[Reading Science] Find the 'Dream Material' to Save Humanity

Controversy Over Room-Temperature Ambient-Pressure Superconductors Sparks Focus on 'Future Materials'
Active Development of New Materials to Overcome Technical Challenges
Graphene, Maxene, Metamaterials, Perovskite
South Korea Also Launches Full-Scale Effort to Develop Top 100 New Materials

We live in an era where 'materials' determine the future. The recent controversy over room-temperature, ambient-pressure superconductors, which stirred the world, ultimately boiled down to whether a new 'material' had been developed. People, despite not fully understanding what superconductors are, were excited by the hope that they could 'save the Earth' and that 'Korea could become a G1 country.' Theme stocks even emerged and continue to fluctuate. It was a commotion reflecting the times. Many people sense that to overcome humanity’s sustainable development challenges?such as climate change, resource depletion, and environmental pollution?and to survive the fierce competition for technological supremacy, advanced future materials that break existing limits are essential. Let’s explore what kinds of advanced future materials could save humanity.

Schematic diagram of next-generation new material MAX phase - MAX nanosheets vertically aligned side by side along the electric field. Source illustration.

"Means to Solve Technological Challenges"

Currently, the industrial technologies supporting human survival and prosperity have reached their limits. Take semiconductors, for example. Artificial intelligence (AI), autonomous driving, the Internet of Things (IoT), and big data require large capacity and ultra-high-speed performance. Traditional silicon-based semiconductors have improved performance by narrowing circuit linewidths and increasing integration density per unit area, but further miniaturization is no longer possible. At the scale where 2 to 3 atoms function as a single transistor, it has become difficult to control electrical signals so they do not leak elsewhere and operate precisely. Performance degradation and power consumption due to heat generation are also becoming unmanageable. To solve these technological challenges, new materials with completely different characteristics from existing ones are essential. Liquid electrolytes in secondary batteries, which frequently catch fire and have serious safety issues, and conventional solar cells with low efficiency and rigidity have also hit their 'limits.'

Accordingly, scientists are trying to overcome these barriers by creating new materials or synthesizing existing ones to produce materials with entirely different properties. One representative material for 'next-generation solar cells' is perovskite. It is a general term for materials with a molecular structure (so-called ABC3 structure) identified in a mineral discovered in the Ural Mountains by 19th-century Russian mineralogist Lev Perovski. The material consists of two cations each bonded to three oxygen or halogen atoms (Cl, Br, I). Its features include high thermal conductivity and flexibility, making it widely used in solar cell material development. However, it has the drawback of hygroscopicity, absorbing moisture from the air, which causes performance degradation. Currently, the development of next-generation solar cells using perovskite is active, with Korea leading research by achieving the world’s highest photoelectric conversion efficiency (Korea Research Institute of Chemical Technology, 18.24%). Recently, Pohang University of Science and Technology (POSTECH) also developed a perovskite transistor.

Searching for the Best Properties

Graphene, considered the first among 'dream materials,' is another example. It is named after graphite, from which it is made. Graphene is a carbon allotrope composed solely of carbon atoms, like diamond. It forms a two-dimensional planar structure of hexagonal honeycomb shapes connected by sp2 bonds, where three atoms attach at each vertex. Theoretically, it is a thin film one atom thick (about 0.2 nm). Graphene’s properties are so outstanding that it is called the 'best existing' material. It conducts electricity over 100 times better than copper and allows electrons to move over 100 times faster than silicon. Its strength is more than 200 times that of steel, and its thermal conductivity is more than twice that of diamond, the best existing material. It also has excellent elasticity, maintaining its electrical properties even when bent or stretched.

Although theoretically known since 1947, no one could produce it until 2004, when it was discovered that graphene could be simply separated by sticking and peeling Scotch tape from graphite, an achievement that won the 2010 Nobel Prize in Physics. Research and development are underway to apply graphene in various fields such as secondary batteries, touch panels, flexible displays, high-efficiency solar cells, heat dissipation films, coating materials, ultra-thin speakers, electrodes for secondary batteries, and ultra-fast chargers. However, existing processes like chemical vapor deposition, chemical-mechanical methods, and electrochemical oxidation-reduction are complex and costly, making mass production difficult. Therefore, research on mass production processes is ongoing. Graphene is also widely used in medical applications. Due to its superior properties, it complements the shortcomings of existing medical tools and is actively researched as a material for tissue engineering and regeneration of damaged tissues, as well as for treating various bodily diseases.

Human Craftsmanship Challenging the Divine

Metamaterials are also essential to understand in the field of new materials. Metamaterials are artificially created atomic structures that do not exist naturally. At the atomic level, the exact shape, structure, size, and directional arrangement of objects can be freely adjusted to determine the material’s properties. This allows the creation of extraordinary materials with negative refractive indices for energy waves such as light, electromagnetic waves, seismic waves, and sound waves, enabling absorption, reflection, and diffraction. The 'invisibility cloak' from movies has already become a reality. It is a technology that bends light so it does not reflect back, making the wearer invisible to observers. It can be used in military stealth technology. Recently, POSTECH and Samsung Electronics succeeded in making an ultra-thin lens (1 μm) using this technology, providing a solution to the 'camera bump' phenomenon in smartphones. Conventional convex lenses had to be at least 1 cm to focus light. Moreover, metamaterials show limitless potential in electronics, electromagnetics, classical optics, microwave/antenna engineering, quantum electronics, materials science, nanoscience, and semiconductor engineering.

Metamaterial. Reference image.

MXene, a material for which Korean researchers recently acquired mass production technology, is also noteworthy. Discovered in 2011, it is a ceramic material with a two-dimensional planar structure. It refers to new materials composed of atomic layers where transition metals are bonded with carbon or nitrogen. MXene exhibits excellent conductivity, energy storage properties, hydrophilicity, electrochemical sensitivity to gases, and electron absorption ability during friction. It can block electromagnetic waves, purify water, and even block bacteria. It is chemically safe and physically durable, making it one of the strongest materials. It can be used as a material for energy storage devices such as lithium-ion battery electrodes and pseudocapacitors (energy storage devices applying both electrostatic and chemical reactions), as well as for reinforcement composites, catalysts, and filter materials. Its applications are very broad, including desalination, wastewater treatment, wearable frictional electric generators for portable devices, conductive coatings, and sensors.

Meanwhile, Korea is also actively investing in research and development (R&D) at the national level to solve challenges in major science and technology fields. A representative example is the '100 Future Materials Discovery' project announced by the Ministry of Science and ICT in March. The ministry is selecting 100 future materials across 12 national strategic technology fields and is preparing technology development roadmaps from this year through 2025.