A novel method to fabricate nanostructured bulk materials with tailored grain-boundary conditions


Engineering at the grain boundary - the meeting points of where the crystals or grains of varying size and orientation that comprise a material meet—is crucial to fully utilizing a new material. This area of research is pivotal to fully utilizing the mechanical, electrical, and thermal transport properties of a variety of materials. However, precision grain-boundary engineering is difficult to achieve with current top-down methods.

Ou Chen has invented a process for creating bulk grain-boundary materials from colloidal metal nanocrystals, using surface ligand engineering followed by a pressure sintering process. The resulting materials possess the appearance and conductivity of a metal while maintaining the characteristics of the nanocrystal building blocks.

Market Opportunity

Today’s methods for grain-boundary engineering include electrodeposition, hammering, mechanical alloying, spark erosion, rapid cooling, and sputtering. All these top-down approaches lack precise control of grain boundary conditions. A method for fabricating materials with precisely designed GB conditions would allow engineering to overcome a fundamental hurdle in advancing ground-boundary materials for a variety of practical applications.

Innovation and Meaningful Advantages

Our invention starts with a pressure-sintering method that transforms metal nanocrystals into free-standing grain-boundary materials at the centimeter scale. This method of bottom-up fabrication, which Chen’s team calls an “NC coining” process, involves a ligand exchange of the synthesized metal NCs to replace the native organic capping ligands with small, inorganic ones, followed by a ligand and solvent removal process through washing and drying. The resulting solid NC powder can then go through a pressure sintering step to generate the final bulk GB NC-coins.

This method could be used to produce nano-structured materials with custom grain-boundary conditions, allowing for the optimization of high-hardness materials, strong and anti-corrosive coating materials, as well as solar cell, photovoltaic, phonon-voltaic, electrode, magnetic, spintronics, battery, and optical materials.

Collaboration Opportunity

We are seeking an investment opportunity to further develop this innovative technology.

Principal Investigator

Ou Chen, PhD
Associate Professor of Engineering
Brown University

IP Information

US Patent 11,607,733, Issued March 11, 2023



Victoria Campbell, PhD
Director of Business Development
Brown Tech ID 3042
Patent Information:
For Information, Contact:
Brown Technology Innovations
350 Eddy Street - Box 1949
Providence, RI 02903
Ou Chen
Yasutaka Nagaoka
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