# Modeling Nanoparticle Synthesis via Laser Ablation for Advanced Applications

Tatiana Itina

► To cite this version:

Tatiana Itina. Modeling Nanoparticle Synthesis via Laser Ablation for Advanced Applications. 2025 EMRS Spring Meeting, Symposium O: Laser-matter interaction for life and society: fundamental mechanisms and emerging applications, Invited talk, EMRS, May 2025, STRASBOURG (FRANCE), France. ujm-05118046

HAL Id: ujm-05118046

https://ujm.hal.science/ujm-05118046v1

Submitted on 18 Jun 2025

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Laboratoire
Hubert Curien

UMR • CNRS • 5516 • Saint-Étienne

E-MRS 2025

cnrs

# Modeling Nanoparticle Synthesis via Laser Ablation
for Advanced Applications

Tatiana E. ITINA

Lab. Hubert Curien, UMR CNRS 5516, UJM, Campus Manufacture, 42000 St-Etienne, France

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Understanding mono-and bi-metallic Au and Ni
nanoparticle responses to fast heating

tatiana.Itina@univ-st-etienne.fr
Applications of NPs

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http://www.nanowerk.com/spotlight/spotid=19451.php

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Hayashi et al.

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DOI: 10.1039/C1CP22048A

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**Textiles:** anti-bacterial properties, order elimination, self-cleaning, UV protection, fireproof, release of active agents, luminescence, durability, heat, antistatic, ...(Ag, ZnO, TiO2, SiO2, CNT, etc.)

**Health:** tumor treatments, imaging, sensors, SPR, etc. (colloidal/gas Au, Ag, Si, etc.)

**Chemistry, catalysis, cosmetics:** (colloidal metal NPs, TiO2, nanoaloys, ex: AgPd, etc..., etc.)

**Food:** flavor modifications, water treatment (Ag, nanocomposites: Cu, Ni, No) can be dangerous

**Energy** (solar cells), **transport** (cooling, nanofluidics, anti-wetting, nanocomposites, etc.)

**Airspace industry, buildings, furniture**, etc.
# Advantages of NP Synthesis by Laser Ablation

## Chemical Methods

### 1. Green methods

Physical Methods

Biological Methods

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### 2. Better control over properties

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### 3. Scaling-up possibility

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Laser Ablation and NP Formation

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http://appliedspectra.com/

- Ablation threshold fluence

- Target material is heated and ejected

- Nanoparticles (NPs): in vacuum, in a background gas or a liquid (colloidal nanoparticles)

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D. Amans et al. ILM, Lyon

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Doi: 10.1007/978-3-030-63647-0_30

Experimental evidences of nanoparticle formation by LA

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Heiroth et al. JAP 2009

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Deposited nanoparticles,
courtesy of Garrelie et al.

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Colloidal nanoparticles
Barcikowski et al. APL 2007

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TEM images
Kabashin et al.

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Z. Swaitkowska

et al
# Main Questions Concerning Laser-based NP Formation

- What are the mechanisms of their formation?

- What roles do laser parameters play?

- What if we change target material?

- The role of ambient environment?

- Are there any control possibilities?

- Can more complicated nano-hybrids or nano-composites be directly fabricated by laser?

- For what specific applications these particles are most promising?

- How to predict/optimize the required nanoparticle's shape and morphology?

- If we can predict, how to fabricate them?
# Ultra-short Laser Interactions

<figure><img src="image_27.png" /></figure>

## 1. Thermal (TTM) models

$$C_e \frac{\partial T_e}{\partial t} = \frac{\partial}{\partial z} \left( k_e \frac{\partial T_e}{\partial z} \right) - \gamma (T_e - T_i) + Q_{abs}$$

$$C_i \frac{\partial T_i}{\partial t} = \frac{\partial}{\partial z} \left( k_i \frac{\partial T_i}{\partial z} \right) + \gamma (T_e - T_i)$$

