Photonic and Electronic Properties of Fluoride Materials

Progress in Fluorine Science Series

Alain Tressaud, Kenneth R. Poeppelmeier

• Publisher: Elsevier
• Year: 2016
• Print ISBN: 9780128016398
• eBook ISBN: 9780128017951
• Topic: Physical Sciences
• Subtopic: Inorganic Chemistry

Photonic and Electronic Properties of Fluoride Materials: Progress in Fluorine Science, the first volume in this new Elsevier series, provides an overview of the important optical, magnetic, and non-linear properties of fluoride materials. Beginning with a brief review of relevant synthesis methods from single crystals to nanopowders, this volume offers valuable insight for inorganic chemistry and materials science researchers.Edited and written by leaders in the field, this book explores the practical aspects of working with these materials, presenting a large number of examples from inorganic fluorides in which the type of bonding occurring between fluorine and transition metals (either d- or 4f-series) give rise to peculiar properties in many fundamental and applicative domains.This one-of-a-kind resource also includes several chapters covering functional organic fluorides used in nano-electronics, in particular in liquid crystal devices, in organic light-emitting diodes, or in organic dyes for sensitized solar cells.The book describes major advances and breakthroughs achieved by the use of fluoride materials in important domains such as superconductivity, luminescence, laser properties, multiferroism, transport properties, and more recently, in fluoro-perovskite for dye-sensitized solar cells and inorganic fluoride materials for NLO, and supports future development in these varied and key areas.The book is edited by Alain Tressaud, past chair and founder of the CNRS French Fluorine Network. Each book in the collection includes the work of highly-respected volume editors and contributors from both academia and industry to bring valuable and varied content to this active field. - Provides unique coverage of the physical properties of fluoride materials for chemists and material scientists - Begins with a brief review of relevant synthesis methods from single crystals to nanopowders - Includes valuable information about functional organic fluorides used in nano-electronics, in particular in liquid crystal devices, in organic light-emitting diodes, or in organic dyes for sensitized solar cells

1

Introduction to the Series “Progress in Fluorine Science”

A. Tressaud     ICMCB-CNRS, University of Bordeaux, Pessac, France

The history of science has been currently illustrated by a succession of breakthroughs and regressions. Karl Popper postulated that science goes forward through a process of “conjectures and refutations,” meaning that a theoretician should develop a theory, and an empirical scientist should try to test it to refutation. If the theory cannot be properly tested by science, this means that this proposal cannot be called scientific. One of the major points of Popper's postulates was establishing that science is not infallible, and that well-established scientific paradigms may often follow a wrong path, generating incorrect theories. This is true also for the behavior of new materials: the validity of their initially stated “outstanding” properties should be tested in the light of multidisciplinary approaches: purely scientific of course, but also arising from many other aspects: environmental, statistic, economic, sociologic, and even psychologic.

It can be put forward that fluoride products have followed similar schemes. During the last century, they have been in several occasions at the origin of huge discoveries for science and mankind. This is, for instance, the case of the use of fluoride melts to promote the aluminum production, the replacement of ammonia by so-called “freons” as industrial refrigerants, the discovery of Teflon^® and fluoropolymers. The last part of the 20th century has been illustrated by the rise of functionalized fluorinated molecules and by their beneficial aspects in agriculture, pharmacy, medicine, and biomedical sciences. One of the best examples is the use of ¹⁸F-labeled molecules for positron emission tomography. This imaging technique, which is now proposed in many hospitals and medical centers, allows the detection with a very high accuracy of the proliferation of cancer cells in the body via metastasis process and is thus able to propose therapy solutions at the early stage of the disease.

In these last decades, the development and applications of new materials have been rightly influenced by their effect on our environment. In this scope, although the benefits of fluoride compounds for our society are evident in many fields, the drawbacks caused to our environment by some of these products should not be underestimated. This dual aspect has also peripheral beneficial aspects because it compels teams dealing with fluoride products to launch great challenges for finding solutions able to overcome these problems, as shown below with a couple of examples.

