Materials Science: evolution and perspectives.

Materials Science: evolution and perspectives
José A. Varela
University of São Paulo State - UNESP
São Paulo State Funding Agency - FAPESP
11/13/2014
1
Copyright © 2014 José Arana Varela. All rights reserved.

Introduction
•World population growth is stretching the limits of the earth’s natural resources.
• New and effective ways to have Science and Technology to meet global goals of environmental, health and economic development (recycling is also important!).
• Expanding energy needs while reducing gas emissions to minimize climate change is the biggest challenge.

Emission Control – Importance of Gas Sensors
Monitoring emission of toxic gases to the atmosphere is extremely important for the society.
Air pollution is mainly from Chemical Industries, Power Plants and Vehicles.

Those challenges need more collaboration among world scientists as well as an science more open.
Emission Control – Importance of Gas Sensors
 Solving these problems certainly involves the development of more efficient materials.

NO2 Levels Around the World

The American Ceramic Society
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Founded in 1898, The American Ceramic Society was formed at a convention of the National Brick Manufacturers’ Association in Pittsburgh, PA. It was there that several attendees banded together to talk about the scientific side of ceramics through a free exchange of ideas and research. Now the society has grown to more than 9,500 members and students with 30 percent of membership being internationally based in more than 60 countries.
Today, the Society is providing knowledge and forums to members who are shaping the way we think about materials science. From bricks to cell phones and appliances to space shuttle tiles and green technology.

American Society for Metals (ASM)
•ASM has been in existence, under various names, since 1913, when it began as a local club in Detroit called the Steel Treaters Club. During World War I, the Steel Treaters Club became the Steel Treating Research Society, with groups in Detroit, Chicago, and Cleveland. After World War I, the Chicago group seceded and formed the American Steel Treaters Society. In 1920 the local chapters were reunified into the new American Society for Steel Treating (ASST).[4] The society expanded its technical scope beyond steel during the 1920s. In 1933 it became the American Society for Metals (ASM). Gradually the society expanded its geographic scope beyond the U.S. and its technical scope beyond metals to include other materials It became known as ASM International in 1986.
• As of 2010, ASM claims 36,000 members worldwide.
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Polymeric Materials Science and Engineering – PMSE – Division of the ACS
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PMSE was founded in 1924 as the Paint and Varnish Division, and until 1983 was known as the Division of Organic Coatings and Plastics Chemistry of the American Chemical Society. Main materials interests: adhesives, biomedical polymers, composites, polymers for electronic applications, plastics, and many other areas of applied polymer science and technology in addition to traditional coatings-related topics.
PMSE is the Division of ACS that provides a forum for the exchange of technical information and fosters interactions in materials science and engineering for the global chemistry community.

Materials Societies
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Founded in 1983, the European Materials Research Society (E-MRS) now has more than 3,200 members from industry, government, academia and research laboratories, who meet regularly to debate recent technological developments of functional materials.
The Materials Research Society (MRS) was established in 1973 by a visionary group of scientists who shared the belief that their professional interests were broader in scope than existing single-discipline societies and that a new interdisciplinary organization was needed.
Over 16,000 materials researchers members from academia, industry and government from more than 80 countries.

Materials Societies
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The MRS-Japan (Materials Research Society of Japan) was founded in March 1989, based on the premises with interdisciplinary and multidisciplinary stances, after holding MRS International Conference on Advanced Materials at Sunshine City in Ikebukuro in May 1988.
IUMRS: INTERNATIONAL UNION OF MRS The International Union of Materials Research Societies was established in 1991 as an international association of technical groups or societies which have an interest in promoting interdisciplinary materials research.

