1. Test items

Structural characteristics detection:

Layer number determination: Atomic force microscopy (AFM) is used to accurately depict the surface morphology of graphene by measuring the interaction force between the needle tip and the atoms on the graphene surface, and then determine its layer number, because graphene with different layers has different performance. Obviously, single-layer graphene often has the best electrical and other properties.

Lattice integrity: Use high-resolution transmission electron microscopy (HRTEM) to observe the lattice stripes of graphene to see if there are defects, dislocations, etc. The perfect lattice structure is the basis for ensuring its high strength and high electrical properties.

Physical performance testing:

Electrical properties: Focus on testing electron mobility. Using the Hall effect measurement system, the magnetic field and current are applied to measure the generated Hall voltage, and the electron mobility is calculated, which is directly related to the application performance of graphene in electronic devices.

Thermal properties: Thermal conductivity testing uses the laser flash method to emit laser pulses to the graphene sample, measure the change in the temperature of the back side of the sample over time, and then calculate the thermal conductivity to understand its heat dissipation capacity.

Chemical performance testing:

Chemical stability: Graphene is placed in different acid-base environments and oxidizing media to observe changes in its quality and structure to determine its ability to withstand chemical corrosion and ensure normal use under complex chemical conditions.

Impurity content: Use inductively coupled plasma mass spectrometry (ICP-MS) to analyze the content of metal impurities and non-metal impurities in graphene. Too much impurities will seriously affect the purity and performance of graphene.

2. Detection Method

Structural property detection: AFM operation requires fine adjustment of the distance between the needle tip and the sample to obtain a clear image; HRTEM requires precise focusing of the electron beam in a high vacuum environment to capture lattice details.

Physical performance testing: The Hall effect measurement system must strictly control parameters such as magnetic field and current intensity; the laser flash method must ensure that the laser pulse energy is stable and the sample and detector are in good contact.

Chemical performance testing: Chemical stability testing must simulate a variety of actual chemical environments; samples must be digested and pre-treated before ICP-MS testing to ensure test accuracy.

3. Testing standards

At present, relevant standards have been gradually established at home and abroad, such as China's "Graphene Material Terminology" and other standards, which regulate the terminology definition, detection indicators, method flow, etc. of graphene. There are also similar IEC and other standards internationally to ensure the accuracy of test results. Comparability and reliability.

4. Detection significance

For scientific research institutions, accurate testing helps to conduct in-depth research on graphene characteristics and promote theoretical breakthroughs; for production companies, it controls product quality, optimizes production processes, and improves market competitiveness; for application companies, it ensures that the purchased graphene meets the requirements and guarantees the quality of end products. Performance; from the perspective of industrial development, testing will safeguard the commercialization and large-scale application of graphene and usher in a new era of materials.