Chemical Robotics Enabled Exploration of Stability and Photoluminescent Behavior in Multicomponent Hybrid Perovskites via Machine Learning

2020 ◽  
Author(s):  
Kate Higgins ◽  
Sai Mani Valleti ◽  
Maxim Ziatdinov ◽  
Sergei Kalinin ◽  
Mahshid Ahmadi
Keyword(s):  
Machine Learning ◽  
Optimization Methods ◽  
Combinatorial Synthesis ◽  
Ambient Conditions ◽  
Term Stability ◽  
Long Term Stability ◽  
Composition Space ◽  
Materials Research ◽  
The Stability

<p>Hybrid organic-inorganic perovskites have attracted immense interest as a promising material for the next-generation solar cells; however, issues regarding long-term stability still require further study. Here, we develop automated experimental workflow based on combinatorial synthesis and rapid throughput characterization to explore long-term stability of these materials in ambient conditions, and apply it to four model perovskite systems: MA<sub>x</sub>FA<sub>y</sub>Cs<sub>1-x-y</sub>PbBr<sub>3</sub>, MA<sub>x</sub>FA<sub>y</sub>Cs<sub>1-x-y</sub>PbI<sub>3</sub>, (Cs<sub>x</sub>FA<sub>y</sub>MA<sub>1-x-y</sub>Pb(Br<sub>x+y</sub>I<sub>1-x-y</sub>)<sub>3</sub>) and (Cs<sub>x</sub>MA<sub>y</sub>FA<sub>1-x-y</sub>Pb(I<sub>x+y</sub>Br<sub>1-x-y</sub>)<sub>3</sub>). We also develop a machine learning-based workflow to quantify the evolution of each system as a function of composition based on overall changes in photoluminescence spectra, as well as specific peak positions and intensities. We find the stability dependence on composition to be extremely non-uniform within the composition space, suggesting the presence of potential preferential compositional regions. This proposed workflow is universal and can be applied to other perovskite systems and solution-processable materials. Furthermore, incorporation of experimental optimization methods, e.g., those based on Gaussian Processes, will enable the transition from combinatorial synthesis to guide materials research and optimization.</p>

scholarly journals Chemical Robotics Enabled Exploration of Stability and Photoluminescent Behavior in Multicomponent Hybrid Perovskites via Machine Learning

2020 ◽  
Author(s):  
Kate Higgins ◽  
Sai Mani Valleti ◽  
Maxim Ziatdinov ◽  
Sergei Kalinin ◽  
Mahshid Ahmadi
Keyword(s):  
Phase Diagram ◽  
Gaussian Process Regression ◽  
Optimization Methods ◽  
Combinatorial Synthesis ◽  
Ambient Conditions ◽  
Term Stability ◽  
Long Term Stability ◽  
Sensing Applications ◽  
Multiple Materials

<p></p><p>Hybrid organic-inorganic perovskites have attracted immense interest as a promising material for a variety of optoelectronic and sensing applications. However, issues regarding long-term stability have emerged as the key bottleneck for applications and still require further study. Here, we develop automated experimental workflow based on combinatorial synthesis and rapid throughput characterization to explore long-term stability of these materials in ambient conditions, and apply it to four model perovskite systems: <a></a><a>MA<i><sub>x</sub></i>FA<i><sub>y</sub></i>Cs<sub>1-<i>x</i>-<i>y</i></sub>PbBr<sub>3</sub>, MA<i><sub>x</sub></i>FA<i><sub>y</sub></i>Cs<sub>1-<i>x</i>-<i>y</i></sub>PbI<sub>3</sub>, Cs<i><sub>x</sub></i>FA<i><sub>y</sub></i>MA<sub>1-<i>x</i>-<i>y</i></sub>Pb(Br<i><sub>x</sub></i><sub>+<i>y</i></sub>I<sub>1-<i>x</i>-<i>y</i></sub>)<sub>3</sub> and Cs<i><sub>x</sub></i>MA<i><sub>y</sub></i>FA<sub>1-<i>x</i>-<i>y</i></sub>Pb(I<i><sub>x</sub></i><sub>+<i>y</i></sub>Br<sub>1-<i>x</i>-<i>y</i></sub>)<sub>3</sub></a>. We have both established a new workflow and found out the main tendencies in the mixed cation and anion systems, which led to the discovery of non-trivial composition regions with high stability. The Non-negative Matrix Factorization and Gaussian Process regression are used <i>to</i> <i>interpolate the photoluminescent behavior of vast compositional space</i> and <i>to study the overall behavior of the phase diagram</i>. This interpolative regression analysis helps to distinguish mixtures that form solid solutions from those that segregate into multiple materials, pointing out the most stable regions of the phase diagram. We find the stability dependence on composition to be extremely non-uniform within the composition space, suggesting the presence of potential preferential compositional regions. <a>This proposed workflow is universal and can be applied to other perovskite systems and solution-processable materials. </a>Furthermore, incorporation of experimental optimization methods, e.g., those based on Gaussian Processes, will enable the transition from combinatorial synthesis to guide materials research and optimization.</p><p></p>

scholarly journals Chemical Robotics Enabled Exploration of Stability and Photoluminescent Behavior in Multicomponent Hybrid Perovskites via Machine Learning

