Background

Transparent conductors are commonly made of Indium Tin Oxide (ITO), however, ITO is fairly brittle and is not suitable for flexible devices. Copper nanowires achieve excellent thermal and electrical conductivity and have the necessary ductility for flexible interconnects; however, copper is extremely vulnerable to contact with oxygen, which rapidly causes oxidation and consequently significant degradation of the desirable properties thermal and electrical conductivity of copper.

A common technique to reduce copper oxidation is coating the nanowires with silver, but current industrial processes require ammonia‑based reactions which are not environmentally friendly. This technique from Portland State researchers allows for highly scalable manufacture of silver coated copper nanowires without the use of ammonia.

Technology Overview

The inventors have developed an eco-friendly fabrication of silver coated copper nanowires and a preparation method thereof to replace ammonia with eco- friendly chemical, methylsulfonylmethane (DMSO₂), through a low‑temperature (<100C) solution-based method that does not require an electroplating step or use of ammonia reagents.

DMSO₂ is widely considered a safe chemical (having GRAS designation in the USA).

The copper nanowires a produced in solution and then can be immediately coated with silver using what is commonly called a “one pot” method, which, along with the scalability of the method, provides high quality silver coated copper nanowires at much lower manufacturing cost.

Benefits

Copper Nanowires are made in solution first, with length and aspect ratio “tunable” according to the reagent/reaction conditions.

A “one‑pot” method for both nanowire growth and silver coating steps minimizes manufacturing costs (capital equipment, energy, and waste costs). No electrolysis step reduces batch time and manufacturing costs.

Elimination of ammonia as a reagent reduces both environmental and manufacturing safety concerns

Applications

Transparent display technologies
Touch screen devices
Flexible electronics (wearable devices, flexible cable connects, strain sensors)
Solar Panels

Opportunity

Looking for licensing opportunities with companies interested in scale up and design for manufacturing. Exclusive worldwide licensing currently available.

Ammonia-free Silver Coated Copper Nanowires

IP Status

Seeking