⇒ Melting without ablation

⇒ Many assumptions

⇒ No motion

⇒ Hard to describe phase changes

⇒ Have to know many coefficients

## 2. Molecular dynamics approach (MD or TTM-MD)

⇒ melting, ablation

⇒ interaction potential is often assumed to be constant

## 3. Hydrodynamics (1T, 2T, one fluid, two fluids, etc.)

⇒ Need all transport coefficients

⇒ Need equation of state (EOS)

⇒ Need additional sub-models for ionisation
# TTM-MD for Femtosecond Laser Ablation

<figure><img src="image_28.png" /></figure>

## Two-temperature model (TTM)

$$C_e(T_e) \frac{\partial T_e}{\partial t} = \nabla [K_e(T_e) \nabla T_e] - G(T_e - T_l) + S(z, t),$$

$$C_l(T_l) \frac{\partial T_l}{\partial t} = \nabla [K_l(T_l) \nabla T_l] + G(T_e - T_l),$$

Kaganov et al. Sov. Phys. JETP 4, 173 (1957)

## TTM-MD model

<figure><img src="image_29.png" /></figure>

$$C_e(T_e) \frac{\partial T_e}{\partial t} = \frac{\partial}{\partial z} \left( K_e(T_e) \frac{\partial}{\partial z} T_e \right) - G(T_e - T_l) + S(z, t), \quad \text{TTM}$$

$$m_i \frac{d^2 \mathbf{r}_i}{dt^2} = \mathbf{F}_i + \xi m_i \mathbf{v}_i^T, \quad \text{MD}$$

$$\xi = \frac{1}{n} \sum_{k=1}^{n} G V_N (T_e^k - T_l) / \sum_i m_i (\mathbf{v}_i^T)^2$$
CFD or MD?

$$ \frac{\partial(1/\rho)}{\partial t} - \frac{\partial u}{\partial m} = 0 $$

$$ \frac{\partial u}{\partial t} + \frac{\partial(P_{\text{ion}} + P_{\text{el}})}{\partial m} = 0 $$

$$ \frac{\partial e_{\text{ion}}}{\partial t} + P_{\text{ion}} \frac{\partial u}{\partial m} = \gamma_{\text{ei}}(T_{\text{el}} - T_{\text{io}})/\rho $$

$$ \frac{\partial e_{\text{el}}}{\partial t} + P_{\text{el}} \frac{\partial u}{\partial m} = \frac{\partial}{\partial m} \left( \rho \kappa_{\text{el}} \frac{\partial T_{\text{el}}}{\partial m} \right) - \gamma_{\text{ei}}(T_{\text{el}} - T_{\text{ion}})/\rho + Q_{\text{L}}/\rho $$

EOS

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$$ m_i \frac{d^2 \mathbf{r}_i}{dt^2} = \mathbf{F}_i + \xi_i m_i \mathbf{v}_i^T + \mathbf{F}_i^{\text{el}} $$

LAMMPS

$$ \frac{\partial(\rho e_{\text{el}})}{\partial t} + \frac{\partial(\rho e_{\text{el}} u)}{\partial z} + P_{\text{el}} \frac{\partial u}{\partial z} = \frac{\partial}{\partial z} \left( \kappa_{\text{el}} \frac{\partial T_{\text{el}}}{\partial z} \right) - \gamma_{\text{ei}}(T_{\text{el}} - T_{\text{ion}}) + Q_{\text{L}}(t, z) $$

Embedded atom “EAM”

$$ E_i = F_\alpha \left( \sum_{j \neq i} \rho_\beta(r_{ij}) \right) + \frac{1}{2} \sum_{j \neq i} \phi_{\alpha\beta}(r_{ij}) $$

Zhakhovskii et al. Appl. Surf. Sci. 255 (2009)
# Thermodynamic Analysis of Laser Ablation

## 1-Phase explosion

3-Nucleation and
condensation

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$$ \tau_L = 100 \text{ fs}, \lambda = 800 \text{ nm}, F = 5.0 \text{ J/cm}^2 $$

## 2- Fragmentation

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M.E. Povarnitsyn, T. E. Itina et al. Phys. Rev. B, 75, 235414 (2007)

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T.E. Itina, Chem. Phys. Lett. (2008)