Sociedade Brasileira de Pesquisa em Materiais
•Aos vinte seis dias do mês de junho de 2001, em Assembléia Geral de Constituição, os sócios-fundadores da Sociedade Brasileira de Pesquisa em Materiais, SBPMat, reuniram-se no Auditório do RioDatacentro da PUC-Rio.
•A mesa que conduziu a discussão foi presidida por Guillermo Solórzano (PUC-Rio) e constituída por Fernando Lázaro Freire Junior (PUC-Rio), Elisa Baggio Saitovich (CBPF), Moni Behar (UFRGS) e José Arana Varela (UNESP).
•I Encontro da SBPMat - Rio de Janeiro, 7-10 julho 2002.
•Constituido de 5 simpósios e um Workshop nos seguintes temas: materiais nanoestruturados, biomateriais, semicondutores, eletrocerâmica, filmes finos poliméricos e materiais particulados.
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Inorganic Functional Materials
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Structure of cubic BaTiO3.
The red spheres are O-2 centers,
blue are Ti4+ cations, and the green
spheres are Ba2+.
BaTiO3 is the most widely used ferroelectric material, and even sixty years after its discovery, it is the most important multilayer ceramic dielectric. BaTiO3 was discovered during World War II in 1941 and 1944 in the United States, Russia, and Japan. At least in the U.S.A., the research was accelerated because of the war. Barium titanate (BaTiO3) has been of practical interest for more than 60 years because of its attractive properties. BT has several application as dielectric, piezoelectric and wide band gap semiconductor ceramics. Can be used as transducers, ferroelectric memories, thermistors and self regulating electric heating systems.

ZnO varistor
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Surge Protector
Circuit protection
protect against excessive transient voltages

MRS Bulletin, Special Issue vol. 37, n. 4 (2012)
bulk recycling
Electric
cars
Water
purification
Energy
efficiency
CO2
mitigation
materials for sustainable development
Efficient
production
wind
solar
nuclear
coal
Complex product recycling

0%
10%
20%
30%
40%
50%
60%
Non-Renewable
Renewable
Energy sources in Brazil, 2009
Brazil: 47% of energy from renewable sources (2009); 18% from sugarcane
cane
18%
Renewables
Brazil 47%; World 13%; OECD 7.2%
C.H. Brito Cruz e Fapesp

The use of ethanol leads to low emissions

NANOSCIENCE
• Nanoscience and nanotechnology have opened many doors for solving key problems.
• Developing new smart materials is a multidisciplinary field and collaboration among scientists and engineers worldwide certainly will improve solutions for processing more efficient materials.
• In particular, the majority of Metal Oxide Semiconductor (MOS) are multifunctional and has been applied for many solutions
These include varistors, thermistors, sensors, memories, optical devices, among others.

Application of Metal Oxide Semiconductors
-Metal Oxide Semiconductor (MOS) has been applied to solve many societal problems including energy production and saving, environment control, health care, communication, water treatment, among others.
-Most of MOS are multifunctional and its application for a desirable solution depends on our knowledge of how to control optical and electrical properties by creating suitable chemical defects to achieve the desirable properties.
- Our fundamental knowledge on MOS has been substantially improved recently by means of increasing collaboration among scientists worldwide.
- Due to the complexity of the polycristalline MOS, many technological application of these materials depends on the chemical and physical theoretical understanding, achieved with more collaboration among Materials Scientists worldwide.

MOS Matrix
Material
Design
Tuning
Properties
Definition of the MO matrix for the desired application
Adjusting
additives,
morphology,
etc.
Material Processing
(bulk, thin films,
tape cast, etc.)
Microstructure
(density, porosity,
secondary phases,
etc.).
Powder Synthesis
(particle size, shape,
crystallization)

Have been commercially used for many applications
such as surge arrestors and in electric circuit protection.
• To improve the properties several additives have been used.
However, those additives may result in bismuth rich layer at grain boundaries,
which can decrease the stability of the Schottky barriers.
• To improve the stability of these Schottky barriers during operation,
there are two approaches: a) engineering of the grain boundaries by
optimization of composition and microstructure; b) finding another MOV system.
ZnO based Varistors

Grain boundary barrier by EFM
30% of the active interfaces 85% of the active interfaces
ZnO SnO2
M. Ramirez et al, J. Appl. Phys. 108(7) (2010) #074506
collaboration UNESP (Brazil) - INTEMA (Argentina)
Copyright © 2014 José Arana Varela.
All rights reserved.

EFM of MOV under different conditions
ZnO SnO2
Before degradation process
After DC degradation
After current pulses degradation
30%
85%
5%
85%
1%
5%
Ramirez M.A. et al J. Am. Cer. Soc 96(6)
(2013), 1801-9

GAS SENSORS
• Use of doped metal semiconductor oxide to create surface
defects (n or p) that favor the chemisorption of selective gas.
• The idea is that the proper dopant could increase or
decrease substantially the resistance of the semiconductor.
• Use of one or two dimensional MOS nanoparticles that
improve the exposure of the material surface.