2020 ◽  
Author(s):  
Kate Higgins ◽  
Sai Mani Valleti ◽  
Maxim Ziatdinov ◽  
Sergei Kalinin ◽  
Mahshid Ahmadi
Keyword(s):  
Phase Diagram ◽  
Gaussian Process Regression ◽  
Optimization Methods ◽  
Combinatorial Synthesis ◽  
Ambient Conditions ◽  
Term Stability ◽  
Long Term Stability ◽  
Sensing Applications ◽  
Multiple Materials

<p></p><p>Hybrid organic-inorganic perovskites have attracted immense interest as a promising material for a variety of optoelectronic and sensing applications. However, issues regarding long-term stability have emerged as the key bottleneck for applications and still require further study. Here, we develop automated experimental workflow based on combinatorial synthesis and rapid throughput characterization to explore long-term stability of these materials in ambient conditions, and apply it to four model perovskite systems: <a></a><a>MA<i><sub>x</sub></i>FA<i><sub>y</sub></i>Cs<sub>1-<i>x</i>-<i>y</i></sub>PbBr<sub>3</sub>, MA<i><sub>x</sub></i>FA<i><sub>y</sub></i>Cs<sub>1-<i>x</i>-<i>y</i></sub>PbI<sub>3</sub>, Cs<i><sub>x</sub></i>FA<i><sub>y</sub></i>MA<sub>1-<i>x</i>-<i>y</i></sub>Pb(Br<i><sub>x</sub></i><sub>+<i>y</i></sub>I<sub>1-<i>x</i>-<i>y</i></sub>)<sub>3</sub> and Cs<i><sub>x</sub></i>MA<i><sub>y</sub></i>FA<sub>1-<i>x</i>-<i>y</i></sub>Pb(I<i><sub>x</sub></i><sub>+<i>y</i></sub>Br<sub>1-<i>x</i>-<i>y</i></sub>)<sub>3</sub></a>. We have both established a new workflow and found out the main tendencies in the mixed cation and anion systems, which led to the discovery of non-trivial composition regions with high stability. The Non-negative Matrix Factorization and Gaussian Process regression are used <i>to</i> <i>interpolate the photoluminescent behavior of vast compositional space</i> and <i>to study the overall behavior of the phase diagram</i>. This interpolative regression analysis helps to distinguish mixtures that form solid solutions from those that segregate into multiple materials, pointing out the most stable regions of the phase diagram. We find the stability dependence on composition to be extremely non-uniform within the composition space, suggesting the presence of potential preferential compositional regions. <a>This proposed workflow is universal and can be applied to other perovskite systems and solution-processable materials. </a>Furthermore, incorporation of experimental optimization methods, e.g., those based on Gaussian Processes, will enable the transition from combinatorial synthesis to guide materials research and optimization.</p><p></p>

scholarly journals Long-term stability in γ-CsPbI3 perovskite via an ultraviolet-curable polymer network

2021 ◽  
Vol 2 (1) ◽  
Author(s):  
Nam-Kwang Cho ◽  
Hyun-Jae Na ◽  
Jeeyoung Yoo ◽  
Youn Sang Kim
Keyword(s):  
Polymer Network ◽  
Lone Pair ◽  
Ambient Conditions ◽  
Absorption Properties ◽  
Term Stability ◽  
Long Term Stability ◽  
Ultraviolet Curable ◽  
Oxygen Lone Pair ◽  
Lone Pair Electrons

AbstractBlack-colored (α, γ-phase) CsPbI3 perovskites have a small bandgap and excellent absorption properties in the visible light regime, making them attractive for solar cells. However, their long-term stability in ambient conditions is limited. Here, we demonstrate a strategy to improve structural and electrical long-term stability in γ-CsPbI3 by the use of an ultraviolet-curable polyethylene glycol dimethacrylate (PEGDMA) polymer network. Oxygen lone pair electrons from the PEGDMA are found to capture Cs+ and Pb2+ cations, improving crystal growth of γ-CsPbI3 around PEGDMA. In addition, the PEGDMA polymer network strongly contributes to maintaining the black phase of γ-CsPbI3 for more than 35 days in air, and an optimized perovskite film retained ~90% of its initial electrical properties under red, green, and blue light irradiation.