Explosive boiling and fragmentation
of metastable liquid
lead to the ejection of clusters and chunks
# Molecular Dynamics Simulations

Allow to get nanoparticle size distributions and describe non-equilibrium processes

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t=1 ns

$\tau = 15$ ps, $F \sim 2$ Fth, $40 \times 10$ nm, $t = 1$ ns

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L.V. Zhigilei et al.
(Virginia State University, USA)

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A. Kabashin et al.
LP3, Marseille, France

Practically all the molten material is ablated

$\text{Lab1} \sim \text{Lo In}(\text{Fabs/F}_0)$, $E>\text{Eb}$

See: M.E. Povarnitsyn, T. E. Itina et al., PRB 2007
# Laser Ablation in Liquids

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- confinement, different ablation threshold and yield

- shock wave formation

- bubble formation and oscillations

- “primary” nanoparticles are ejected

- “Secondary” particles are formed later by coagulation, coalescence/aggregation (sintering)

- fragmentation and stabilisation

## Confinement by liquid, oscillating bubbles

$$R_n(t) = \left\{ R_{na}^3 + \frac{R_{nb}^3 - R_{na}^3}{2\tau} \left[ t - \frac{\tau}{\pi} \sin\left(\frac{\pi}{\tau} t\right) \right] \right\}^{1/3}$$

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See: A. Vogel et al., J. Acoust. Soc. Am. 100(1), 1996

## Modeling approaches:
**Hydrodynamic modeling (CFD)**
**Molecular Dynamics (MD)**

- 2T semi-empirical equations of state (for metal, gold here)

- EOS for water
Single fs Laser Pulse in Liquids: TTM-HD

<caption>Density maps</caption>

3×10¹³ W/cm²

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4×10¹³ W/cm²

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5×10¹³ W/cm²

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Near ablation threshold, ejected droplets
stick together under the pressure

Povarnitsyn, Itina et al. PCCP 9 (2013)
Laser Interactions with Nanoparticles

Molecular Dynamics (MD) simulations are particularly interesting for phase transitions
and decomposition of the ablated material upon the absorption of laser radiation,
but also can be used for heating, melting, fragmentation or sintering of NPs

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t = 300 ps after the
beginning of the laser pulse

τ = 15 ps

e=0.6 eV per molecule
# NP's Fragmentation: Experiments and MD Simulations

MD results for NPs of different materials, absorbed energy, and sizes

<figure><img src="image_47.png" /><figcaption>Femtosecond laser irradiation of gold nanoparticles</figcaption></figure>

<figure><img src="image_48.png" /><figcaption>In situ observation of gold nanoparticle fragmentation under femtosecond laser irradiation</figcaption></figure>

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# Laser Interaction with Organic NPs: Eearly MD Simulations

<figure><img src="image_54.png" /><figcaption>R=50 Å, absorbed energy e=0.6 eV/mol.</figcaption></figure>

Smaller NPs

**Evaporation**

(can be also due to
Coulomb Explosion for
small clusters and fs
laser)

<figure><img src="image_55.png" /><figcaption>R=150 Å, absorbed energy e=0.6 eV/mol.</figcaption></figure>

Larger NPs

**Fragmentation due to**
**thermo-mechanical**
**effects**
# Fragmentation When There Are Many Laser Pulses

AuCo, NP R = 40 u.c.

Multi-pulse effects: simulations re-start
additional fragmentation

2d pulse

Upon
additional
fragmentation,
re-organization
and
cooling

Reducing the size of
absorbing fragments
until they do not absorb
# MD Simulations for Au, Au-Ni and AuNi

<figure><img src="image_56.png" /><figcaption>Fragmentation of a single Au NP</figcaption></figure>

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Tmax> Tc

<figure><img src="image_58.png" /><figcaption>Janus NP upon pulsed laser irradiation</figcaption></figure>

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# Laser Interaction with Metallic NPs

Vibrations and
fluid instabilities

Tmax> Tc

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Au nanocluster with N=30845 atoms and
maximum temperature T<sub>max</sub> =8000K
obtained at time delays t=0.1, 5, 10, 20,
50, 100 ps after the beginning of strong
and short (20ps) heating

