Low-coherence photonic method of electrochemical processes monitoring
At a Glance
Section titled âAt a Glanceâ| Metadata | Details |
|---|---|
| Publication Date | 2021-06-15 |
| Journal | Scientific Reports |
| Authors | Monika Kosowska, PaweĆ JakĂłbczyk, MichaĆ Rycewicz, I. Alex Vitkin, MaĆgorzata Szczerska |
| Institutions | GdaĆsk University of Technology, University of Toronto |
| Citations | 6 |
| Analysis | Full AI Review Included |
Technical Documentation & Analysis: Low-Coherence Photonic Monitoring of Electrochemical Processes
Section titled âTechnical Documentation & Analysis: Low-Coherence Photonic Monitoring of Electrochemical ProcessesâReference: Kosowska et al. (2021) Scientific Reports | 11:12600.
Executive Summary
Section titled âExecutive SummaryâThis research validates a novel, hybrid opto-electrochemical platform for simultaneous, non-destructive monitoring of liquid-phase redox reactions, leveraging the unique properties of Boron-Doped Diamond (BDD).
- Hybrid System Validation: Successful integration of a fiber-optic Fabry-Perot interferometer with a standard 3-electrode electrochemical cell.
- BDD Dual Role: MPCVD BDD film acts simultaneously as the high-performance working electrode (for Cyclic Voltammetry, CV) and the reflective mirror (for optical interferometry).
- Non-Destructive Evaluation (NDE): The system operates in NDE mode, confirming the reversibility of the redox process (Fe(CN)63-/Fe(CN)64-) without damaging the sample or the BDD surface.
- High Performance: CV results show expected oxidation (0.247 V) and reduction (-0.027 V) peaks, confirming proper electrochemical functionality in the presence of the optical system.
- Miniaturization Potential: The methodology significantly reduces required sample volume and simplifies construction, paving the way for robust, low-cost lab-on-chip devices.
- Material Requirement: The success hinges entirely on the precise control and quality of the highly conductive, optically reflective BDD film, a core capability of 6CCVD.
Technical Specifications
Section titled âTechnical Specificationsâ| Parameter | Value | Unit | Context |
|---|---|---|---|
| Working Electrode Active Area | 0.2 | cm2 | BDD film on silica substrate |
| Electrolyte Concentration | 2.5 | mM | K3[Fe(CN)6] |
| Supporting Electrolyte | 0.5 | M | Na2SO4 solution |
| Cyclic Voltammetry Scan Rate | 10 | mV/s | Rate used for redox monitoring |
| Oxidation Peak Potential (A) | 0.247 | V | Anodic current peak |
| Oxidation Peak Current (A) | 0.0195 | mA | Anodic current peak |
| Reduction Peak Potential (B) | -0.027 | V | Cathodic current peak |
| Reduction Peak Current (B) | -0.0194 | mA | Cathodic current peak |
| Optical Source Wavelength | 1550 | nm | Super luminescence diode |
| Median Fringe Visibility (V) | 0.48 | a.u. | Due to liquid absorption in the cavity |
| Spectral Shift (Instability) | < 0.5 | nm | Attributed to light source instability |
Key Methodologies
Section titled âKey MethodologiesâThe hybrid system relies on the precise fabrication of the Boron-Doped Diamond (BDD) film via Microwave Plasma-Assisted Chemical Vapor Deposition (MPCVD).
BDD Film Deposition Parameters
Section titled âBDD Film Deposition Parametersâ- System: 2.45 GHz MPCVD (Seki Technotron AX5400S).
- Substrate: 1 cm x 1 cm p-type silicon (100) orientation.
- Pre-treatment: RCA cleaning followed by seeding with undoped nanodiamond slurry (4-7 nm size).
- Gas Composition: Methane (CH4), Hydrogen (H2), and Diborane (B2H6) precursors.
- Dopant Ratio: [B]/[C] ratio maintained at 10,000 ppm.
- Process Conditions:
- Microwave Power: 1300 W.
- Reactor Pressure: 50 Torr.
- Gas Flow Rate: 300 sccm.
