Search query: Focus on properties and applications of perovskites

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abstract: Missouri University of Science and Technology, USA 2 Tsinghua University, People's Republic of China University of Rennes 1, France E mail: doganf@mst.edu, honglin@mail.tsinghua.edu.cn, maryline.guilloux viry@univrennes1.fr and octavio. pena@univ rennes1.fr Perovskite materials with the same crystal structure as CaTiO3 exhibit intriguing and unusual physical properties that have been extensively studied for both practical applications and theoretical modeling. From the discovery of ceramic high temperature superconductors to the organic inorganic semiconductors for high efficiency photovoltaics, the materials science and applications of perovskites have been a very broad research area open to many revolutionary discoveries for new device concepts. The impressive range of structure and property interplay of perovskites makes them an excellent research field for studies in materials science, physics and solid state chemistry. Structurally, such materials form various crystals including oxide and organometallic perovskites, spinels, and pyrochlores, to name just a few. Many different types of lattice distortions can occur owing to the flexibility of bond angles within the ideal perovskite structure. A broad range of novel functional materials and device concepts can be envisaged through fundamental understanding of the relationships between the structural and chemical compatibility, thermal stability, solid solubility and lattice strain. In this focus issue of Science and Technology of Advanced Materials, we present articles that cover a wide range of topics on perovskites, which include ferroelectric, dielectric, pyroelectric, piezoelectric, magnetic, catalytic, photovoltaic and electronic conduction properties. While this focus issue may not exhaust the many aspects of perovskite materials, it does highlight our fundamental understanding and underscore many exciting developments in this field. We hope that these articles will stimulate more interest in perovskites and help readers better understand some important scientific and technological issues related to perovskite materials. Special thanks are due to the authors and manuscript reviewers. Without their efforts, this focus issue would not have been completed.
author_names: Fatih Dogan

Hong Lin

Maryline Guilloux-Viry

Octavio Pena
title: Focus on properties and applications of perovskites
venue: Science and technology of advanced materials
year: 2015

abstract: Due to their attractive optoelectronic properties, metal halide APbI3 perovskites employing formamidinum (FA+ as A cation are presently the focus of intense research, The superior chemical and thermal stability of FA+ cations renders a FAPbI3 more suitable for solar cell applications than methylammonium lead iodide (MAPbI3) However, its spontaneous conversion to the yellow non perovskite phase (d FAPbI3) under ambient conditions poses a serious challenge for practical applications. Here, we report on the stabilization of the desired a FAPbI3 perovskite phase by protecting it with a two dimensional (2D) IBA2FAPb2I7 (IBA iso butylammonium overlayer, formed via stepwise annealing. Remarkably, the a FAPbI3/IBA2FAPb2I7 based perovskite solar cell (PSC) reached a high power conversion efficiency (PCE) of close to 23% In addition, it showed excellent operational stability, retaining ~85% of its initial efficiency under severe combined heat and light stress, i.e. simultaneous exposure with maximum power tracking to full simulated sunlight at 80 degC over a period of 500 h.
author_names: Yuhang Liu

Seckin Akin

Alexander Hinderhofer

Felix Thomas Eickemeyer

Hongwei Zhu

Ji-Youn Seo

Jiahuan Zhang

Frank Schreiber

Haowen Zhang

Shaik Mohammed Zakeeruddin

Anders Hagfeldt

M Ibrahim Dar

Michael Gratzel
title: Stabilization of highly efficient and stable phase pure FAPbI3 Perovskite Solar Cells by Molecularly Tailored 2D Overlayers.
venue: Angewandte Chemie
year: 2020

abstract: Perovskite thin films possess excellent light absorption and light emission properties, as well as a high defect tolerance and high charge carrier mobilities [1] These properties founded their rapid development in solar cell applications and established this new class of materials as a strong candidate for solution processed light emitting applications and on chip laser sources [2] So far, the focus has been on investigating the laser behaviour under short pulsed excitation, given the laser death phenomenon observed after a few hundreds of nanoseconds of excitation [3] Clear CW lasing in perovskites still remains a challenge: It was only observed in a single cation perovskite at a specific temperature of 100 K, where the optical gain originates from small inclusions of a pump induced crystal phase [3] an unviable approach for practical applications. In contrast, we found that sustained CW operation is possible over a temperature range of ~80 130 K if the methylammonium (MA) cation is partially replaced by formamidinium (FA) and Caesium.
author_names: Isabel Allegro