Pressure vs Temperature

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T. E. Itina, RCS Nanoscale Advances 6,
5451 (2024)

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H. E. Sauceda et
al. J. Phys. Chem.
C, 116 (47), 2012
Fs Laser Interactions with Metallic NPs in Liquids

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•Heating Au to T_m, ε₀ = 0.3 eV/atom;

•complete melting of Au at T_m, ε = 1.43, ε₀ = 0.43 eV/atom;

•heating Au to the boiling temperature of T_b = 3131 K, ε = 3.5, ε₀ = 1.05 eV/atom;

•completely vaporizing Au at T_b, ε = 14.9, ε₀ = 4.48 eV/atom.
In Liquids: Bubbles and Nanoparticles

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S. Reich et al. Journal of Colloid and Interface Science
Volume 489, 1 March 2017, Pages 106-113

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M.-R. Kalus et al. Applied Surface Science
Volume 465, 28 January 2019, Pages 1096-1102

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M. K. Bhuyan et al. Scientific Reports 8,
9665 (2018)
# In Liquids: Bubbles And Nanoparticles

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M. Alheshibri et al.

<figure><img src="image_70.png" /><figcaption>## Interaction between bulk nanobubbles and positively charged nanoparticles</figcaption></figure>

Current Opinion in Colloid & Interface Science
Volume 55, October 2021, 101470

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OpenFOAM
CFD
Simulations

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Force balance
model

Interaction between a Collapsing Bubble and a Movable Particle,
X. Zheng et al. Water 2020, 12(12), 3331
Materials that respond to a stimulus or their environment to produce a
dynamic and reversible change

<figure><img src="image_73.png" /></figure>

<figure><img src="image_74.png" /><figcaption>A</figcaption></figure>

<figure><img src="image_75.png" /><figcaption>B</figcaption></figure>

<figure><img src="image_76.png" /><figcaption>C</figcaption></figure>

<figure><img src="image_77.png" /><figcaption>D</figcaption></figure>

<figure><img src="image_78.png" /></figure>

V. Coviello et al.
*ChemPhysChem* **2022**
V. Amendola et al., Italy

Laser give many possibilities: sintering,
alloying, fragmentation, etc.
# Predictions of NP's Properties for Applications

<table><thead><tr><td>Configuration</td><td>Plasmonic Properties</td><td>Magnetic Properties</td><td>Optimal Size Range</td><td>Applications</td></tr></thead><tbody><tr><td>Core-Shell Au-Ni</td><td>Strong plasmonic resonance at 520 nm (visible)</td><td>Moderate magnetic properties from Ni shell</td><td>20 nm Au core + 10 nm Ni shell</td><td>Photothermal therapy, magnetic targeting, drug delivery</td></tr><tr><td>Core-Shell Ag-Fe</td><td>Strong plasmonic resonance at 400-450 nm (visible)</td><td>Strong magnetic properties from Fe shell</td><td>20 nm Ag core + 10 nm Fe shell</td><td>Sensing, hyperthermia, MRI contrast agents</td></tr><tr><td>Au-Ni Nanorods</td><td>Tunable plasmonic resonance in NIR range</td><td>Moderate magnetic properties from Ni shell</td><td>30-40 nm length, 10-20 nm diameter</td><td>Optical sensing, NIR therapy, magnetic applications</td></tr></tbody></table>

<figure><img src="image_79.png" /></figure>

<figure><img src="image_80.png" /><figcaption>Mie Theory Absorption and Magnetic Momentum for Ni-Au Core-Shell Nanoparticles</figcaption></figure>

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Fabrication Methods: Fs Laser Co-Ablation

<figure><img src="image_85.png" /><figcaption>Experiments:
Z. Switkowska, O. Polit, et al.
PAN Krakow, Poland
A. Pastukhov,
A. Kabashin et al.
LP3, Marseille, France
(PHC POLONIUM PROJECT)</figcaption></figure>

