Hiroshi DAIMON
Head Investigator of Grand-in Aid for Scientific Research on Innovative Area "3D Active-Site Science"
Graduate School of Materials Science, Nara Institute of Science and Technology, Professor

The year 2014 was the International Year of Crystallography and marked the centennial of the birth of modern crystallography. In 1914, Laue solved the mechanism of the X-ray diffraction from crystals and was awarded the Nobel Prize in Physics. Crystals are present in many items around us, such as precious stones and snow. The Bragg duo (father and son) clarified the crystal structure  of salt through X-ray diffraction and was awarded the Nobel Prize in Physics in 1915. Since then, materials science has achieved an exponential growth by revealing the atomic arrangement of crystal structures, and the three-dimensional (3D) atomic arrangements became to be understood for inorganic materials, organic materials, and even protein structures. Consequently, by understanding the activity of life at a molecular level, it is possible to transform life and even design medicines. Even Laue did not expect crystallography to grow to this extent. It is very important to consider the atomic arrangement and understand the mechanisms of the functional materials before pursuing their practical industrial applications.

However, there are few methods for viewing the 3D atomic arrangement of materials that are not in crystal form. Most materials are not crystalline, and in many cases, a function can only work when impurities (dopants) are added. For example, n-type and p-type semiconductors are usually created by adding a dopant to silicon crystals. However, it is impossible to see how the dopant atoms are arranged inside the crystals using X-ray diffraction. For a long time, we have searched for the optimal doping conditions without knowing the atomic arrangement around dopant.

Although the active-sites such as the dopant inside the crystal, the reaction center of the catalyst, the atomic structure of the interface, and the reaction center of photosynthesis are important for modern technology, it is hard to see the 3D atomic structures around active-sites directly.  However, using X-ray fluorescence holography , neutron holography, photoelectron holography, CTR scattering, and the electron diffraction imaging of 3D active-sites, it is possible to visualize the atomic structures of these non-crystalline materials. By viewing these structures, we can understand their material properties, which will advance our research  and daily life significantly. The study will certainly evolve and be widely pursued in future as the progressive development of X-ray diffraction.

With the atomic resolution holography study group that was formed in 2008 as a parent body, we have worked with many researchers to promote active research programs. In an extremely broad range of fields such as inorganic materials, organic materials, and bio-materials, we observe the active-sites where the physical properties function and understand the mechanisms of functionalities by combining first-principle calculations with observations. Then, we create more sophisticated materials and apply them industrially. The 3D Active-Site Science brought the Japanese researchers together, aiming a large paradigm shift. The objective of this new academic field is to create an “Active-Site Science” to investigate the physics of the “non-crystalline local atomic structure,” which could not hitherto be dealt with. Furthermore, we aspire to nurture the next generation, who will play a leading role in bringing about breakthroughs and new science in this field.