Environment Control
4 S: Sensitivity, Selectivity, Speed & Stability
e
e
e
R/R
E
e
Ldep
New materials and structures

Sensor Characterization
MIT facility
•Multiplexed measurements of up to 8 samples simultaneously under equivalent experimental conditions.
•Software controls temperature, steps gas concentration, records transient response.
•DC resistance or impedance spectroscopy. .

SnO2
Sn3O4
SnO
Case Study: SnOx
SnO2: This n-type semiconductor is a basis for thousands of sensor studies; Other oxidation states result in metastable phases difficult to fabricate and rarely studied. Novel method enables synthesis and the study of these unusual materials. Unexpectedly high sensitivity is observed.

Micro Disks
Black Deposit
SnO single crystal
Disks: tetragonal SnO with large (001) surface
(110)
Orlandi M.O. et al, Crystal Growth & Design, 8, 1067, 2008.
Collaboration: UNESP (Brazil) and MIT (USA)

High Selectivity – Tin Oxides
Tin oxide (SnO2 NBs, SnO NBs and SnO Discs).

• Electrical FERROELECTRIC MEMORY
0 1 2 3 4 5 6 7 8 9 10
-10
-5
0
5
10
109%
90%
100 kHz
Pulso = 3V
SBT-Conv.-800oC/2h - ar
+Pr / -Pr (C/cm2)
Log 10 n (ciclos)
-150 -100 -50 0 50 100 150
-15
-10
-5
0
5
10
15
-5 -3 -2 0 2 3 5
Volts
SBT-Conv- 800oC/2h - ar
Antes da Fadiga
Após a Fadiga
Polarização (C/cm2)
Campo Elétrico (kV/cm)
/cm
kV/cm)
SrBi2Ta2O9 Thin Film
S.M. Zanetti et al, J. Eur. Ceram. Soc, 21(12),
(2001) 2199-06
Collab. UNESP (Brazil) - Un. Rennes (France)

Resistive Memory
Transition Metal Oxide Thin films for resistive memory

Cross-section and surface FE-SEM images showing the CCTO morphology of the
nanostructured film obtained at 300oC deposition temperature for 120 minutes.
CCTO Thin films
J.A. Varela et al, J. Am. Ceram. Soc. 93(1)51-54 (2010)
Collaboration: UNESP (Brazil) - IJS (Slovenia)

Image illustrating the Pt/CCTO/Pt MOM configuration used for the electrical characterization
of CCTO sputtered nanostructures grown at 300oC for 120 min. (compliance current = 1.0 μA)
I-V curve showing the hysteresis behavior of
an individual CCTO nanorod

Characteristic I-V curve of the micro-capacitors based on CCTO sputtered
nanorods deposited at RT for 15 min (compliance current = 10 μA).
Micro-capacitors display a resistive
memory phenomenon.
R Tararam et al, ACS Appl. Mater. & Interfaces 3(2), 500 (2011)
Collaboration: UNESP (Brazil) - Univ. Aveiro (Portugal)

Experimental and Theoretical Approach
J. Apl. Phys. 110, 043501 (2011) Collaboration: UNESP (Brazil) - U.Jaume I (Spain)
Presence of excited electronic state in CaWO4 crystals provoked by a tetrahedral distortion:

SUMMARY
•Enormous recent advances in the knowledge of MOS surface and grain boundary interaction with ambient gases for designing varistors and gas sensors. Degradation resistant varistors as well as Giant Chemo-Resistance SnO sensors have been recently demonstrated.
• However there is a lack of theoretical understanding of the mechanisms for high electronic defect states at the MOS surface, the key for future development of new sensors with high sensitivity, selectivity and stability.
•A deep understanding of the driving mechanism for resistive switching is required to optimize ReRAM devices for large scale production;
• Collaborations among Materials Scientists, Engineers, Chemists and Physicists worldwide are fundamental to solve many societal problems for sustainable development. Science Funding Agencies worldwide must provide the ways for these network formation.

