Blue luminescence discovered for the first time at the graphene-boron nitride interface.
Electrons are concentrated at the boundary, creating new energy levels.
Flexible materials such as graphene and hexagonal boron nitride
Next-generation displays that fold or bend can be created


A research team led by Professor Shin Hyun-seok of the Ulsan National Institute of Science and Technology (UNIST) announced on the 27th that they have discovered, for the first time, a blue luminescence phenomenon at the interface between graphene and hexagonal boron nitride, also known as "white graphene." Furthermore, they successfully fabricated a flexible light-emitting device using "graphene quantum dots," demonstrating graphene's potential as a new display light source.

Graphene is a thin film of carbon atoms arranged in a hexagonal pattern. Despite its thinness, it is strong, flexible, and highly conductive, both thermally and electrically. It's often called the "dream material," and research is actively underway across various industries. To increase the density (luminescence intensity) of the interface, the research team used a method of stacking boron nitride films with graphene layers less than 20 nm (nanometers, 10-9 m) thick.

Graphene has not been studied much as a light-emitting material for display devices because it lacks an energy bandgap, which determines the color of light emitted by the material.

However, the research team analyzed the electron energy within the materials based on the results of observing with an electron microscope that the structure of the two materials, which were originally in a straight hexagonal shape, changed into pentagonal and heptagonal shapes at the boundary. As a result, it was concluded that the cause of the luminescence phenomenon was the creation of a new energy level as electrons (charges) were concentrated at the boundary.

Professor Shin said, “This study is very significant in that it shows that the interface between graphene, a conductor, and boron nitride, an insulator, can be used as a light source material,” and added, “This study is expected to greatly contribute to the development of the flexible display industry by implementing optoelectronic devices such as optical sensors and LEDs based on these two-dimensional composites.”

Meanwhile, the results of this study, in which Professor Jeon Seok-woo of KAIST and Professor Son Byeong-hyeok of Seoul National University participated, were published in the international academic journal 'Nature Communications' on October 23.