Philipp Brenner

Ofer Bar-On

Marius Jakoby

Bryce Sydney Richards

Ulrich Wilhelm Paetzold

Ian A Howard

Jacob Scheuer

Uli Lemmer
title: Continuous Wave Amplified Spontaneous Emission in Phase Stable Triple Cation Lead Halide Perovskite Thin Films
venue: 2019 Conference on Lasers and Electro Optics Europe European Quantum Electronics Conference (CLEO/Europe EQEC)
year: 2019

abstract: Oxides are versatile materials with applications in many different research fields; especially those related to clean energy technologies, such as fuel cells, batteries and solar panels. Many functional properties of these materials derive from lattice imperfections, or defects, and a lot of effort has been put into fine tuning these materials by modifying their structure on the atomic scale. This lays the foundation for this thesis, where the aim has been to explain the underlying mechanisms of properties in a selection of oxides, mainly those with the perovskite structure AB O3, by studying a variety of different defect species: oxygen vacancies, protons and hydride ions, acceptor dopants, electron and hole polarons, and grain boundaries (GBs) The methodology employed here constitutes a set of first principles methods, mainly different flavors of density functional theory (DFT) but also perturbation theory within the G0W0 approximation, assisted by thermodynamic modeling. The major part of the thesis is focused on defects in BaZrO3, an oxide that when acceptor doped and exposed to water acts as one of the most promising ceramic proton conductors by combining high bulk conductivity with high stability. The total proton conductivity in this material is, however, limited by high impedance at GBs due to the formation of space charges at these interfaces. This issue is addressed in four of the appended papers, which include studies on several different GBs as well as a comparison with GBs in the similar perovskite BaCeO3. Acceptor doped BaZrO3 is also a p type conductor under oxidizing conditions and this serves as the motivation for two papers, which address the methodology required for a proper theoretical description of holes in these materials. The final paper on BaZrO3 sets out to describe the chemical expansion the material exhibits upon hydration. The work extends beyond conventional ceramic proton conductors with a study on the novel oxyhydride material BaTiO3 xHx, where the electronic and vibrational properties of hydride ions are investigated. Finally, the thesis is concluded with a study of the oxygen vacancy in a set of binary and ternary oxides, where the aim is to show the general behavior this defect displays in these materials despite the fact that both the electronic and ionic structure varies significantly between the different compounds.
author_names: Anders Lindman
title: On the defective origin of conductive and structural properties of oxides: insights from first principles
year: 2017

abstract: Lead free piezoelectric ceramics with the formula of (1 x)Bi0.5(Na0.80K0.20)0.5TiO3 xLiNbO3 or (1 x)BNKT xLN system, when x 0, 0.01, 0.02, 0.03, 0.04, 0.05 and 0.06 mol fraction, were fabricated by a conventional mixed oxide method and sintered at the temperature of 1100degC for 2 h. All ceramics were focused in terms of phase, microstructure, dielectric, ferroelectric and piezoelectric properties. All samples have the density ranging of 5.50 5.66 g/cm3. X ray diffraction pattern exhibited a single perovskite structure without any secondary phases. Scanning electron micrographs indicated a cubic like grain shape occurred for all compositions with average grain size of 1.11 1.09 mm. The addition of LN also improved dielectric properties of BNKT ceramic. The maximum dielectric constant measured at room temperature was 1830 for BNKT 0.03LN sample.
author_names: Pimpilai Wannasut

