scholarly journals Mapping temperature-dependent energy–structure–property relationships for solid solutions of inorganic halide perovskites

2020 ◽  
Vol 8 (47) ◽  
pp. 16815-16825
Author(s):  
Jack Yang
Keyword(s):  
Machine Learning ◽  
Solid Solutions ◽  
Finite Temperature ◽  
Energy Structure ◽  
Structure Property ◽  
Temperature Dependent ◽  
Unsupervised Machine Learning ◽  
Structure Property Relationships ◽  
Electronic Dynamics ◽  
Halide Perovskites

We explored how lead/tin mixing affects the finite-temperature stabilities, atomistic and electronic dynamics of inorganic halide perovskites, with the aid of unsupervised machine learning and the recently devised anharmonicity score.

scholarly journals Mapping Temperature-Dependent Energy-Structure-Property Relationships for Solid Solutions of Inorganic Halide Perovskites

2020 ◽  
Author(s):  
Jack Yang
Keyword(s):  
Solid Solutions ◽  
Band Gaps ◽  
Energy Structure ◽  
Material Research ◽  
Structure Property ◽  
Temperature Dependent ◽  
Orbital Interactions ◽  
Structure Property Relationships ◽  
Data Driven Approach ◽  
Halide Perovskites

Formation of solid solutions with complex compositions has been exhaustively adopted in material research for improving chemical and physical properties. This is also the true for halide perovskites, in the hope of further enhancing their stabilities and reducing the toxicities in lead-containing compounds. Replacement of lead with tin, even partially, is a route to achieve the latter goal. However, this has to be compromised with reduction in band gaps as well as structural stabilities. High-throughput statistical samplings over different configurations for random solid solutions have played pivotal roles in guiding the chemical designs of halide perovskite with better stabilities while retaining high photovoltaic efficiencies, but it remains challenging to intuitively and comprehensively understand the intriguing energy-structure-property (ESP) relationships in solid solutions encompassing multiple degrees-of-freedoms. In this work, first--principle dynamic and electronic structure calculations are performed across 51 different compositions of Cs(Pb$_{x}$Sn$_{1-x}$)X$_{3}$ (X=Cl, Br and I), to systematically reveal the compositional and temperature dependent stabilities, vibrational anharmonicities and band gaps in solid solutions of halide perovskites. This is enabled, in particular, by applying a recently proposed `anharmonicity score' that provides a single numerical metric to characterise the structural dynamics in a multi-atomic system. Further combination with unsupervised machine-learning enable us to produce an ESP map to visually correlate the anharmonicity score with structural distortions and energies. However, temperature-dependent variations in band gap energies, which strongly depend on orbital interactions in metal-halide octrahedra, do not necessarily follow the same trend as anharmonicity scores. This work represents our latest developments in applying data--driven approach to establish ESP relationships for guiding the future designs of functional perovskites.

Mapping Temperature-Dependent Energy-Structure-Property Relationships for Solid Solutions of Inorganic Halide Perovskites

2020 ◽  
Author(s):  
Jack Yang
Keyword(s):  
Solid Solutions ◽  
Band Gaps ◽  
Energy Structure ◽  
Material Research ◽  
Structure Property ◽  
Temperature Dependent ◽  
Orbital Interactions ◽  
Structure Property Relationships ◽  
Data Driven Approach ◽  
Halide Perovskites

Formation of solid solutions with complex compositions has been exhaustively adopted in material research for improving chemical and physical properties. This is also the true for halide perovskites, in the hope of further enhancing their stabilities and reducing the toxicities in lead-containing compounds. Replacement of lead with tin, even partially, is a route to achieve the latter goal. However, this has to be compromised with reduction in band gaps as well as structural stabilities. High-throughput statistical samplings over different configurations for random solid solutions have played pivotal roles in guiding the chemical designs of halide perovskite with better stabilities while retaining high photovoltaic efficiencies, but it remains challenging to intuitively and comprehensively understand the intriguing energy-structure-property (ESP) relationships in solid solutions encompassing multiple degrees-of-freedoms. In this work, first--principle dynamic and electronic structure calculations are performed across 51 different compositions of Cs(Pb$_{x}$Sn$_{1-x}$)X$_{3}$ (X=Cl, Br and I), to systematically reveal the compositional and temperature dependent stabilities, vibrational anharmonicities and band gaps in solid solutions of halide perovskites. This is enabled, in particular, by applying a recently proposed `anharmonicity score' that provides a single numerical metric to characterise the structural dynamics in a multi-atomic system. Further combination with unsupervised machine-learning enable us to produce an ESP map to visually correlate the anharmonicity score with structural distortions and energies. However, temperature-dependent variations in band gap energies, which strongly depend on orbital interactions in metal-halide octrahedra, do not necessarily follow the same trend as anharmonicity scores. This work represents our latest developments in applying data--driven approach to establish ESP relationships for guiding the future designs of functional perovskites.