How to Accelerate Materials Science Development in Brazil?
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11/13/2014
•Promoting meetings like this one for materials scientists coming from all of the world to discuss recent findings.
•Collaborations among scientists of Brazilian universities and well ranked universities all of the world.
•Agreement between Brazilian and Foreign Research Funding Agencies in countries with prestigious science.
•National policy to send Brazilian scientists to spend short or large period in international laboratories (for scientific meetings, research fellowship, fellowship for short stay, etc.) as well as to receive talented foreign young investigator to work in Brazilian laboratories.

International Collaboration Initiatives
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11/13/2014
National Program Science Without Borders – a joint program between two Ministries: Education and Science/Technology/ Innovation conducted by CNPq and CAPES.
FAPESP program for internationalization of science.
Objective: To make the Brazilian Science more competitive.

Fapesp: São Paulo Research Foundation
•Mission: to support research in all fields
•With 1% of all state revenues
–Started in 1962
•All proposals are peer reviewed (23,000 proposals in 2013)
•Annual budget: US$ 500 M in 2014
1/3 for Scholarships
2/3 for Research Grants

Higher Education and Research Institutes (102)
FAPESP: international agreements for joint research funding
USA: MIT, USC, UCDavis, Michigan, CIRM, MBL, North Carolina, Ohio, MFAH, Florida, Southern California, Texas- Austin, NSF,
DOE, NIH
Canada: Toronto, Western Ontario, McMaster, CALDO, McGill, Ontario, Waterloo, Victoria, York, Simon Fraser, Concordia, Ryerson
France: INSERM, INRIA, CIRAD, ENS, INRA, ParisTech
Spain: Salamanca, Girona
UK: Surrey, Southampton, Nottingham, KCL, Bangor, Imperial College, IOE, Keele, Bath, Birmingham, Cambridge, East Anglia, Edinburgh, Manchester, York
Netherlands: BE-BASIC, Rotterdam, TU/e
Switzerland: Ludwig Institute, ETH Zürich
Israel: Hebrew U. Jerusalem, Tel Aviv
Japan: JST, JSPS, Univ. of Tokyo
South Africa: Stellenbosch University
Australia: ATN, Melbourne, Sidney
Latin America: UFRO
International: CERN, IANAS, CIAM, IUPAC

Companies (27)
FAPESP: international agreements for joint research funding
USA: Agilent, Boeing, Microsoft Research UK: Imprimatur Capital, GSK France: BioEvents SAS/Biovision Brazil: Intel, Peugeot Citroën, Embraer, Vale, Braskem, Whirlpool, Natura, BG Brasil, BIOLAB, BP, Ci&T and Digital Assets, SABESP, DEDINI, ETH Bioenergia, Fundação Grupo Boticário, GlaxoSmithKline Brasil, Fleury Institute, Ouro Fino Saúde Animal, Oxiteno, Padtec, Telefonica Group

FAPESP international collaboration: bringing foreign scientists to SP
•Post doctoral fellowships
–Stipend, travel, some research money
•Young Investigator Awards (1.5 awards per week)
–Stipend, travel, research money
•Visiting scientists
–205 in 2010 (travel, stipend;2 weeks to 12 months)
•São Paulo Schools of Advanced Science (SPSAS)
–Each one with 50-100 young Dr students from abroad
•São Paulo Excellence Chairs (SPEC)
–For top notch scientists from abroad: full research grant for staying 3 mo. per year in SP for 3-5 years
© C.H. Brito Cruz e Fapesp

FAPESP international collaboration: sending abroad scientists from SP
•Research fellowships (2-12 mo; 158 in 2010)
•Special grants for participation in international conferences (903 awarded in 2010)
•Fellowship for short stays
–4 to 12 months doing research work abroad
–Eligible: all 12,000 FAPESP fellowship holders

Worldwide FAPESP Research Fundings

Results and challenges for state funding Research
•Results
- Sustained growth in the number of scientific papers for the last 30 years
- Strength in the education of graduate students
- D.Sc. graduated yearly: USP 2,200/Unicamp 800/Unesp 800
•Challenges
–Increase the impact of the scientific production
•Intellectual (citations) and socio-economic (health and well being)
–Increase international cooperation
–Increase the number of scientists in academia and industry
•Improve connections between academia and industry

Center for Advanced Functional Materials

AKNOWLEDGEMENT
11/13/2014

Thank you for your attention

Materials Science: evolution and perspectives.

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