Anucha Watcharapasorn

Pharatree Jaita

Sukanda Jiansirisomboon
title: Microstructure and electrical properties of (1 x)Bi0.5(Na0.80K0.20)0.5TiO3 xLiNbO3 lead free piezoelectric ceramics
venue: 2015 Joint IEEE International Symposium on the Applications of Ferroelectric (ISAF) International Symposium on Integrated Functionalities (ISIF) and Piezoelectric Force Microscopy Workshop (PFM)
year: 2015

abstract: We aimed to perform a comprehensive systematic review of the existing ataxia scales. We described the disorders for which the instruments have been validated and used, the time spent in its application, its validated psychometric properties, and their use in studies of natural history and clinical trials. A search from 1997 onwards was performed in the MEDLINE, LILACS, and Cochrane databases. The web sites ClinicalTrials.gov and Orpha.net were also used to identify the endpoints used in ongoing randomized clinical trials. We identified and described the semiquantitative ataxia scales (ICARS, SARA, MICARS, BARS) semiquantitative ataxia and non ataxia scales (UMSARS, FARS, NESSCA) a semiquantitative non ataxia scale (INAS) quantitative ataxia scales (CATSYS 2000, AFCS, CCFS and CCFSw, and SCAFI) and the self performed ataxia scale (FAIS) SARA and ICARS were the best studied and validated so far, and their reliability sustain their use. Ataxia and non ataxia scores will probably provide a better view of the overall disability in long term trials and studies of natural history. Up to now, no clear advantage has been disclosed for any of them; however, we recommend the use of specific measurements of gait since gait ataxia is the first significant manifestation in the majority of ataxia disorders and comment on the best scales to be used in specific ataxia forms. Quantitative ataxia scales will be needed to speed up evidence from phase II clinical trials, from trials focused on the early phase of diseases, and for secondary endpoints in phase III trials. Finally, it is worth remembering that estimation of the actual minimal clinically relevant difference is still lacking; this, together with changes in quality of life, will probably be the main endpoints to measure in future therapeutic studies.
author_names: Jonas Alex Morales Saute

Karina C Donis

Carmen Serrano-Munuera

David Genis

Luis Torres Ramirez

Pilar Mazzetti

Luis Velazquez Perez

Pilar Latorre

Jorge Sequeiros

Antoni Matilla-Duenas

Laura Bannach Jardim

On behalf of the Iberoamerican Multidisciplinary Netw Group
title: Ataxia Rating Scales Psychometric Profiles, Natural History and Their Application in Clinical Trials
venue: The Cerebellum
year: 2011

abstract: IntroductionAssessing the significance of pharmacist interventions (PIs) is essential to demonstrate the added value of pharmacists. Methods and tools for assessing the potential significance of PIs are diverse and their properties are questionable.ObjectivesWe aimed to systematically review the tools available to assess the potential significance of PIs.MethodsWe conducted a systematic search for English or French language publications from 1986 to 2013 in PubMed, PsycINFO, PASCAL, and CINAHL. Studies were screened by two independent reviewers based on inclusion/exclusion criteria and were abstracted for content, structure of tools, and validation process.ResultsOf 873 citations screened, 82 distinct tools were identified from 133 studies. While clinical aspects were often defined quite clearly, terminology regarding humanistic, economic, and process related aspects of PIs was omitted, incomplete, or ambiguous in most tools. The probabilities of consequences of PIs/drug related problems were evaluated in 20/82 tools. Few tools simultaneously measured economic, clinical, humanistic, and process related variables. Structure of the tools varied from an implicit, mono dimensional tool to an explicit, multi dimensional algorithm. Validation processes were diverse in terms of quantification and number of raters, rating method, and psychometric parameters. Of 133 identified studies, there was limited evidence of validity (8/133, 6.0 inter rater reliability (49/133, 36.8 and intra rater reliability (2/133, 1.5 .ConclusionsThe majority of tools focused primarily on assessing clinical aspects and failed to detect comprehensive impacts. The heterogeneity of tools and assessment processes hindered our ability to synthesize the results of evaluations. Limited results for their validity and reliability cast doubt on the credibility of this methodology for justification of the value of PIs. Recommendations for development of tools with optimal theoretical, pragmatic, and psychometric properties are proposed.
author_names: Thi Ha Vo

Bruno Charpiat

C Catoire

Michel Juste

Renaud Roubille

F X Rose

Sebastien Chanoine

Jean-Luc Bosson

Ornella Conort

Benoit Allenet

Pierrick Bedouch

On Behalf of the Working Group "Standardizing and Dem Pharmacy
title: Tools for Assessing Potential Significance of Pharmacist Interventions: A Systematic Review
venue: Drug Safety
year: 2015

abstract: Materials that exhibit colossal magnetoresistance (CMR) are currently the focus of an intense research effort, driven by the technological applications that their properties suggest. Using the angular correlation of photons from electron positron annihilation, we present a first view of the Fermi surface of a material that exhibits CMR, supported by `virtual crystal' electronic structure calculations. The Fermi surface is shown to be sufficiently cubic in nature that it is likely to support nesting.
author_names: Eric A Livesay

