Carbon nanoparticles fabricated by infrared laser ablation of graphite and polycrystalline diamond targets

At a Glance

Metadata	Details
Publication Date	2016-10-17
Journal	physica status solidi (a)
Authors	Mariusz Dudek, Adam Rosowski, Anna Koperkiewicz, Jarosław Grobelny, Radosław A. Wach
Institutions	Oxford Lasers (United Kingdom), Lodz University of Technology
Citations	17
Analysis	Full AI Review Included

Technical Documentation and Analysis: MPCVD Diamond for Carbon Nanoparticle Synthesis via LP-PLA

Executive Summary

This documentation analyzes the application of Polycrystalline Diamond (PCD) targets for the synthesis of Carbon Nanoparticles (CNPs) via Liquid Phase - Pulsed Laser Ablation (LP-PLA).

Validated Synthesis Method: LP-PLA successfully generated stable CNP colloids using both graphite and high-purity MPCVD Polycrystalline Diamond (PCD) targets submersed in liquid media (water/isopropanol).
Optimal Material Selection: PCD targets are superior precursors, demonstrating a beneficial graphitization process under high laser power, critical for tailoring the resulting CNP phase structure.
Controlled Nanoparticle Size: DLS analysis confirmed the production of two distinct CNP populations (typically 60-75 nm and 140-170 nm fractions), which can be partially controlled by tuning the laser power.
High Stability Colloids: The resulting CNPs exhibited Z-potentials in the optimal range of -17 mV to -30 mV (absolute value), indicating excellent colloidal stability necessary for long-term liquid suspension and subsequent functionalization.
Targeted Applications: The resulting CNPs, characterized by robust fluorescence and favorable biocompatibility, are ideal for advanced biomedical applications such as bio-imaging, biosensors, and targeted drug delivery systems.
6CCVD Advantage: 6CCVD specializes in the high-purity, large-area MPCVD PCD targets (up to 125 mm) required for scaling this high-throughput, top-down synthesis technique.

Technical Specifications

The following hard data points summarize the key parameters and achievements of the LP-PLA process using carbon targets, extracted from the research.

Parameter	Value	Unit	Context
Laser Wavelength	1064	nm	Infrared SPI Fiber Laser System
Pulse Duration	200	ns	Fixed for LP-PLA Synthesis
Operating Frequency	25	kHz	Fixed for LP-PLA Synthesis
Laser Spot Size	35	µm	Diameter on target surface
Scan Speed	600	mm/s	Laser movement rate
Highest Tested Power	7.52	W	For PCD and Graphite ablation
PCD CNP Small Fraction Size (DLS)	60 ± 11 to 74 ± 19	nm	Produced in deionised water
PCD CNP Large Fraction Size (DLS)	142 ± 37 to 163 ± 39	nm	Produced in deionised water
Lowest Polydispersity Index (PDI)	0.202	N/A	PCD target @ 5.27 W (Indicates high size homogeneity)
Z-Potential Range (PCD)	-17.60 to -22.07	mV	Measured in deionised water (Colloidal stability indicator)
Target Ablation Area	6 x 6	mm²	Total processed area
Raman Signal Confirmation	1350 and 1580	cm^-1	D and G bands, characteristic of graphitic/amorphous carbon

Key Methodologies

The synthesis of Carbon Nanoparticles (CNPs) relies on precise control over the target material and the LP-PLA processing environment.

Target Preparation: Polycrystalline Diamond (PCD) or graphite targets were prepared and submersed in oxygen-containing solvents (deionised water or isopropanol).
Laser Setup: A 20 W SPI pulsed fiber laser (1064 nm) with M² < 1.6 beam quality was utilized, focused through a Linos F-Theta 100 mm lens.
Parameter Control: Processing parameters were tightly controlled: 200 ns pulse duration, 25 kHz frequency, and average power modulation (0.18 W up to 7.52 W).
Scanning and Ablation: A 6 mm x 6 mm area was processed using an automated scanner, repeating the scan 1250 times to achieve sufficient exposure and material removal.
Chemical Modification: Ablation in oxygenated solvents (water/isopropanol) facilitates the creation of CNPs functionalized with OH groups, promoting stability and biocompatibility.
Characterization Suite: Resulting CNPs were analyzed rigorously using Dynamic Light Scattering (DLS) for size and stability (Z-potential), UV-Vis, and Raman Spectroscopy (532 nm laser) to determine phase structure and purity.
Morphological Analysis: Atomic Force Microscopy (AFM) and Scanning Transmission Electron Microscopy (STEM) were used to confirm particle size and morphology, corroborating DLS results.

