Crystalplex Corp. has announced the U. S. Patent and Trademark Office (USPTO) issued U. S. Patent No. 9,425,253, “Passivated Nanoparticles,” assigned to Crystalplex. The patent, which claims the fabrication and use of SapphireTM quantum dots, or passivated quantum dots with improved stability, was granted to inventors Lianhua Qu and Gregory Miller.
The patent is directed to processes for synthesizing an alloy gradient nanoparticle with a Zn:S shell and an outside coating of aluminum oxide that provides a barrier to environmental degradation. In addition to providing improved photo, thermal, and environmental stability, the quantum dots demonstrate longer lifetimes, as the optically transparent aluminum oxide outer layer serves as a shield against degradation by humidity and oxygen. The passivation technology is applicable to Crystalplex’s alloy gradient cadmium-free quantum dots, as well.
“The protection provided by the Sapphire™ quantum dot shell makes passivated nanoparticles particularly well suited to the demanding requirements of optoelectronic applications,” said Dr. Qu, Chief Technical Officer at Crystalplex Corp. “They have proven to be quite resilient.” In August, Dr. Qu presented his findings on the use of passivated quantum dots in a thermally processable matrix at the 26th International Liquid Crystal Conference (ILCC) at Kent State University in Ohio. (See Dr. Qu’s technical paper www.crystalplex.com and click on Technological Developments)
“The granting of the passivation patent further strengthens our robust patent portfolio,” said Crystalplex CEO Matt Bootman. In addition, these air-stable quantum dots have been melt processed in polymer substrates. To our knowledge no other manufacturer’s quantum dots can withstand such extreme heat.” (See video of quantum dot/polymer composite being co-extruded with PMMA at over 200°C: at crystalplex.com/#LiveContent[quantumdots])