Roy Neil West

Stephen B Dugdale

Gilles Santi

The University of Texas at Arlington

University of Bristol

University of Geneva
title: Fermi surface of the colossal magnetoresistance perovskite La0.7Sr0.3MnO3
year: 1998

abstract: Perovskite solar cells are notorious for exhibiting transient behaviour not seen in conventional inorganic semiconductor devices. Significant inroads have been made into understanding this fact in terms of rapid ion migration, now a well established property of the prototype photovoltaic perovskite MAPbI$_3$ and strongly implicated in the newer mixed compositions. Here we study the manifestations of ion migration in frequency domain small signal measurements, focusing on the popular technique of Electrical Impedance Spectroscopy (EIS) We provide new interpretations for a variety of previously puzzling features, including giant photo induced low frequency capacitance and negative capacitance in a variety of forms. We show that these apparently strange measurements can be rationalized by the splitting of AC current into two components, one associated with charge storage, and the other with the quasi steady state recombination current of electrons and holes. The latter contribution to the capacitance can take either a positive or a negative sign, and is potentially very large when slow, voltage sensitive processes such as ion migration are at play. Using numerical drift diffusion semiconductor models, we show that giant photo induced capacitance, inductive loop features, and low frequency negative capacitance all emerge naturally as consequences of ion migration via its coupling to quasi steady state electron and hole currents. In doing so, we unify the understanding of EIS measurements with the comparably well developed theory of rate dependent current voltage (I V) measurements in perovskite cells. Comparing the two techniques, we argue that EIS is more suitable for quantifying I V hysteresis than conventional methods based on I V sweeps, and demonstrate this application on a variety of cell types.
author_names: Daniel A Jacobs

Heping Shen

Florian Pfeffer

Jun Peng

Thomas P White

Fiona J Beck

Kylie R Catchpole Research School of Engineering

The Australian National University
title: The Two Faces of Capacitance: New Interpretations for Electrical Impedance Measurements of Perovskite Solar Cells and Their Relation to Hysteresis
year: 2018

abstract: 1.The national principle of exhaustion of exclusive trademark rights applies in combination with the principle of exhaustion of rights as regulated by international agreements, to which the Russian Federation is a party.2.A court may deny in full or in part the ordering of legal measures countering the importation into the territory of the Russian Federation without the consent of the trademark right holder of a specific quantity of goods, on which the trademark is affixed by the right holder himself or with his consent and which were legally put into circulation outside of the borders of the Russian Federation, in the cases, when due to the trademark right holder's unfair conduct the application upon his request of such legal consequences may create a threat upon the citizen's life and health, and other publicly significant interests.3.Moreover the observance by the trademark right holder of a regime of sanctions against the Russian Federation, which was adopted by any other State outside of the predetermined international legal procedure and in violation of multilateral international agreements, to which the Russian Federation is party, expressed in the attitude adopted by the right holder towards the Russian market, may be in itself considered as unfair behaviour.4.It is not envisaged to order against the importation into the territory of the Russian Federation without the consent of the trademark right holder of a quantity of goods on which the trademark is affixed by the right holder or with his consent, civil liability measures that are identical in terms of volume (gravity of the outcome) to those countering the importation of fake goods, unless in the circumstances of a specific dispute it leads to losses for the right holder, comparable to the losses suffered from the introduction in circulation of fake goods.5.Goods, bearing a trademark affixed by the right holder himself or with his consent, introduced into the territory of the Russian Federation without the consent of the right holder, may be removed from circulation and destroyed pursuant to the remedies countering the infringement of an exclusive trademark right only in the event of their inadequate quality and (or) in order to ensure safety, protection of people's lives and health, nature and cultural property.
author_names: Arts 1252 para 4 1487 1515 paras 1 and 2 Agreement on "PAG" LLC v Sony Corporation Civil Code of the Ru
title: "PAG LLC v. Sony"
year: 2018