• Nowadays, the ozone-depleting substances such as chlorofluorocarbons (CFCs) and hydrochlorofluorocarbons (HCFCs) are banned, and new replacement compounds with lower global warming potential are proposed, such as hydro-fluoro-oléfines (HFO). Fluorinated HFO-1234yf (2,3,3,3-tetrafluoropropene) is today a good example suitable for automobile refrigeration.

• Fluorosurfactants are essential in chemistry, biochemistry, and biotechnology. These species may act as detergents, wetting agents, emulsifiers, dispersants, and foaming agents: aqueous film-forming foams are among the most popular fire-fighting foams used for liquid fuel fires. However, since some of these species, such as perfluorooctanesulfonic acid (PFOS) and perfluorooctanoic acid (PFOA), characterized by long carbon chains, exhibit with a widespread occurrence in the blood of populations and wildlife, they have been judged as persistent organic pollutants by the Stockholm Convention. Consequently, the manufacturing and release to the environment of PFOS and PFOA is suspended by 2015. In order to take into account this regulation, companies are now manufacturing fluorosurfactants based upon four-carbon chains, as in perfluorobutanesulfonic acid, instead of longer chains. Multiple studies have indicated that perfluorobutanesulfonic acid (PFBS) as substitute, is neither toxic nor bioaccumulative.

As these examples demonstrate, the global socioeconomic issues associated with a discovery cannot be assessed immediately after the discovery. A true evaluation can only be made after a period of time; once scientists have been able to incorporate accumulated experimental data, including all effects of these new compounds on the environment, nature, human beings, and all life that is present on our planet.

The new series of book Progress in Fluorine Science aims to provide useful information based on emerging trends and research in the fields of physics, chemistry, biology of fluoride compounds and to highlight possible applications. Several volumes are expected to bring relevant information in the concerned fields from worldwide contributions proposed from both academia and industry.

Many research fields and applications are indeed impacted by the strategic importance of fluoride materials, or by the use of functionalization processes using fluorination treatments. It is indeed possible to find high-technology fluorine-based products as components in many industrial applications: microelectronics, microphotonics, fluorescent chemical sensors, solid-state lasers, nonlinear optics, optical fibers, special glasses, solar cells, energy storage and conversion, catalysis, textile, cosmetics, plastics, domestic wares, building, automotive, drugs and pharmaceuticals, biomedical materials, prostheses, medicinal and molecular imaging, agrochemistry, superhydrophobic coatings, surfactants, antifire products, etc. Most of these outstanding applications can be correlated to the exceptional electronic properties of the element “fluorine,” yielding almost unique types of bonding with the other elements. One of the novelties of this book series is to present, in an individual volume, different aspects of the chemistry and physics of a particular group of fluorine or fluoride compounds. Depending of the subject, the chapters will be specifically focused on inorganic, organic, or polymeric materials and will deal with synthetic pathways, physical–chemical characterizations, and finally applications and issues. The individual volumes of Progress in Fluorine Science are thematically independent, comprehensively addressing topical problems in both the science and applications of fluorinated compounds.

The goals of this series are to point out most important features and breakthroughs that have been obtained during this last decade in several key topics of fluorine-related fields. Some outstanding applications of fluorinated materials can be indeed correlated to the unique electronic properties of fluorine and derived materials with respect of other types of materials. In each volume, the interconnections between these different types of compounds will be highlighted with respect to one or several specific aspects and properties: physical–chemical behavior, synthesis routes and methodology, applications. The multiple facets of fluorinated compounds will be illustrated by classes of materials ranging from inorganic materials: eg, ceramics, inorganic nanopowders, nanostructured glasses, coordination complexes, fluorinated nematic liquid crystals, fluoropolymers, organic fluorocompounds, biomaterials, or perfluorinated organic molecules.

The series is composed for the moment of three titles to be appearing soon, each of them having its own editors. It should be noted that these titles and fields have been chosen because of the lack of books currently available on such topics. It can be anticipated that further volumes might deal with Biologically active fluorinated compounds, or with Fluorosurfactants in Industry and Biomedical Sciences, with recognized experts as editors. The first three titles of the series will be:

• Photonic & Electronic Properties of Fluoride Materials, Editors: A. Tressaud, CNRS, Bordeaux, France & K. Poeppelmeier, NW Univ. Evanston, USA;

• New Forms of Fluorinated Carbon, Editors: O. Boltalina, Univ. Colorado, USA & T. Nakajima, AIT, Toyota, Japan;

• Synthesis & Reactivity in Fluorinated Media, Editors: H. Groult, UPMC, Paris, F. Leroux, Joint Bayer-CNRS Lab., Strasbourg, & A. Tressaud, CNRS, Bordeaux, France.

