2026-07-15 シカゴ大学
University of Chicago chemists have shown how to make nanocrystals from a useful class of materials known as metal nitrides—a previously impossible task. Above, an electron microscope image of the crystals, which are so small that billions could fit on your fingernail.Image courtesy Ruiming Lin
＜関連情報＞
- https://news.uchicago.edu/story/chemists-shrink-gallium-nitride-material-behind-led-lighting-nanocrystals
- https://www.nature.com/articles/s41586-026-10801-3
- https://www.nature.com/articles/nature21041
アンモニア圧が溶融塩中のコロイド状金属窒化物合成を制御する Ammonia pressure controls colloidal metal nitride synthesis in molten salts
Ruiming Lin,Vikash Khokhar,Ningxin Jiang,Wooje Cho,Zirui Zhou,Di Wang,Justin C. Ondry,Zehan Mi,James Cassidy,Alex M. Hinkle,Alexander S. Filatov,John S. Anderson,Richard D. Schaller,De-en Jiang & Dmitri V. Talapin
Nature Published:15 July 2026
Abstract
Metal nitrides represent a large class of materials with extensive applications in optoelectronics, energy and healthcare technologies. For example, GaN and related nitride semiconductors are key materials for solid-state lighting and high-power electronics1,2. TiN and other early transition metal nitrides (TMNs) are widely used in wear-resistant alloys, tool coatings, catalysts and medical implants3. Strong metal–nitrogen bonds grant nitrides structural rigidity as well as chemical and thermal stability4. However, the covalency of metal–nitrogen bonds necessitates high temperatures to synthesize crystalline metal nitrides. Common synthetic routes include high-temperature solid-state nitridation5, crystal growth in supercritical ammonia6, molecular-beam epitaxy (MBE)7, reactive sputtering8,9 and chemical vapour deposition1,10,11,12. The solution synthesis of colloidal nanocrystals (NCs) has been demonstrated for late TMNs with relatively weak chemical bonds13,14,15,16,17, whereas the synthesis of early TMN NCs is challenging because it requires temperatures far above the stability range of commonly used solvents. Here we report a general approach to solution synthesis of refractory metal nitride NCs by reacting metal halides and ammonia dissolved in molten inorganic salts at elevated pressures. Successful syntheses of colloidal TiN, VN, GaN, NbN, Mo2N, Ta3N5, TaN, W2N and ternary Ti1−xVxN NCs are demonstrated. These NCs expand the scope of solution-processable technologically important materials.
溶融無機塩中の安定コロイド Stable colloids in molten inorganic salts
Hao Zhang,Kinjal Dasbiswas,Nicholas B. Ludwig,Gang Han,Byeongdu Lee,Suri Vaikuntanathan & Dmitri V. Talapin
Nature Published:16 February 2017
DOI:https://doi.org/10.1038/nature21041
Abstract
A colloidal solution is a homogeneous dispersion of particles or droplets of one phase (solute) in a second, typically liquid, phase (solvent). Colloids are ubiquitous in biological, chemical and technological processes1,2, homogenizing highly dissimilar constituents. To stabilize a colloidal system against coalescence and aggregation, the surface of each solute particle is engineered to impose repulsive forces strong enough to overpower van der Waals attraction and keep the particles separated from each other2. Electrostatic stabilization3,4 of charged solutes works well in solvents with high dielectric constants, such as water (dielectric constant of 80). In contrast, colloidal stabilization in solvents with low polarity, such as hexane (dielectric constant of about 2), can be achieved by decorating the surface of each particle of the solute with molecules (surfactants) containing flexible, brush-like chains2,5. Here we report a class of colloidal systems in which solute particles (including metals, semiconductors and magnetic materials) form stable colloids in various molten inorganic salts. The stability of such colloids cannot be explained by traditional electrostatic and steric mechanisms. Screening of many solute–solvent combinations shows that colloidal stability can be traced to the strength of chemical bonding at the solute–solvent interface. Theoretical analysis and molecular dynamics modelling suggest that a layer of surface-bound solvent ions produces long-ranged charge-density oscillations in the molten salt around solute particles, preventing their aggregation. Colloids composed of inorganic particles in inorganic melts offer opportunities for introducing colloidal techniques to solid-state science and engineering applications.
