In this blog post, we will learn how the color and transparency of materials are determined by the energy levels and optical properties of electrons.
The Department of Materials Science and Engineering is a major that deals with all kinds of materials we use. At other schools, this department is known as the Department of New Materials Engineering. The Department of Materials Science and Engineering studies the materials we use, broadly divided into metals, ceramics, and polymers (polymer compounds). At Seoul National University, unlike other departments, students do not choose a specific field of study at the undergraduate level, but study all three fields. After that, when you enter graduate school, you choose one of the three fields to study.
Materials engineering plays a very important role in our daily lives. Materials research and development are involved in everything we use, such as smartphones, cars, and medical devices. For example, smartphones require thin, light, yet strong metals and glass, as well as flexible polymer materials. The process of developing and improving these materials is the core of materials engineering. In the case of medical devices, it is important to develop biocompatible materials that are harmless to the human body and can perform their functions reliably.
I am still in my second year, so I have only taken a few classes in the Department of Materials Engineering, but among the subjects I have learned so far, the most impressive one is “Modern Physics of Materials.” This subject looks at materials from a physical perspective. As it is “modern physics,” it analyzes materials from a microscopic perspective, looking at them on a very small scale. I was interested in comparing microscopic phenomena that we cannot see with our eyes and macroscopic phenomena that we can see with our eyes. I liked this course because it was similar to my belief that “what you see is not everything.” I was impressed by how the course explained phenomena that cannot be explained by classical physics, such as electrons passing through walls or substances having wave properties that cause them to split, using microscopic phenomena.
Among the phenomena that cannot be proven macroscopically, this course is particularly effective in explaining the optical properties of materials. This is because most of what we learn in modern physics is about the electrons that make up atoms, and optical phenomena are related to electrons. For example, this course explained why red materials are red and why transparent materials are transparent through the energy levels of electrons. I learned that we can find the unique energy levels of materials and calculate the differences in light energy to determine the corresponding color wavelengths. Through this, I was able to learn how to artificially give materials the colors we want.
Among the experimental equipment, I was particularly interested in the lesson on the principle of the scanning tunneling microscope (STM). Many of the materials we use are utilized at the atomic or molecular level, and even with the most advanced microscopes, it is impossible to see their structure with the naked eye. The scanning tunneling microscope utilizes the property of electrons passing through materials. This phenomenon is called “tunneling,” and by measuring the degree of tunneling, it is possible to understand the structure of these extremely small materials without seeing them with the naked eye.
The Department of Materials Science and Engineering provides systematic education through theory and experiments, teaching students technologies that can be applied to various industries. Through this learning process, students develop the ability to solve various technical problems in the future. Among the courses I have taken so far, I liked the course “Modern Physics of Materials” and the corresponding experiments and experimental tools the most. Although it will be difficult to study because it is invisible, I would like to go to graduate school and conduct research related to this field because of the great sense of accomplishment I get from the research process.
The future of materials engineering is very bright. The role of materials engineering will become even more important in various fields, such as sustainable energy, environmental protection, and advanced technology development. For example, materials engineering will become even more important in the development of next-generation batteries, improving the efficiency of renewable energy resources, and developing biomaterials. Therefore, studying materials engineering will play an important role in leading technological innovation in the future.
