Dorota A. Pawlak N

Testo completo

(1)

Institute of Electronic Materials Technology

www.itme.edu.pl

Є Є Є Є Є Є Є Є Є Є M Є Є B L

N S S Є Є Є Є Є Є M Є Є Є Є Є Є B L

Dorota A. Pawlak N

Dorota A. Pawlak Dorota A. Pawlak

Self-organized eutectic micro- and nanostructures and other bottom-up approaches

towards applications

Self Self - - organized eutectic organized eutectic micro micro - - and nanostructures and other and nanostructures and other

bottom

bottom - - up approaches up approaches towards applications towards applications

Dorota.Pawlak

@itme.edu.pl

(2)

New concepts & new materials in PHOTONICS

PHOTONIC

CRYSTALS METAMATERIALS

PLASMONIC

MATERIALS

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Bottom-up materials Photonics/photovoltaics

Metamaterials

Photonic materials

Our research

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Our bottom-up approaches

based on directional solidification

EUTECTIC

solidification NANOPARTICLES

dispersion

(5)

Eutectic point

Solid phase A

Solid phase + AB

liquid

A B

Binary eutectic phase diagram

(6)

Tb

3

Sc

2

Al

3

O

12

/TbScO

3

TbScO

3

Tb

3

Sc

2

Al

3

O

12

Chem. Mat. (2006), 18, 2450,

D. A. Pawlak, K. Kolodziejak, S. Turczynski, et al.

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•••• Almost arbitrary COMPONENT materials

Versatility of EUTECTICS

•••• Many special GEOMETRICAL MOTIFS

•••• MONOLITH and MULTIPHASE MATERIAL

•••• Controlled structuring size

from micro to nano regime

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•••• MONOLITH and MULTIPHASE MATERIAL

BULK 3D material - Monolith Micro/nano structured

3 mm diam.

SrTiO3-TiO2

5mm

Bar 1 µ m

Bar 100 µ m

(9)

•••• Almost arbitrary COMPONENT materials

METALS SEMICONDUCTORS ISOLATORS

OXIDES FLUORIDES

(Anti) FERROELECTRICS (Anti) FERROMAGNETICS

NONLINEAR OPTICALLY ACTIVE

etc.

ORGANIC COMPOUNDS

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1 µm 3 µm 1 µm

20 µm 1 µm

3 µm 1 µm

10 µm

10 µm

AA BB CC

DD EE FF

GG HH II

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0.15 mm/min

0.3 mm/min

0.45 mm/min

1 mm/min

Hig her

pu llin

g ra te –

sm alle r p

atte rn

3 µm

3 µm

3 µm

3 µm

•••• Controlled size of structuring

from micro to nano regime

(12)

heating system

shaper

seed Ir afterheater

melt

Ir crucible

Micro-pulling down method

Fukuda, T. et al. J. Cryst. Growth 1994, 142, 339-343

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- alloys - steals (better mechanical properties) - Some inks for printers (eutectic mixtures)

- Liquid crystals eutectics – the stable liquid crystalline phase in a broader temperature range – LCD – liquid crystal display

Other

applications Eutectic for Polish winter

Water & salt

Eutectic point at:

-21 °°°° C, 29% NaCl

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Eutectic especially for people loving chocolate!

Source: Kenneth A. Jackson at the University of Arizona.

http://science.nasa.gov/newhome/headlines/msad15sep99_1.htm

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T

E

– the eutectic temperature T

0

– the growth temperature C

E

– the eutectic composition

When T 0 < T E

(under-cooling),

the reduction in the free energy of the two-phase solid in comparison with the liquid is the driving force behind the growth of both α and β phases

The driving force

T 0

T E

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COUPLED GROWTH

A solute redistribution takes place because each solid

phase rejects the other solute

component and…

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COUPLED GROWTH

…and

the concentration profile in the liquid ahead of the lamella tips is no longer

a flat surface

Extensive lateral mixing takes place as a consequence of this concentration

gradient at the α - β interface, and a diffusion flux parallel to the solid-liquid interface reduces the concentration

oscillation

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Dorota.Pawlak@itme.edu.pl

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M B N S Є Є Є Є Є Є Є Є Є Є Є Є L

M B N S

Metallodielectric materials

Metallodielectric materials

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METALLO-DIELECTRIC STRUCTURES

2. Direct growth of eutectic including metallic phase

3. Growing an eutectic with an oxide which can

be easily reduced to metal + ionic conductor phase 1. Removing one of the phases in the eutectic

and filling it with metallic phase

A. Revcolevschi, et al., Nature, 316, 335, (1985).

R. I. Merino, et al. Recent Res. Devel. Mat. Sci 4, 1, (2003).

M. A. Laguna-Bercero, et al. J. Eur. Ceram Soc. 25, 1455, (2005).

M. D Watson, et al., J. Amer. Ceram. Soc., 53, 112-113, (1970).

R. P. Nelson, J. Amer. Ceram. Soc., 53, 527, (1970).

D. A. Pawlak et al., Chem. Mat. 18, 2450, (2006).

from eutectics

D. A. Pawlak et al., Adv. Funct. Mat. (2010) .

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Tb

3

Sc

2

Al

3

O

12

/TbScO

3

Chem. Mat. (2006), 18, 2450,

D. A. Pawlak, K. Kolodziejak, S. Turczynski, et al.

10 µm

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TbScO 3

Chem. Mat. (2006), 18, 2450, D. A. Pawlak, K. Kolodziejak, S. Turczynski, et al.

