The carbon battle characterization of screen-printed carbon electrodes with SPELEC RAMAN

Importance of the Topic

Carbon-based electrode materials offer exceptional performance in electrochemical applications due to their low cost, chemical inertness, minimal background current and wide electrochemical window. As new carbon nanomaterials emerge, their structural features directly govern physical and chemical properties. Reliable characterization is crucial for selecting the most suitable carbon electrode for sensing, energy storage and other analytical tasks.

Objectives and Study Overview

This work aims to demonstrate how Raman spectroscopy can be employed to distinguish and characterize different screen-printed carbon electrodes. Using DropSens disposable electrodes fabricated with various carbon materials, the study evaluates how Raman band features reflect bond hybridization (sp² vs. sp³), disorder and layer structure, guiding optimal material selection for diverse electrochemical applications.

Methodology and Instrumentation

Raman spectroelectrochemical measurements were carried out with a SPELEC RAMAN system integrating:

• 785 nm laser source (Class 3B)
• Spectrometer covering 785–1010 nm (Raman shift 0–2850 cm⁻¹)
• Bipotentiostat/galvanostat for synchronized optical and electrochemical control

Screen-printed electrodes (refs. DRP-110, DRP-110SWCNT, DRP-110CNT, DRP-110OMC, DRP-110CNF) were mounted in a dedicated Teflon Raman cell and probed via a 785 nm reflection probe. Spectra were recorded using 20 s integration time at the working electrode surface.

Main Results and Discussion

All electrodes exhibit the characteristic G band (~1580 cm⁻¹) indicating sp² carbon domains and the D band (~1300 cm⁻¹) associated with sp³ sites or structural defects. Key observations include:

• Graphite-based electrodes (DRP-110GPH) display a strong, sharp G band and low D/G intensity ratio, reflecting high graphitic order.
• Carbon nanotube-modified electrodes (SWCNT, MWCNT) show narrower D and G bands and a pronounced G′ band (~2600 cm⁻¹), confirming layered tubular structures with fewer defects.
• Ordered mesoporous carbon (DRP-110OMC) and nanofiber (DRP-110CNF) electrodes present elevated D/G ratios, indicating higher defect concentration and increased edge sites.

These spectral differences correlate with electrochemical active area and sensor performance potential.

Benefits and Practical Applications

Raman spectroelectrochemistry provides:

• Non-destructive, rapid assessment of carbon electrode quality and surface structure
• Insight into defect density, hybridization state and layering that influence electron transfer kinetics
• Guidance for tailoring electrode materials in biosensors, environmental monitoring and energy devices

Future Trends and Opportunities

Advances may include in situ Raman monitoring during electrochemical reactions, integration with machine-learning for automated spectral interpretation, and the application of novel hybrid carbon materials (e.g., doped graphene, carbon quantum dots) to further enhance sensitivity and selectivity in analytical platforms.

Conclusion

Raman spectroscopy, when coupled with electrochemical control, proves to be a powerful tool for characterizing screen-printed carbon electrodes. By revealing detailed structural information, it supports the rational design and selection of electrode materials for next-generation sensing and analytical technologies.