- Growth Temperature: 700 °C (Graphite stage).
- Deposition Time: 12 h.
- Post-treatment: Hydrogenation (1100 W, 50 Torr, 15 min) after cleaning in H2SO4/KNO3 solution.
Hybrid Measurement Setup
Section titled âHybrid Measurement Setupâ- Electrochemical Cell: Standard 3-electrode configuration.
- Working Electrode: BDD film (dual role).
- Reference Electrode: Silver wire coated with silver chloride (Ag/AgCl).
- Counter Electrode: Platinum (Pt) wire.
- Optical Interferometer: Fabry-Perot fiber-optic interferometer operating in reflective mode.
- Cavity Boundaries: Fiber end-face/liquid interface and liquid/BDD film interface.
- Detection: Optical Spectrum Analyzer (OSA) used to record spectral changes resulting from refractive index perturbations.
6CCVD Solutions & Capabilities
Section titled â6CCVD Solutions & CapabilitiesâThe success of this hybrid opto-electrochemical monitoring system is predicated on the availability of high-quality, highly conductive, and optically smooth Boron-Doped Diamond (BDD) films. 6CCVD is uniquely positioned to supply and customize the critical diamond components required for replicating or advancing this research.
Applicable Materials
Section titled âApplicable MaterialsâTo replicate the dual-role functionality (electrode and mirror) demonstrated in this paper, researchers require Heavy Boron-Doped Polycrystalline Diamond (PCD) or Boron-Doped Single Crystal Diamond (SCD).
| 6CCVD Material Recommendation | Key Feature Match | Customization Focus |
|---|---|---|
| Heavy Boron-Doped PCD | High conductivity, excellent electrochemical stability, and wide potential window. | Custom thickness (0.1 ”m to 500 ”m) and large area (up to 125 mm diameter) for scale-up. |
| Optical Grade BDD | Optimized for reflectivity and low absorption loss in the 1550 nm range, crucial for interferometry. | Achievable low surface roughness (Ra < 5 nm for inch-size PCD) for superior optical performance. |
| Silicon Substrates | 6CCVD can supply BDD films deposited directly onto p-type silicon substrates, matching the experimental setup. | Custom substrate dimensions and orientations available upon request. |
Customization Potential
Section titled âCustomization PotentialâThe research utilized a BDD electrode with a specific active area (0.2 cm2) and required precise placement of the counter and reference electrodes. 6CCVD offers comprehensive customization services to meet these exacting requirements:
- Custom Dimensions and Shaping: We provide plates and wafers up to 125 mm in diameter. We offer precision laser cutting and shaping services to achieve the exact 0.2 cm2 active area or custom geometries required for miniaturized lab-on-chip integration.
- Metalization Services: While the paper used Ag/AgCl and Pt wires, future iterations may require integrated contacts. 6CCVD offers in-house metalization capabilities, including Au, Pt, Pd, Ti, W, and Cu, for creating robust electrical contacts on the BDD working electrode.
- Surface Engineering: We offer ultra-smooth polishing (Ra < 5 nm for PCD) essential for maximizing the fringe visibility and signal quality in the Fabry-Perot interferometer setup.
Engineering Support
Section titled âEngineering SupportâThe successful integration of optical and electrochemical modalities requires deep expertise in diamond material science, particularly concerning dopant concentration and surface quality.
6CCVDâs in-house PhD engineering team specializes in tailoring MPCVD growth recipes (including precise control of the [B]/[C] ratio up to 10,000 ppm and beyond) to optimize BDD films for specific hybrid sensor applications. We can assist researchers in selecting the optimal BDD grade, thickness, and surface finish necessary to extend this research into:
- Environmental Monitoring: Developing highly sensitive NDE systems for detecting heavy metals or dangerous chemical compounds.
- Biomedical Research: Creating miniaturized biosensors for glucose, DNA, or neurotransmitter detection, leveraging the BDDâs biocompatibility.
- Process Control: Implementing real-time, non-invasive monitoring of industrial electrochemical processes.
For custom specifications or material consultation, visit 6ccvd.com or contact our engineering team directly.