Cracking the code of 2D materials: Why clean transfers matter as much as testing

Two-dimensional (2D) materials—atomically thin sheets like graphene and MXenes—have long been hailed as the next big leap in aerospace, flexible electronics, sensors, and integrated circuits. Stronger than steel yet lighter than paper, these materials combine remarkable strength, conductivity, and chemical stability.

But in International Journal of Extreme Manufacturing, a new review argues that the path from lab to industry hinges on something deceptively simple: how cleanly these ultrathin layers are transferred before testing.

The brittle side of wonder materials

Since the isolation of monolayer graphene in 2004, dozens of other 2D materials—ranging from borophene to transition metal dichalcogenides—have been discovered and mass-produced. Their properties make them ideal candidates for high-performance devices. Yet when used in practice, these nanomaterials face unavoidable mechanical stress. Even minor forces can weaken their performance or trigger failure.

Despite their reputation for exceptional strength, 2D materials are inherently brittle. Understanding how they break, bend, or slip under stress is essential for designing reliable devices. That requires accurate mechanical measurements—something easier said than done.

Testing is only as good as the transfer

Researchers typically turn to powerful in situ microscopy techniques such as atomic force microscopy (AFM), scanning electron microscopy (SEM), and transmission electron microscopy (TEM). These tools can probe properties like stiffness and fracture strength at atomic resolution. But all of them depend on one fragile prerequisite: transferring a clean, intact sample onto a substrate without introducing cracks or contamination.

This step is often the Achilles' heel of mechanical studies. For example, MXene nanosheets have yielded wildly different stiffness values depending on the transfer and testing method used. In one study, MoSe₂ samples suffered such high transfer damage that only six intact sheets could be measured. A sample that slips during AFM indentation or carries chemical residues from transfer can skew results significantly.

"Researchers often focus on the glamorous side of in situ microscopy," Prof. Bowei Zhang, lead author of the review, notes, "but the humble transfer step can make or break the experiment."

A call for a unified approach

The review emphasizes that transfer methods deserve equal attention as testing techniques. Whether a material is prepared by exfoliation, chemical vapor deposition, or liquid-phase processing, the choice of transfer must be tailored to preserve cleanliness and integrity. Only then can microscopy yield data that reflect true mechanical behavior.

The authors propose treating synthesis, transfer, and testing not as separate steps but as a single pipeline. Such a systems approach could dramatically improve reproducibility, helping researchers agree on reliable values for mechanical properties.

Beyond numbers: mechanisms that matter

Beyond methodology, the review highlights recent insights into the mechanics of 2D materials. Factors such as fracture dynamics, edge defects, geometric effects, and interlayer bonding play critical roles in how these materials respond to stress. Understanding these mechanisms bridges the gap between basic science and practical engineering, guiding the design of devices that can withstand real-world conditions.

Towards reliable applications

For industries eager to harness 2D materials, the message is clear: performance depends not just on the material itself but on how well we understand—and measure—its mechanics. Clean transfers are not a technical afterthought but a cornerstone of progress.

"The mechanical reliability of 2D materials is the linchpin of their future," says Prof. Zhang. "By refining transfer methods and advancing mechanical testing, we open the door to their widespread use in aerospace, flexible electronics, sensing, and integrated circuits."

With mass production of 2D materials now possible, ensuring their structural integrity has become the next frontier. By spotlighting overlooked challenges and offering practical guidance, this review pushes the field one step closer to transforming scientific promise into industrial reality.

International Journal of Extreme Manufacturing (IJEM, IF: 21.3) is dedicated to publishing the best advanced manufacturing research with extreme dimensions to address both the fundamental scientific challenges and significant engineering needs.

• Maintain #1 in Engineering, Manufacturing for consecutive years
• Average time to First Decision after Peer Review: 34 days
• Open Access Publishing with APC Waivers

Visit our webpage, like us on Facebook, and follow us on Twitter and LinkedIn.