LONG-TERM STABILITY ANALYSIS OF ACOUSTIC ABSORBING BOUNDARY CONDITIONS

2013 ◽  
Vol 23 (11) ◽  
pp. 2129-2154 ◽  
Author(s):  
HÉLÈNE BARUCQ ◽  
JULIEN DIAZ ◽  
VÉRONIQUE DUPRAT
Keyword(s):  
Stability Analysis ◽  
Boundary Conditions ◽  
Absorbing Boundary Conditions ◽  
Computational Domain ◽  
Acoustic Wave Equation ◽  
Absorbing Boundary ◽  
Term Stability ◽  
Long Term Stability ◽  
The Stability

This work deals with the stability analysis of a one-parameter family of Absorbing Boundary Conditions (ABC) that have been derived for the acoustic wave equation. We tackle the problem of long-term stability of the wave field both at the continuous and the numerical levels. We first define a function of energy and show that it is decreasing in time. Its discrete form is also decreasing under a Courant–Friedrichs–Lewy (CFL) condition that does not depend on the ABC. Moreover, the decay rate of the continuous energy can be determined: it is exponential if the computational domain is star-shaped and this property can be illustrated numerically.

Fabrication of Boron Compensated Hydrogenated Amorphous Silicon Films with Significantly Improved Stability Using Plasma Enhanced Chemical Vapor Deposition Technique

1995 ◽  
Vol 377 ◽  
Author(s):  
Mohan K. Bhan
Keyword(s):  
Chemical Vapor ◽  
Short Term ◽  
Term Stability ◽  
Long Term Stability ◽  
Vapor Deposition Technique ◽  
Improved Stability ◽  
Donor Acceptor ◽  
B Doping ◽  
The Stability

ABSTRACTWe have systematically investigated the effects of addition of sub-ppm levels of boron on the stability of a-Si:H films and p-i-n devices, deposited by PE-CVD technique. The films thus produced with appropriate amounts of boron, show a significant improvement in stability, when soaked under both AM 1.5 (short-term) as well as 10×sun (long-term) illumination conditions. The opto-electronic properties of the films are quite respectable It is concluded that boron compensates the native impurities by forming donor-acceptor pairs, which reduces the “fast” defects and hence the initial degradation of the films. It is also speculated that boron may also be improving the short-term stability, by reducing the recombination of light generated electrons and holes, by converting D° into D+ states. The long-term stability appears to get affected by hydrogen dilution which seems to reduce the amount of “slow” defects. As a result of B doping of i-layer, the initial conversion efficiency of the devices decreases. It is presumed that our devices may contain an enhanced level of boron impurity, than expected, making them as worse material and to degrade less.

scholarly journals Long-Term Stability Comparison between an Original and a Generic Version of Piperacillin/Tazobactam in Dextrose 5 % Infusion Polyolefin Bags at 5 ± 3 °C after Microwave Freeze-Thaw Treatment

2018 ◽  
Vol 3 (3) ◽  
pp. 143-151
Author(s):  
Sophie Huvelle ◽  
Marie Godet ◽  
Laurence Galanti ◽  
Mélanie Closset ◽  
Benoît Bihin ◽  
...  
Keyword(s):  
Generic Version ◽  
Generic Product ◽  
Brand Name ◽  
Term Stability ◽  
Long Term Stability ◽  
Ph Values ◽  
Lower Confidence ◽  
The Stability ◽  
Aseptic Conditions

AbstractBackgroundPiperacillin-Tazobactam is frequently infused in hospitals. The use of a generic version was considered after the out of stock of the brand name Tazocin®. The stability of 4 g of Tazocin®in 120 mL of dextrose 5 % (D5) was demonstrated during 35 days at 5 °C ± 3 °C after freezing (−20 °C) and microwave thawing (FMT). The aim of the study was to investigate and compare the long-term stability of Tazocin®and a generic product in the same conditions.MethodsFive polyolefin bags of 4 g of Piperacillin/Tazobactam®Sandoz and 5 bags of 4 g of Tazocin®were prepared under aseptic conditions in 120 mL of D5 and stored 3 months at 20 °C then thawed and stored 58 days at 5 ± 3 °C.Spectrophotometric absorbance at different wavelengths, pH measurement, visual and microscopic observations were also performed.The concentrations were measured by HPLC, at 211 nm for tazobactam and 230 nm for piperacilline.ResultsNo significant change in pH values or optic densities, no crystals were detected. The lower confidence limit at 95 % of the concentration for the solutions remains superior to 90 % of the initial concentration until 58 days of storage at 5 ± 3 °C.ConclusionUnder these conditions, 4 g/120 mL of Piperacillin/Tazobactam®Sandoz or Tazocin®in D5 infusion in polyolefin bags remains stable at least for 58 days at 5 ± 3 °C after FMT