1030 nm

•Fluence: 10 J/cm2

•Frequency: 10 kHz

•Pulse duration: 450 fs

•Target placed 10 mm under liquid surface

•Volume of liquid: 6 ml

•Irradiation time: 30 min -3h

•„Au_in_Ni” stands for gold ablated in the presence of Ni NPs

•„Ni_in_Au” is for reversed configuration: nickel ablated in presence of Au NPs

<figure><img src="image_86.png" /></figure>
# Molecular Dynamics Simulations (MD) vs Experiments

Au NP on Ni NP

<figure><img src="image_87.png" /></figure>

Au Ni

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Maximum temperature, K

Upon 1st heating and quenching

Upon 2st heating of 20 ps and cooling

Tmax, K

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1200

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2200

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4200

T. E. Itina, Nanoscale Adv., 2024, 6, 5451 DOI: 10.1039/D4NA00634H
# Excess Gibbs Energy and Phase Diagrammes

<figure><img src="image_93.png" /><figcaption>## Au and Ni Pulsed heating of Ni and Au NP, maximum T= 5500 K</figcaption></figure>

<figure><img src="image_94.png" /><figcaption>## Au and Pt T=const=1100K</figcaption></figure>

<figure><img src="image_95.png" /></figure>

<figure><img src="image_96.png" /></figure>

A. Taranovskyy et al. Phys. Chem. Chem. Phys., 2021,23, 6116-6127

The results mostly rely on change in Gibbs energy, which depends on

-Temperature

-Composition

-Sizes
# Thermal Stability of Alloy, Janus or Core-Shell NPs

<figure><img src="image_97.png" /></figure>

V. Coveillo et al. Advanced Science, 2025
DOI 10.1002/advs.202416035

ARQUS project with:
Group Prof. V. Amendola,
Padova University, Italy

## Au and Fe NP

<figure><img src="image_98.png" /></figure>

$$ \text{Gibbs free energy for Alloy NPs (Gss)} \\ G_{ss} = X_{Au}G_{Au} + X_{Fe}G_{Fe} + \Delta G_{mix} + (2Y_{ss}V_{AuFe})/(D/2) $$

$$ \text{Gibbs free energy for CS NPs (Gcs)} \\ G_{cs} = X_{Au}G_{Au} + X_{Fe}G_{Fe} + \alpha_{Au}S_{Au}Y_{Au} + \alpha_{Fe}S_{Fe}Y_{Fe} + G_{int} $$
# AuPt alloy NPs: Role of Size and Composition

Long heating at constant temperature of AuPt alloy NPs, Tmax =1100 K

<table><thead><tr><th>R=12, f=0.5</th><th>R=25, f=0.2</th><th>R=25, f=0.5</th><th>R=25, f=0.8</th></tr></thead><tbody><tr><td></td><td></td><td></td><td></td></tr><tr><td></td><td></td><td></td><td></td></tr><tr><td></td><td></td><td></td><td></td></tr></tbody></table>

AuPt alloy NPs upon long heating at 1100 K – partial segregation is observed depending on size, but also on composition (it is more probable at f=0.5 for all the sizes)
# Wang-Landau Monte Carlo for Probing Thermodynamic Stable Configurations vs DFT based Machine Learning

<figure><img src="image_99.png" /></figure>

## Machine Learning

Number of configurations of alloy NP models consisting of 201, 405, 711, and 1289 atoms

Y. Nanba Journal of Computer Chemistry, Vol. 9, 2022-0013 (2023)
# The Role of Chemistry in the Experiments with Ultra-Short Laser Pulses (Au-Ni NPs in Acetone)

<figure><img src="image_100.png" /></figure>

*Plasmonic properties of Au-Ni nanoparticles, LP3, Marseille*

<figure><img src="image_101.png" /></figure>

T. Itina et al, Lase 2025, SPIE

Carbon was
found
on the
surface
of Ni NP

Ni NP
oxidation
was found

Ni and Au NPs were produced via femtosecond laser ablation in acetone
(150 µJ, 490 fs, 10 kHz repetition rate).
HR-TEM images of Ni NPs and size distribution of Ni-Au NPs after 3 hours of co-fragmentation
# ReaxFF MD : Ni NP in O₂ and C

Ni nanoparticle in a mixture of oxygen (blue) and carbon (yellow) at the beginning of the simulation (a) and upon heating to 1800 K during 12.5 ps (b). One can clearly see chemical reactions in the system and particularly at the surface.

