When engineers use lasers to “repair” graphene oxide, they usually expect the material to become cleaner, more conductive, and ultimately more reliable. But what if removing defects actually makes the material fail sooner?
Publishing in Nano Research on June 26, 2026, scientists from the University of Science and Technology of China (USTC) have discovered that laser reduction can significantly shorten the fatigue lifetime of graphene oxide, despite apparently reducing its defect level according to conventional Raman measurements. Their study reveals that the long-term mechanical reliability of graphene oxide depends not simply on how many defects remain, but on what kinds of defects survive the laser treatment .
Graphene oxide (GO) is a chemically functionalized two-dimensional material widely used in flexible electronics, sensors, and microelectromechanical systems (MEMS). Because its properties can be continuously tuned by removing oxygen-containing functional groups, laser-induced reduction has become one of the most widely adopted approaches for localized patterning and property engineering. In many laboratories, the Raman laser used for structural characterization can itself act as a localized reduction stimulus.
While previous studies have focused primarily on restoring electrical conductivity and modifying the chemical composition of graphene oxide, much less is known about how laser processing influences its long-term mechanical reliability. This question is particularly important because flexible devices often experience millions or even billions of loading cycles during service.
To answer this question, the researchers combined Raman spectroscopy, nano-infrared spectroscopy (nano-IR), X-ray photoelectron spectroscopy (XPS), and atomic force microscopy (AFM)-based fatigue testing to directly correlate chemical evolution with mechanical behavior.
“We found that Raman laser irradiation is not merely a characterization tool—it also acts as a controllable chemical stimulus,” said Prof. Guorui Wang, the corresponding author of the article. “More importantly, laser reduction does not simply reverse the oxidation process.”
The team discovered that laser irradiation selectively removes epoxide functional groups , while vacancy defects largely remain and progressively accumulate. Nano-IR chemical mapping directly visualized the selective disappearance of epoxide-related signals, whereas hydroxyl and carboxyl groups remained largely unchanged. Complementary XPS measurements further confirmed the preferential removal of epoxide-related oxygen species.
This selective chemical evolution has profound mechanical consequences. AFM fatigue experiments showed that laser-reduced graphene oxide exhibits significantly shorter fatigue lifetimes than oxidized graphene oxide, even when both materials display similar Raman defect metrics. Moreover, the fatigue failure mode changes dramatically from localized damage accumulation in oxidized GO to brittle fracture after laser reduction.
The researchers attribute this unexpected behavior to two coupled processes. The first author, Zhehan Xue, a doctoral candidate at USTC, commented, “during laser reduction, vacancy defects continue to accumulate, creating favorable sites for crack initiation, while epoxide groups—which help arrest crack propagation and improve damage tolerance—are selectively removed. Together, these changes fundamentally weaken the material’s resistance to cyclic loading.”
The co-first author, Dr. Yafei Wang, a postdoc at USTC, added that “Traditionally, researchers have evaluated graphene oxide using Raman defect parameters such as the I D / I G ratio. Our work shows that these metrics alone cannot predict fatigue reliability. The chemical identity and evolution history of defects are equally important.”
The study establishes a direct link between laser-induced chemical modification, defect evolution, and fatigue reliability, revealing the chemical origin of fatigue degradation in graphene oxide. Beyond graphene oxide itself, the researchers believe the findings provide a new framework for understanding how chemical functionalization influences the long-term durability of two-dimensional materials.
As chemically engineered 2D materials continue to find applications in flexible electronics, MEMS, wearable devices, and other technologies subjected to repeated mechanical loading, the work offers new guidance for designing materials that are not only functional, but also mechanically reliable over their service lifetime.
The Institute of Micro and Nano Composites (IMNC: imnc.ustc.edu.cn) at the University of Science and Technology of China (USTC) is dedicated to understanding the mechanics of materials and interfaces across multiple length scales, from atoms and molecules to macroscopic structures. The institute develops advanced micro/nanoscale mechanical testing techniques, combined with Raman spectroscopy, atomic force microscopy, and in situ electron microscopy, to investigate deformation, fracture, fatigue, and interfacial mechanics in low-dimensional materials, functional materials, and nanocomposites. By integrating fundamental mechanics with materials science, IMNC aims to establish structure–property relationships and develop reliable materials for next-generation flexible electronics, energy devices, aerospace structures, and other extreme applications.
DOI Link:
https://doi.org/10.26599/NR.2026.94908972
About Nano Research
Nano Research is a peer-reviewed, open access, international and interdisciplinary research journal, sponsored by Tsinghua University and the Chinese Chemical Society, published by Tsinghua University Press on the platform SciOpen. It publishes original high-quality research and significant review articles on all aspects of nanoscience and nanotechnology, ranging from basic aspects of the science of nanoscale materials to practical applications of such materials. After 18 years of development, it has become one of the most influential academic journals in the nano field. Nano Research has published more than 1,000 papers every year from 2022, with its cumulative count surpassing 8,000 articles. In 2025 InCites Journal Citation Reports, its 2025 IF is 9.4 (8.3, 5 years), and it continues to be the Q1 area among the four subject classifications. Nano Research Award, established by Nano Research together with TUP and Springer Nature in 2013, and Nano Research Young Innovators (NR45) Awards, established by Nano Research in 2018, have become international academic awards with global influence.
Nano Research
Selective laser reduction uncovers why graphene oxide becomes more vulnerable to fatigue
26-Jun-2026