium Fontevraud IV, SFEN,183. [18] Krummeich R, Pareige P, Massoud JP, Jum... more ... International Symposium Fontevraud IV, SFEN,183. [18] Krummeich R, Pareige P, Massoud JP, Jumel S, Surf Interface Anal, 36 (2004), 575-580. ... [22] Lee EH, Yoo MH, Byun TS, Hunn JD, Farrell K, Mansur LK, Acta mater 49;2001:3277. ...

Research paper thumbnail of Enhanced EBSD calibration accuracy based on gradients of diffraction patterns

Materials Characterization

Research paper thumbnail of Analysis of the degradation products of hybrid perovskite by correlative electron microscopy

Proceedings of the International Conference on Hybrid and Organic Photovoltaics, Apr 20, 2022

Research paper thumbnail of Correlative analysis of perovskite solar cells aged under humidity

Physics, Simulation, and Photonic Engineering of Photovoltaic Devices XI, 2022