Controlled Surface Fermi-level on the SeS2-passivated n-GaAs (100)

1998 ◽  
Vol 510 ◽  
Author(s):  
Jing xi Sun ◽  
F. J. Himpsel ◽  
T. F. Kuech
Keyword(s):  
Fermi Level ◽  
Photoemission Spectroscopy ◽  
Ambient Conditions ◽  
Surface Band ◽  
Band Bending ◽  
Term Stability ◽  
Long Term Stability ◽  
Synchrotron Radiation Photoemission ◽  
Surface Fermi Level

AbstractSelenium disulfide surface treatment can unpin the surface Fermi-level on n-GaAs (100) surfaces, resulting in a reduction in the surface band bending. The long-term stability of the surface Fermi-level unpinning has been studied using photoreflectance spectroscopy under room ambient conditions. Our results show that the SeS2-treated n-GaAs (100) surface is stable up to four months with negligible shift in the surface Fermi-level being noted. The mechanism of the long-term stability is attributed to the layered surface structure formed on the SeS2-treated n- GaAs (100) surface. The chemical structure of the passivated surface was determined by synchrotron radiation photoemission spectroscopy. The outermost layer of sulfur and arsenicbased sulfides and selenides may protect the electronic passivating layer, which consists of gallium-based selenides, from interaction with the atmosphere.

scholarly journals Long-Term Stability of Lorazepam in Sodium Chloride 0.9% Stored at Different Temperatures in Different Containers

2019 ◽  
Vol 55 (3) ◽  
pp. 188-192
Author(s):  
M. L. Colsoul ◽  
A. Breuer ◽  
N. Goderniaux ◽  
J. D. Hecq ◽  
L. Soumoy ◽  
...  
Keyword(s):  
Time Management ◽  
High Performance ◽  
Room Temperature ◽  
Color Change ◽  
Storage Period ◽  
Term Stability ◽  
Long Term Stability ◽  
Glass Bottles ◽  
The Stability

Background and Objective: Infusion containing lorazepam is used by geriatric department to limit anxiety disorders in the elderly. Currently, these infusions are prepared according to demand by the nursing staff, but the preparation in advance in a centralized service could improve quality of preparation and time management. The aim of this study was to investigate the long-term stability of this infusion in polypropylene syringes stored at 5 ± 3°C. Then, results obtained were compared with stability data of lorazepam in syringes stored at room temperature, glass bottles at 5 ± 3°C, and glass bottles at room temperature. Method: Eight syringes and 6 bottles of infusion were prepared by diluting 1 mL lorazepam 4 mg in 23 mL of NaCl 0.9% under aseptic conditions. Five syringes and 3 bottles were stored at 5 ± 3°C and 3 syringes and 3 bottles were stored at room temperature for 30 days. During the storage period, particle appearance or color change were periodically checked by visual and microscope inspection. Turbidity was assessed by measurements of optical density (OD) at 3 wavelengths (350 nm, 410 nm, 550 nm). The stability of pH was also evaluated. The lorazepam concentrations were measured at each time point by high-performance liquid chromatography with ultraviolet detector at 220 nm. Results: Solutions were physically unstable in syringes at 5 ± 3°C after 4 days: crystals and a drop of OD at 350 nm were observed. However, pH was stable. After 2 days, solutions were considered as chemically unstable because a loss of lorazepam concentration higher than 10% was noticed: the lower 1-sided confidence limit at 95% was below 90% of the initial concentration. To assess temperature and polypropylene influence, results were compared with those obtained for syringes at room temperature and bottles at 5 ± 3°C and room temperature. Precipitation, drop of OD at 350 nm, and chemical instability were observed in all conditions. Conclusion: Solutions of lorazepam were unstable after 2 days in syringes at 5 ± 3°C. Preparation in advance appears, therefore, not possible for the clinical use. Storage conditions (temperature and form) do not improve the stability.

Strategic improvement of the long-term stability of perovskite materials and perovskite solar cells

2016 ◽  
Vol 18 (39) ◽  
pp. 27026-27050 ◽  
Author(s):  
Tingting Xu ◽  
Lixin Chen ◽  
Zhanhu Guo ◽  
Tingli Ma
Keyword(s):  
Solar Cells ◽  
Theoretical Calculations ◽  
Perovskite Solar Cells ◽  
Experimental Tests ◽  
Comprehensive Overview ◽  
Term Stability ◽  
Long Term Stability ◽  
Perovskite Materials ◽  
The Stability

This review provides a comprehensive overview of the recent strategies aimed at enhancing the long-term stability of perovskite materials and perovskite solar cells (PSCs). It also extensively discusses the stability problem of perovskite materials and PSCs from perspectives of experimental tests and theoretical calculations.

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