Nanocrystallinity:

* Chemical intrinsic properties (Nanokinkendall effect)

* Calculated absorption spectra of quasispherical Au, Ag and Cu 5 nm nanoparticles: DDA

simulation

* The coherent acoustic phonons (l=0)

* Quadrupolar vibrational modes (l=2)

* Segregation processes during the supracrystal growth process

* High index Au nanocrystal superlattice plane

* Supracrystals mechanical properties

* Hierarchical elastic properties of supracrystals.

decahedron icosahedron Ino decahedraMarks decahedra cubooctahedron Troncated octahedron

Amorphous defects single crystals

Nanocrystallinity: Crystalline structure of nanoparticles

Chemical and physical intrinsic properties

Chemical intrinsic properties (Nano-kinkendall effect)

.Z. Yang, N. Yang and M.P.Pileni J.Phys.Chem.C., 2015, 119, 22249- 22260 Z. Yang, N. Yang, J. Yang, J. Bergström and M.P. Pileni Adv.Funct.Mater.,2015,

25, 891-897,Z .Yang, J.Yang, J.Bergström, K.Khazen, and M. P. Pileni Phys. Chem. Chem. Phys.,2014, 16, 9791-9796 Z .Yang, M ; Walls, I. Lisiecki, and M. P.

Pileni. Chem. Mater. 2013, 25, 2372-2377 , Z.Yang, I.Lisiecki, M. Walls, M.P. Pileni ACS Nano., 2013, 7, 1342–1350 I.Lisiecki, S.Turner, S.Balls, M.P.Pileni and

G.Van Tendeloo. Chem. Mat., 2009, 21, 2335-2338, I. Lisiecki, M. Walls, D. Parker and M.P. Pileni, Langmuir, 2008, 24, 4295-4299

yolk/shell Hollow: polycrystalline shellcore/shellsolid

Size

Kirkendall effect

2.2 Å

2.2 Å

3 nm3 nm

2.4

6 Å

2.4

6 Å

P. Yang, H. Portalès, and M. P. Pileni, J.Chem.Phys., 2011, 134, 024507-1/6,

N. Goubet, I. Tempra, J. Yang, G. Soavi, D. Polli, G. Cerullo and M. P. Pileni Nanoscale, 2015,7, 3237–3246.

Discrimination of decahedral MTPs from 5nm nanoparticles with mixed crystallinities

Calculated absorption spectra of quasispherical Au, Ag and Cu 5 nm nanoparticles:

DDA simulation

Ag CuAu

Cuboctahedron Truncated octahedron Decahedron Icosahedron Sphere

* The DDA target is represented by a finite periodic cubic array of

polarizable points (dipoles)

* The Maxwell’s equations of each dipoles are resolved considering the

interaction between the dipoles

* DDA is a flexible and powerful technique to calculate the scattering and

absorption for targets with arbitrary shapes

DDA Simulation

The Localized Surface plasmon resonance determined experimentally is:

* larger for polycrystalline phase than for single domain

* Does not depend on the nanocrystal size in the range from 5 to 12nm

ExperimentsNanocrystals dispersed in hexane

No changes in the coherent acoustic phonons (l=0)

n polycrystals = 517 3 GHz

n single crystal= 506 3 GHz

D. Polli I. Lisiecki, H. Portalès, G. Cerullo and M.P. Pileni. ACS Nano., 2011, 5, 5785-5791.

N. Goubet, C.Yan, D. Polli, H.Portalès, I.Arfaoui, G. Cerullo and M. P. Pileni Nano Lett., 2013,13, 504−508.

Du = 2.2 % n polycrystals= 6008 GHz

n single crystal= 58610 GHzDu = 2.3%

Frequency calculation by using Resonant Ultra-Sound (RUS) calculations:The model uses bulk elastic constants

Physical Review B 2009, 79.

npolycrystals= 692GHz

n single crystal= 682 GHz

Du = 1.5%npolycrystals= 599 GHz

* No dependencies on the acoutic phonons frequency with nanocrystallinity

* Significant damping faster for polycrystalline Au nanoparticles and none with Co nanoparticles

n single crystal= 554 GHzDu = 1.5

YanFen Wan; Hervé Portalès; Nicolas Goubet; Alain Mermet; Marie-Paule Pileni, Nano Research., 2013, 6, 611–618.

Segregation processes during the supracrystal growth process

200 μm

5 μm

5 μm

-300 -200 -100 0 100 200 300

Raman shift (GHz)

Inte

nsity

(arb

itra

ryu

nits)

-300 -200 -100 0 100 200 300

Raman shift (GHz)

Inte

nsity

(arb

itra

ryu

nits)

Single domain nanocrystals

Polycrystalline nanocrystals

low-frequency micro-Raman spectroscopy

Single domain supracrystals of single domain nanocrystals

Supracrystals film of polycrystalline nanocrystals

Single domain

nanocrystals 5 nm-1

5 nm-1Polycrystal nanocrystals

Orientational and translational orders Translational orders

N. Goubet, J.Yang, P.A.Albouy and M.P.Pileni Nano. Lett., 2014, 14, 6632-6638.

High index Au nanocrystal superlattice plane.

5 µm 5 µm

100 nm100 nm

Mixture single domain 8nm Co and

single domain 5nm Au nanocrystals

4 5 6 7 8 9 10

0

10

20

30

40

50

60

70

80

Popula

tion

Diameter (nm)

Mixture single domain 8nm Co and

polycrystalline 5nm Au nanocrystals

100 nmAu

Co

Single domain Polycrystal

1.1 ± 0.37 GPa 0.03 ± 0.01 GPa

N. Goubet, Yan, C. Yan, D. Polli, H. Portales, I. Arfaoui, G. Cerullo, M.P. Pileni. Nano Lett , 2013, 13, 504-508.

Supracrystals mechanical properties

Before indentation After indentation

Supracrystal of single domain nanocrystals stiffer than of polycrystalline

nanoparticles having same size (5nm)

20 nm

20 nm

20 nm

Orientational and

translational orders

translational order

polycrystals

Single domains

Hierarchical elastic properties of supracrystals

2 nm2 nm

2 μm 2 μm2 μm

2 nm

hcpb

Angle (Degree)

2nd Ring

(a) (b)

3 nm-1

Inte

nsity

1s Ring

(c)ε-Co

hcp-Co

3 nm-1

Inte

nsity

Amorphous C12 C18

E (GPa) 0.08 ± 0.03 0.7 ± 0.4

dpp (nm) 3.0 3.4M. Gauvin, N. Yang, Z. Yang, I. Arfaoui, and M. P. Pileni Nanoresearch, 2015, 8, 3480-3487

Amorphous e phase hcp

E (GPa) 0.7 ± 0.4 1.7 ± 0.5 6.6 ± 1.5

dpp (nm) 3.4 3.4 3.2

hcp

e phase

Amorphous

Amorphous e phase