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Tb

3

Sc

2

Al

3

O

12

/TbScO

3

filled in with aluminium in 1/4 of the height of the fibres

Tb

3

Sc

2

Al

3

O

12

/TbScO

3

filled in with aluminium in 1/4 of the height of the fibres

Chem. Mat. (2006), 18, 2450

1 µm

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METAMATERIALS METAMATERIALS

D. R. Smith, et al. Science 2006, 314, 977; C. M. Soukoulis et al., Science 2007, 315, 47.

D. A. Pawlak et al., Adv. Funct. Mat. 2010

Split-ring resonator-like geometry by self-organization

TiO2

SrTiO3

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D. A. Pawlak, et al.

Adv. Funct. Mat, (2010), 20, 1116.

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SrTiO

3

-TiO

2

etched and covered with silver (250 nm) HRSEM

<001>

(along the 4 fold axis of rutile)

Adv. Funct. Mat. 2010, 20, 1116, Pawlak et al.

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Geometry of an eutectic depends on:

•••• Entropy of melting of phases

•••• Volume fraction of phases

•••• Growth rate

•••• Temperature gradient

How do we get such a shape ?

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Classification of Eutectic Microstructures

(Hunt & Jackson*) based on metals

Classification of Eutectic Microstructures

(Hunt & Jackson*) based on metals

*J. D. Hunt, K. A. Jackson, Trans. Metal. Soc. AIME, 236 (1966) 843-852

• Nonfacet-nonfacet

χχχχ

αααα

<2 and χχχχ

ββββ

<2

• Facet-nonfacet

χχχχ

αααα

<2 and χχχχ

ββββ

>2

• Facet-facet

χχχχ

αααα

>2 and χχχχ

ββββ

>2

• Nonfacet-nonfacet

χχχχ

αααα

<2 and χχχχ

ββββ

<2

• Facet-nonfacet

χχχχ

αααα

<2 and χχχχ

ββββ

>2

• Facet-facet

χχχχ

αααα

>2 and χχχχ

ββββ

>2

REGULAR

Irregular or complex

Independent crystals

(based on topography of the crystallization front)

*J. D. Hunt, K. A. Jackson, Trans. Metal. Soc. AIME, 236 (1966) 843-852 e

S L

e

e

T

H H

T

S = ∆ H = −

[ ]

Kmol

Entropy J

of melting

g e

R

S

χ =

Dimensionless entropy of

melting

] [

314472 ,

8 molK

R

g

= J

where

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Atomically-ROUGH crystallization front

Liquid

Crystal

Influence of crystallization front (entropy of melting) on the geometrical motifs appearing in eutectics

Atomically-SMOOTH crystallization front

Crystal Liquid

Faceted crystals

(flat surfaces)

Non-faceted crystals

(curved surfaces)

< 2

= ∆

g e

R χ S

> 2

= ∆

g e

R

χ S

(30)

32 , 1 0

< π g

v

Fibrous

microstructure

When

phase boundary area is smaller for FIBROUS eutectic, thus the energy of the phase boundaries is smaller

Microstructure with minimal

energy of the phase boundaries αααα / ββββ

For regular eutectics: FIBROUS & LAMELLAR

Influence of volume fraction (g

v

) of phases on geometry of eutectic microstructure

Phase boundary area

Phase boundary

surface tension

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The change of entropy of the eutectic phases, ∆∆∆∆ S

r

[J/(K·mol)]

Volume fraction of phases, g

v

Fraś, Metal crystallization

Quasi-regular Lamellar

Anomalous eutectics

Fibrous

Complex regular

Irregular Broken lamellar Regular

eutectics

0.6 0.8

0.4

0.2

23

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M B N S Є Є Є Є Є Є Є Є Є Є Є Є L

M B

N S Directionally solidified materials Directionally solidified materials

Photonics

-nanoplasmonic materials with:

(i) resonances at various wavelength

(ii) various geometries of particles/precipitates

(iii) various chemical composition - solid state visible lasers

(via enhanced PL, and up-conversion)

- nonlinear absorbers

(via enhanced nonlinearities)

- filters

- subwavelength imaging

- directional emissivity control

Photovoltaics

-Enhanced performance of Silicon Solar cells

(via enhanced up-conversion of waves above 1100 nm)

Photovoltaics Catalysis

-broadband absorption due to multi-bandgaps -porous materials for catalysis

Photoelectrochemistry

-photoanodes in PECs -water purification

Dorota.Pawlak@itme.edu.pl

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Є M Є Є Є Є B L

N S S Є Є Є Є M Є Є Є Є Є Є Є Є B L

N

FORTH FORTH

Contract NMP4-SL-2008-213669

ENgineered SElf-organised Multi-component structures with novel controllaBLe

Electromagnetic functionalities

ENSEMBLE

Cooperation

NMP Theme

https:/www.ensemble-fp7.eu

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ITME EUTECTIC TEAM

w w w . i t m e t e a m . p l

Marcin Marcin Marcin Marcin

Gajc Gajc Gajc

Gajc Andrzej

Stefanski Kasia

Sadecka

Krzysiek Orlinski

Andrzej Klos

Krzysiek

Bienkowski Pawel Osewski

Sebastian Turczynski Kasia

Kolodziejak

Marta Gdula

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THANK YOU!

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