A 3D Printed Air-Tight Cell Adaptable for Far-Infrared Reflectance, Optical Photothermal Infrared Spectroscopy, and Raman Spectroscopy Measurements

At a Glance

Metadata	Details
Publication Date	2024-12-16
Journal	Instruments
Authors	A. Paolone, Arcangelo Celeste, Maria Di Pea, Sergio Brutti, Ferenc Borondics
Institutions	National Interuniversity Consortium of Materials Science and Technology, Synchrotron soleil
Citations	1
Analysis	Full AI Review Included

Technical Documentation & Analysis: MPCVD Diamond for Advanced Spectroscopic Cells

Executive Summary

This research successfully demonstrates a 3D-printed, air-tight cell designed for the in situ spectroscopic analysis of air- and moisture-sensitive materials, particularly those relevant to battery technology ($\text{Li}_2\text{CO}_3$, $\text{FeCO}_3$). The core value proposition relies on the optical window material’s ability to maintain transparency across broad spectral ranges while preserving the sample environment.

Application Focus: Enabling non-contact spectroscopic characterization (OPTIR, Raman, Far-IR Reflectance) of highly reactive electrochemical materials outside of a glove box environment.
Critical Material Requirement: The Far-Infrared (Far-IR) Reflectance measurements (100-700 $\text{cm}^{-1}$) necessitated the use of a high-purity, thin artificial diamond window (0.4 mm thick).
Performance Validation: The diamond window allowed for high-quality Far-IR reflectance spectra of $\text{Li}_2\text{CO}_3$ powders, with curves measured inside and outside the cell showing excellent overlap.
Optical Purity: Diamond exhibited superior transparency (transmittance $\approx 0.7$) across the entire measured range (400-6000 $\text{cm}^{-1}$), confirming its suitability for multi-modal spectroscopy.
6CCVD Opportunity: The paper highlights the high cost (EUR 480) of the required commercial diamond window. 6CCVD specializes in custom, high-purity MPCVD Single Crystal Diamond (SCD) optimized for demanding optical applications, offering precise thickness control and superior material quality to minimize absorption and interference effects.

Technical Specifications

Parameter	Value	Unit	Context
Diamond Window Diameter	10	mm	Used for Far-IR Reflectance
Diamond Window Thickness	0.4	mm	Used for Far-IR Reflectance
Far-IR Reflectance Range	100-700	$\text{cm}^{-1}$	Primary range requiring diamond transparency
OPTIR Wavenumber Range	920-3100	$\text{cm}^{-1}$	Mid-IR excitation range
Raman Wavenumber Range	50-3600	$\text{cm}^{-1}$	Broad spectral range validated
Diamond Transmittance	$\approx 0.7$	(unitless)	Measured between 400 and 6000 $\text{cm}^{-1}$
Maximum Sample Thickness	1	mm	Constraint imposed by 9 mm objective focal length
Air Tightness Duration	15	days	Confirmed via silica gel color test
Reported Diamond Cost	480	EUR	Commercial window cost

Key Methodologies

The air-tight cell design and experimental validation focused on achieving high spectral quality while maintaining a controlled atmosphere for sensitive battery materials.

Cell Fabrication: Air-tight cells were 3D printed using Polylactic Acid (PLA) polymer, designed using OpenSCAD software.
Sealing Mechanism: Air tightness was ensured by an O-ring (1.5 mm cord diameter) in a static tight configuration, successfully preserving the anhydrous state of silica gel for 15 days.
Window Selection: Four distinct cell designs were developed to accommodate different optical windows ($\text{CaF}_2$, ZnS, $\text{BaF}_2$, and Diamond) based on the required spectral transparency for OPTIR, Raman (visible/Mid-IR transparency), and Far-IR Reflectance (Far-IR transparency).
Far-IR Reflectance: Measurements were conducted using a Nicplan microscope/Thermo Fisher iS50 FTIR spectrometer equipped with a Si Bolometer, operating in the 100-700 $\text{cm}^{-1}$ range.
Sample Preparation: $\text{Li}_2\text{CO}_3$ powders were pressed into a pellet for Far-IR reflectance measurements, comparing spectra acquired outside and inside the diamond-equipped cell.
Data Analysis: Reflectance spectra of $\text{Li}_2\text{CO}_3$ were fitted using the Drude-Lorentz model to extract transverse frequency, plasma frequency, and scattering rate parameters.

