Overview
CEN ISO/TS 21356-1:2022 (adopted from ISO/TS 21356-1:2021) provides a standardized sequence of methods for the structural characterization of graphene produced as powders or in liquid dispersions. The technical specification focuses on characterizing isolated flakes after deposition on substrates and gives suggested measurement protocols, sample-preparation routines, and data-analysis guidance to obtain repeatable, comparable results across laboratories and manufacturers.
Key topics and technical requirements
- Measurands covered: number of layers / thickness, lateral flake size, level of disorder, layer alignment, estimated number fraction of single- and few-layer graphene, and specific surface area.
- Measurement sequence and decision trees: flowcharts help users choose appropriate characterization routes depending on sample type (powder vs dispersion) and initial screening results.
- Screening and rapid tests: includes guidance for a rapid Raman spectroscopy test to detect graphitic material before detailed analysis.
- Analytical techniques: standardized protocols and data-analysis considerations for:
- Raman spectroscopy (rapid screening and detailed assessment of disorder and layer count)
- Scanning electron microscopy (SEM) (morphology and lateral size)
- Atomic force microscopy (AFM) (flake thickness/number of layers)
- Transmission electron microscopy (TEM) (high-resolution structural characterization)
- BET method (Brunauer–Emmett–Teller) for specific surface area of powders
- Sample preparation: recommended routines for preparing dispersions and isolating individual flakes on substrates; annexes include example protocols (SEM/AFM/Raman, TEM, BET) and cleaning/preparation steps for silicon dioxide on silicon wafers.
- Data analysis and uncertainty: annexes provide methods for lateral size and number-fraction calculation, sources of uncertainty and interpretation guidance.
Applications and who should use it
This technical specification is practical for:
- Materials scientists and researchers studying graphene and 2D materials.
- Manufacturers and suppliers of graphene powders and dispersions for quality control and product specification.
- Analytical and testing laboratories establishing validated workflows for graphene characterization.
- Product developers using graphene in composites, flexible electronics, membranes, sensing, and energy storage who need reliable material data.
- Regulators and standardization bodies seeking harmonized measurement approaches for trade and conformity assessment.
Using ISO/TS 21356-1 supports consistent reporting of graphene structural properties, helps answer “What is my material?”, and improves comparability of data across suppliers and labs.
Related standards
Keywords: graphene characterization, structural characterization, powders and dispersions, Raman spectroscopy, SEM, AFM, TEM, BET, lateral flake size, number of layers, graphene nanoplatelets, ISO/TS 21356-1.