Ultra-stable Silver Nanoparticles


Project ID:  D2013-61

Novelty: Highly stable silver nanoparticle clusters with a near quantitative yield through an easy, highly efficient, and commercially affordable synthesis.

Value Proposition: Silver nanoparticles have shown huge technological promise in wide variety of applications due to their superior optical properties, bioactivity, and diversity of chemical and photochemical properties. However, the main challenge with silver nanoparticle is its chemical instability to oxidation, i.e. tarnishing, which has limited the development of technologically important nanomaterials. Despite two decades of synthetic efforts, chemically inert and long-term stable Ag nanoparticles remain unrealized.

Researchers at The University of Toledo have addressed an easy solution to this problem by developing a simple synthetic protocol for producing ultra-stable silver nanoparticles as pure molecular materials and in exceptionally large quantities. The advantages of these silver nanoparticles are:

·        Single-sized and ultra-stable, both in solution and solid forms

·        Near quantitative yield synthesis

·        Easy, simple and inexpensive to synthesize

·        No principle upper limit to the scale of the synthesis due to the exceptional thermodynamic stability of the clusters.

Invention description: Scientists at The University of Toledo have developed an entirely new approach to preparing ultra-stable silver nanoparticles. With judicious choice of solvent conditions and stabilizing agents, the researchers have transformed fragile and unstable Ag complexes into chemically inert materials with unprecedented stability.  The straightforward protocol produces the pure molecular material with no size separations and achieves near quantitative yield in exceedingly large quantities. The stability, purity, and yield of these Ag nanoclusters are substantially better than any other metal nanoparticle, including gold, indicating a different mechanism for stability. Its unique chemical stability and structural, electronic and optical properties are accounted for by a chemically complete structural model and an exceptionally stable Ag32 core, tested by high-level electronic structure theory.

Applications: These nanoparticles find potential use in medical industry, food storage, textile coatings and a number of environmental applications.

Looking for partners: For large scale commercialization of these ultra-stable low cost Ag nanoparticles.


1.      Nature materials 2014. Yoon et al. Hydrogen-bonded structure and mechanical chiral response of a silver nanoparticle superlattice. [Link]

2.      Nature 2013. Desireddy et al. Ultrastable silver nanoparticles. [Link]

IP status: Patent pending

Patent Information:
For Information, Contact:
Stephen Snider
AVP Tech Transfer
The University of Toledo
419 530 6225
Terry Bigioni
Anil Desireddy
Brian Conn