6CCVD Solutions & Capabilities

The successful implementation of Far-IR Reflectance spectroscopy on sensitive battery materials hinges entirely on the quality and optical properties of the diamond window. 6CCVD is uniquely positioned to supply the high-specification MPCVD diamond required to replicate and advance this research.

Applicable Materials

The research requires a window material that is highly transparent from the Far-IR (100 $\text{cm}^{-1}$) through the Mid-IR and visible ranges.

Optical Grade SCD (Single Crystal Diamond): This is the ideal material. 6CCVD provides high-purity, low-strain SCD plates with minimal nitrogen incorporation, ensuring the lowest possible absorption in the Mid-IR (1700-4000 $\text{cm}^{-1}$) and Far-IR ranges.
- Advantage: SCD offers superior homogeneity and lower impurity levels compared to the commercial artificial diamond used in the study, minimizing the phonon modes and absorption bands noted by the authors.
Optical Grade PCD (Polycrystalline Diamond): For larger windows (up to 125 mm) or applications where cost is a primary constraint, 6CCVD’s optical grade PCD offers excellent broadband transparency, though with slightly higher scattering than SCD.

Customization Potential

The paper utilized a specific 10 mm diameter, 0.4 mm thick diamond window. 6CCVD specializes in meeting these precise engineering requirements:

Research Requirement	6CCVD Custom Capability
Specific Dimensions	We provide custom plates/wafers up to 125 mm (PCD) and precise laser cutting services to match any required diameter (e.g., 10 mm, 12 mm, 25.4 mm) or complex geometry for custom cell designs.
Thickness Control	We offer SCD and PCD plates with thickness control from 0.1 µm up to 500 µm (0.4 mm used in the paper is well within our standard range), critical for minimizing interference fringes in reflectance measurements.
Surface Finish	Our standard polishing achieves surface roughness $\text{R}_a < 1 \text{ nm}$ for SCD, ensuring minimal light scattering and optimal performance for specular reflectance geometry used in OPTIR and Far-IR.
Metalization	While not required for the optical window, 6CCVD offers in-house metalization (Au, Pt, Pd, Ti, W, Cu) for researchers extending this work to integrated electrochemical cells or heating elements on the diamond substrate itself.

Engineering Support

The development of custom spectroscopic cells for sensitive materials requires deep material science expertise.

Material Selection: 6CCVD’s in-house PhD team can assist researchers in selecting the optimal diamond grade (SCD vs. PCD) and thickness to balance cost, optical performance, and mechanical stability for similar battery material characterization or synchrotron spectroscopy projects.
Interference Mitigation: We provide consultation on how precise thickness control and surface parallelism (Ra < 1 nm) can be leveraged to minimize the interference fringes observed in the diamond window’s reflectance spectra.
Global Supply Chain: We offer reliable global shipping (DDU default, DDP available) to ensure timely delivery of custom diamond components to research facilities and synchrotrons worldwide.

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

View Original Abstract

Material characterization and investigation are the basis for improving the performance of electrochemical devices. However, many compounds with electrochemical applications are sensitive to atmospheric gases and moisture; therefore, even their characterization should be performed in a controlled atmosphere. In some cases, it is impossible to execute such investigations in a glove box, and, therefore, in the present work, an air-tight 3D printed cell was developed that preserves samples in a controlled atmosphere while allowing spectroscopic measurements in reflectance geometry. Equipped with a cheap 1 mm thick CaF2 optical window or a more expensive 0.5 mm thick ZnS window, the cell was used for both optical photothermal infrared and Raman spectroscopy measures; imaging of the samples was also possible. The far-infrared range reflectance measurements were performed with a cell equipped with a diamond window.

Tech Support

Original Source

DOI: https://doi.org/10.3390/instruments8040054

References

2020 - On the challenge of large energy storage by electrochemical devices [Crossref]
2024 - Comprehensive review of lithium-ion battery materials and development challenges [Crossref]
2024 - Polymeric composites in extrusion-based additive manufacturing: A systematic review [Crossref]
2021 - Dual detection of nafcillin using a molecularly imprinted polymer-based platform coupled to thermal and fluorescence read-out [Crossref]
2021 - A low cost microscope prototype [Crossref]
2016 - 3D printed double flow cell for local through-thickness anodization in aluminium [Crossref]