6CCVD Solutions & Capabilities

This research demonstrates a powerful, scalable technique for generating high-value carbon nanomaterials, positioning 6CCVD’s premium MPCVD diamond targets as the ideal starting material for replication and scale-up.

Applicable Materials

To replicate and extend this research for industrial or advanced laboratory applications, 6CCVD recommends:

High Purity MPCVD Polycrystalline Diamond (PCD):
- Requirement Fit: The paper successfully used PCD targets to generate CNPs with controlled phase structure and specific optical properties. Our MPCVD PCD offers high purity and consistent structural integrity necessary for reproducible ablation yields and properties.
- Ablation Consistency: High quality PCD minimizes impurities that could leach into the solvent, ensuring clean, high-stability colloids suitable for sensitive biomedical applications.
- Custom Dimensions: Available in plates/wafers up to 125 mm diameter, significantly exceeding typical lab target sizes, enabling high-throughput LP-PLA synthesis.
Single Crystal Diamond (SCD) Targets (For R&D Extension):
- While the paper focused on PCD, utilizing optical grade SCD targets (0.1µm - 500µm thickness) could allow researchers to investigate how crystallographic orientation and lower grain boundaries influence particle size homogeneity, phase structure conversion, and fluorescence efficiency during LP-PLA.

Customization Potential

LP-PLA efficiency is critically dependent on the target material’s surface preparation and dimensions. 6CCVD provides customization capabilities that directly support optimization and scaling of this synthesis method:

Research Requirement	6CCVD Capability	Direct Benefit to Client
Target Dimensions	Custom plates and wafers up to 125 mm in diameter, and substrates up to 10 mm thickness.	Allows for industrial scale-up and high-volume CNP production from a single target.
Surface Finish	PCD Polishing to achieve Ra < 5 nm (for inch-size wafers).	Ensures highly consistent laser energy coupling and reproducible ablation behavior, minimizing initial surface scattering effects.
Functionalization	Custom Boron-Doped Diamond (BDD) target fabrication.	Enables the production of specialized CNPs (BDD Nanoparticles) with tailored electrochemical properties for advanced biosensor or energy storage applications, extending the scope of the original research.
Integrated Structures	Internal Metalization Capabilities (Au, Pt, Pd, Ti, W, Cu).	While not explicitly used for ablation, metal layers can be applied post-ablation for integrated sensor platforms or contacted electrodes utilizing the fabricated CNPs.

Engineering Support

6CCVD provides comprehensive technical support driven by our in-house PhD material science team:

Material Selection for CNP Synthesis: We offer consultation on selecting the optimal diamond material (PCD vs. SCD, thickness, and doping level) to match required CNP specifications (size, PDI, and quantum yield).
LP-PLA Optimization: Our experts can assist in correlating specific MPCVD target properties (e.g., surface roughness, grain size) with achieved CNP characteristics, aiding researchers in optimizing their laser parameters for specific Biomedical Imaging or Biosensor projects.
Global Logistics: We guarantee prompt global shipping (DDU default, DDP available) to ensure rapid supply chain integration for time-sensitive research and development projects worldwide.

For custom specifications or material consultation, visit 6ccvd.com or contact our engineering team directly.

View Original Abstract

This paper presents the results of carbon nanoparticles (CNPs) production by infrared laser ablation of a graphite or a polycrystalline diamond target, submerged in one of two solvents, water or isopropanol. The targets were irradiated using a SPI fibre laser with a wavelength of 1064nm being operated at different average powers. After laser-assisted synthesis of CNPs, the resulting colloids, i.e particles in a liquid medium, were examined using the analytical techniques of dynamic light scattering, UV-Vis, Raman spectroscopy and fluorescence spectroscopy. The results show that the properties of CNPs strongly depend on processing conditions of the liquid phase-pulsed laser ablation (LP-PLA) process. In particular, the size of nanoparticles produced are affected by the processing parameters of the laser ablation. The results show that the laser processing of a graphite target in deionised water and in isopropanol produces carbon nanoparticles with properties that are beneficial for various biochemical and biomedical applications. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim

Tech Support

Original Source

DOI: https://doi.org/10.1002/pssa.201600318