In the present first volume, the relationships between structural aspects and physical properties will cover optical properties (luminescence, laser, upconversion, UV absorbers, frequency doubling), high-T_c superconductivity, ferro-, ferri-, and molecular magnetisms, multiferroism, ferroelectricity, ionic conduction mechanisms, ab-initio calculations. Important potential applications of the final products will be investigated in photonics: (organic) light-emitting diodes, liquid crystal displays, dye-sensitized solar cell, transparent conducting films, solid-state lasers, nonlinear optics, microelectronics and molecular electronics, imaging devices, electrodes and electrolytes for energy storage and conversion, etc.

It should be anticipated that volume 2 will cover fundamental research and emerging applications of fluorinated compounds of new carbon species such as fullerenes, carbon nanotubes, polycyclic aromatic molecules, carbon nanofibers, and graphene. Applications of these functional materials range from energy storage and energy conversion devices, molecular electronics, photonics, and lubricants.

Volume 3 will focus on the outstanding character of fluorine and fluorinated compounds, through examples taken from all classes of fluorine compounds which illustrate the extreme reactivity of fluorinating media and the peculiarity of their synthetic routes. Among topics to be addressed in the volume are supramolecular chemistry, fluoroorganics, asymmetric syntheses, use of Ruppert–Prakash reagent, CHF₃-based chemistry, fluorous media, photoredox catalysis, fluorosurfactants, synthesis in medicinal chemistry and biology, telomerization processes, photochemical and aHF routes to noble gas fluorocompounds, microwave-enhanced route, sol-gel reactions, superacidic media, ionic liquids, fluorine in the nuclear energy cycle, electrodes and electrolytes for energy storage devices, thin layers, surface modifications, etc.

Therefore the wide scope of entries occurring in this book series—ranging from new synthetic routes, physical and chemical characterizations to applications—will illustrate how fluorides and fluorinated compounds have strong positive impacts on various aspects of modern life.

Finally, I am pleased to thank the members of the “Fluorine pole” of ICMCB-CNRS and also my colleagues of the CNRS “French Fluorine Network” for many exchanges, longstanding friendship, constant support, and well-disposed critical scrutiny of my works during the past decades.

Pessac, October 2015.

Part One

Synthesis

Outline

2. Elaboration of Nanofluorides and Ceramics for Optical and Laser Applications

2

Elaboration of Nanofluorides and Ceramics for Optical and Laser Applications

P.P. Fedorov, S.V. Kuznetsov, and V.V. Osiko Prokhorov General Physics Institute, Russian Academy of Sciences, Moscow, Russia

Abstract

Coprecipitation of nanofluorides in MF₂-RF₃ and NaF-RF₃ (M = Ca, Sr, Ba; R = rare earth elements) results in the formation of nonequilibrium phases with wide areas of homogeneity. Detailed studies of such NaYF₄-, CaF₂-, SrF₂-, and LaF₃-type phases, coactivated by Yb and Er dopants and used as upconversion luminophores, and conditions of their formation allowed preparation of the materials with more than 5% luminescence energy yields. Laser-ceramic specimens of the aforementioned compositions, which were prepared by the hot forming of the crystals, exhibited the spectral and lasing properties similar to that of the single crystal materials. BaF₂·HF hydrofluoride and Sr_1−x−yR_x(NH₄)_yF_2+x−y solid solutions have been est...

Table of contents

• Cover image
• Title page
• Table of Contents
• Copyright
• List of Contributors
• Foreword
• 1. Introduction to the Series “Progress in Fluorine Science”
• Part One. Synthesis
• Part Two. Optical Properties
• Part Three. Magnetic Properties
• Part Four. Non-linear Properties
• Part Five. Superconductor Properties
• Part Six. Ionic Conductors
• Index