On the nature of the phase transitions of aluminosilicate perrhenate sodalite

2020 ◽  
Vol 235 (6-7) ◽  
pp. 213-223
Author(s):  
Hilke Petersen ◽  
Lars Robben ◽  
Thorsten M. Gesing
Keyword(s):  
Raman Spectroscopy ◽  
Phase Transitions ◽  
Decomposition Temperature ◽  
Second Phase ◽  
Structure Property ◽  
X Ray Diffraction ◽  
Temperature Dependent ◽  
Two Phase ◽  
Structure Property Relationships ◽  
Heat Capacity Measurements

AbstractThe temperature-dependent structure-property relationships of the aluminosilicate perrhenate sodalite |Na8(ReO4)2|[AlSiO4]6 (ReO4-SOD) were analysed via powder X-ray diffraction (PXRD), Raman spectroscopy and heat capacity measurements. ReO4-SOD shows two phase transitions in the investigated temperature range (13 K < T < 1480 K). The first one at 218.6(1) K is correlated to the transition of dynamically ordered $P\overline{4}3n$ (> 218.6(1 K) to a statically disordered (<218.6(1) K) SOD template in $P\overline{4}3n$. The loss of the dynamics of the template anion during cooling causes an increase of disorder, indicated by an unusual intensity decrease of the 011-reflection and an increase of the Re-O2 bond length with decreasing temperature. Additionally, Raman spectroscopy shows a distortion of the ReO4 anion. Upon heating the thermal expansion of the sodalite cage originated in the tilt-mechanism causes the second phase transition at 442(1) K resulting in a symmetry-increase from $P\overline{4}3n$ to $Pm\overline{3}n$, the structure with the sodalites full framework expansion. Noteworthy is the high decomposition temperature of 1320(10) K.

scholarly journals Classification of Platinum Nanoparticle Catalysts using Machine Learning

2020 ◽  
Author(s):  
Amanda J. Parker ◽  
George Opletal ◽  
Amanda Barnard
Keyword(s):  
Machine Learning ◽  
Hydrogen Oxidation ◽  
Pt Nanoparticles ◽  
Structure Property ◽  
Metallic Nanoparticle ◽  
Platinum Nanoparticle ◽  
Nanoparticle Catalysts ◽  
Structure Property Relationships ◽  
Multi Stage

Computer simulations and machine learning provide complementary ways of identifying structure/property relationships that are typically targeting toward predicting the ideal singular structure to maximise the performance on a given application. This can be inconsistent with experimental observations that measure the collective properties of entire samples of structures that contain distributions or mixture of structures, even when synthesized and processed with care. Metallic nanoparticle catalysts are an important example. In this study we have used a multi-stage machine learning workflow to identify the correct structure/property relationships of Pt nanoparticles relevant to oxygen reduction (ORR), hydrogen oxidation (HOR) and hydrogen evolution (HER) reactions. By including classification prior to regression we identified two distinct classes of nanoparticles, and subsequently generate the class-specific models based on experimentally relevant criteria that are consistent with observations. These multi-structure/multi-property relationships, predicting properties averaged over a large sample of structures, provide a more accessible way to transfer data-driven predictions into the lab.

Rational chemical doping of metal halide perovskites

2019 ◽  
Vol 48 (2) ◽  
pp. 517-539 ◽  
Author(s):  
Xinyuan Zhang ◽  
Lina Li ◽  
Zhihua Sun ◽  
Junhua Luo
Keyword(s):  
Metal Halide ◽  
Underlying Structure ◽  
Chemical Doping ◽  
Structure Property ◽  
Structure Property Relationships ◽  
Halide Perovskites

This review summarizes recent significant work on metal-halide doped perovskites, disclosing the underlying structure–property relationships to provide useful insights into their applications.

Cerium intermetallics CeTX – review III

2016 ◽  
Vol 71 (3) ◽  
pp. 165-191 ◽  
Author(s):  
Rainer Pöttgen ◽  
Oliver Janka ◽  
Bernard Chevalier
Keyword(s):  
High Pressure ◽  
Solid Solutions ◽  
Spectroscopic Data ◽  
Structure Property ◽  
The Third ◽  
Structure Property Relationships ◽  
High Pressure Studies ◽  
Hydrogenation Reactions ◽  
Cerium Intermetallics ◽  
Cerium Compounds

AbstractThe structure–property relationships of CeTX intermetallics with structures other than the ZrNiAl and TiNiSi type are systematically reviewed. These CeTX phases form with electron-poor and electron-rich transition metals (T) and X = Mg, Zn, Cd, Hg, Al, Ga, In, Tl, Si, Ge, Sn, Pb, P, As, Sb, and Bi. The review focusses on the crystal chemistry, the chemical bonding peculiarities, and the magnetic and transport properties. Furthermore 119Sn Mössbauer spectroscopic data, high-pressure studies, hydrogenation reactions and the formation of solid solutions are reviewed. This paper is the third of a series of four reviews on equiatomic intermetallic cerium compounds [Part I: R. Pöttgen, B. Chevalier, Z. Naturforsch. 2015, 70b, 289; Part II: R. Pöttgen, B. Chevalier, Z. Naturforsch. 2015, 70b, 695].

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