Adding foreign atoms to graphene does wonders to boost its properties!

Few materials have stolen the limelight like graphene. Since its discovery, graphene has become the go-to for nearly any technology out there, thanks to its exceptional properties such as high surface area, chemical stability, and high mechanical strength and elasticity. However, despite its seemingly limitless applications, graphene’s potential remains underutilized due to several factors, most notably its single-atom thickness, chemical inertness, and the lack of an energy gap.

One way to overcome these limitations is by integrating graphene with other materials, such as metals, insulators, and semiconductors, to form composite structures with desirable properties. For instance, researchers are adding metal oxides to graphene to create graphene monolayer/metal-oxide nanostructures (GML/MONSs) that have improved physical and chemical properties. However, depositing uniform layers of metal oxides over graphene without disturbing the characteristics of the graphene layer is extremely challenging.

In a new study published in Nano Energy, a team of materials scientists from South Korea has now developed GML/MONSs by using a low-temperature technique known as electrochemical deposition, in which they grew metal-oxide nanostructures exclusively on the native defect sites of graphene. They achieved this by immersing a single-atom-thick graphene layer in a metal-oxide precursor solution. By adjusting the deposition time, the scientists were able to precisely deposit the metal oxide onto the graphene monolayer, creating composite structures with unique properties in the process. “Metal-oxide integrated graphene monolayers with lower densities (≤30 μg/cm²) possess fewer defects, whereas those with higher densities have synergistic characteristics,” explains Professor Sungwon Lee from Daegu Gyeongbuk Institute of Science & Technology (DGIST), South Korea, who was a part of the research team.

By controlling the thickness and density of the metal oxide, the scientists developed high energy density cobalt oxide (Co₃O₄)/GML-based micro-supercapacitors that could be used as a power source, and ultrathin zinc oxide (ZnO)/GML-based photoresistors that possessed excellent flexibility and wearability.

The scientists are excited about the future prospects of their novel methodology. “This new class of heterostructures could be adopted for the fabrication of non-toxic and low-cost energy conversion and storage devices as well as the development of ultrathin, lightweight, and skin-mountable devices that can be integrated with real-time health monitoring systems,” comments Prof. Lee.

The team’s findings pave the way for the development of biocompatible, durable, eco-friendly, and ultralight graphene-based materials.

Reference

*Corresponding author’s email: swlee@dgist.ac.kr

About Daegu Gyeongbuk Institute of Science and Technology (DGIST)

Daegu Gyeongbuk Institute of Science and Technology (DGIST) is a well-known and respected research institute located in Daegu, Republic of Korea. Established in 2004 by the Korean Government, the main aim of DGIST is to promote national science and technology, as well as to boost the local economy.

With a vision of “Changing the world through convergence", DGIST has undertaken a wide range of research in various fields of science and technology. DGIST has embraced a multidisciplinary approach to research and undertaken intensive studies in some of today's most vital fields. DGIST also has state-of-the-art-infrastructure to enable cutting-edge research in materials science, robotics, cognitive sciences, and communication engineering.

Website: https://www.dgist.ac.kr/en/html/sub01/010204.html

About the author

The research work of materials scientists Sungwon Lee, along with Devika and Koteeswara Reddy at the Daegu Gyeongbuk Institute of Science and Technology (DGIST), majorly involves biocompatible and epidermal devices.

Over the course of their research that led to the findings of this study, they and their other colleagues developed a novel and scalable process for the integration of metal-oxides with graphene monolayers. The process involved the fine-tuning of the native defects of graphene, a key factor in the precisely controlled synergistic heterostructure growth, by chemical attachment of low-energy metal and oxide ions.