<figure><img src="image_102.png" /><figcaption>Ti in O₂ after fs laser treatment</figcaption></figure>

<figure><img src="image_103.png" /></figure>

I.S. Omeje et al. 2025, *Surfaces and interfaces*

For more details concerning
oxidation of Ni NP see:
poster by A. TOULIL et al EMRS-2025

Typical film thickness formed on metal surface inversely correlates to the change
in the number of molecules at different maximum temperatures.
ReaxFF Molecular Dynamics and DFT Simulations

<figure><img src="image_104.png" /></figure>

<figure><img src="image_105.png" /></figure>

<figure><img src="image_106.png" /></figure>

<figure><img src="image_107.png" /></figure>

<figure><img src="image_108.png" /><figcaption>Cu-ethanol and CuO-ethanol</figcaption></figure>

<figure><img src="image_109.png" /></figure>

<figure><img src="image_110.png" /></figure>

<figure><img src="image_111.png" /></figure>

<figure><img src="image_112.png" /></figure>

<figure><img src="image_113.png" /></figure>
# Complex Nano-Objects Formation by Laser Co-Ablation

<figure><img src="image_114.png" /></figure>

STEM image of
nanostructures

obtained by mixing of negatively charged laser-ablated
Au NPs and positively charged laser-ablated Fe oxide
NPs. Right: Calculated extinction spectra of bare Au NPs
(red line), Fe oxide NPs (black line) and core-satellite Au-
Fe NPs (green line).

<figure><img src="image_115.png" /></figure>

<figure><img src="image_116.png" /></figure>

<figure><img src="image_117.png" /></figure>

Raspberry-like, core-shells or alloys

<figure><img src="image_118.png" /></figure>
# Symmetry Breaking

<figure><img src="image_119.png" /><figcaption>## Au NP in water</figcaption></figure>

<figure><img src="image_120.png" /></figure>

Itina T.E, Nanoscale Adv 2024, 6, 5451

Bhuyan, M. K., Soleilhac, A., Somayaji, M., Itina, T. E., Antoine, R., & Stoian, R. (2018). Scientific Reports, 8(1), 9665.

<figure><img src="image_121.png" /><figcaption>## Si NP</figcaption></figure>

Rudenko, A., Ladutenko, K., Makarov, S., & Itina, T. E. (2018). Nanoparticle. Advanced Optical Materials, 6(7), 1701153.

<figure><img src="image_122.png" /><figcaption>## Fluid instabilities</figcaption></figure>

<figure><img src="image_123.png" /><figcaption>## Ion Jets and Rayleigh break-up</figcaption></figure>

Journal of Fluid Mechanics, Volume 884, 10 February 2020, A31
SUMMARY

The results highlight the diverse strongly non-equilibrium phenomena induced by
ultrashort pulses, from material ablation to modifications of nanoparticles.

* Nanoparticles can be directly ejected from targets by laser pulses

• Nanoparticles can be either sintered or fragmentated

* Laser pulses do induce nanoparticle vibrations prior to fragmentation

* Change in Gibbs energy is important (size, concentration, T, fraction of elements)

• In liquids, bubbles may affect nanoparticles and vise versa

* Better understanding and control over chemical reactions can be achieved by using ReaxFF MD and DFT.

These findings pave the way for the development of multifunctional nanoparticles
with potential applications in catalysis, magneto-optical devices, and biomedicine.

tatiana.Itina@univ-st-etienne.fr
ACKNOWLEDGEMENTS

We acknowledge the financial support of Univerité Jeann Monnet and CNRS, as well as CINES of France for the computational resources needed for large-scale simulations.

Thank you very much
for your attention!

tatiana.Itina@univ-st-etienne.fr