Ligand- free production of gold nanoparticles


Ref.-No. 3447

The invention related to a process for the preparation of ligand- free gold nanoparticles (Au-NP). The laser fragmentation process makes it possible to produce carbon-free gold nanoparticles (Au-NPs) smaller than 5nm. For this purpose, gold nanoparticles are removed in a liquid medium. Thereafter, repeated laser fragmentation in a free jet of liquid and addition of inorganic oxidizing agents, e.g. Ozone or H2O2 the process carried out by means of a corresponding equipment. It will carry out gold nanoparticles smaller than 5nm  (ø particle size at about 2,5 nm). In addition to the production of gold clusters, the process can also produce ligand-free gold nanocubes.

Keywords: Gold-Nanopartikel, Laserfragmentierung, Liganden freie Gold-Nanopartikel, kleine Nanopartikel, Katalyse , Elektrolumineszenz, Gold nanoparticles, laser fragmentation, ligands, free gold nanoparticles, small nanoparticles, catalysis, electroluminescence

Commercial Opportunities

Au NPs with a size of about 3nm show a sudden change in the physical properties and thus also in the chemical properties in comparison to larger particles.  Ligand- free gold nanoparticles have recently been at the center of intense research, addressing a diverse market. The present invention gives access to large quantities.
Possible applications are in the field of chemistry and pharmacy (heterogeneous and homogeneous catalysis) as well as in biomedical and physical applications (e.g. electroluminescence).


  • Ligand-free production
  • Smaller nanoparticles (<5nm)
  • Small diameter at close distribution
  • New physical and chemical properties
  • Quantitative production

Current Status

The gold nanoparticles can be produced on a laboratory scale. A European and a US patent were granted. On behalf of the University Duisburg- Essen, we offer interested companies the opportunity to license or purchase as well as to further develop the technology.


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