Last week, the Nobel Committees announced the much-anticipated Nobel Prize winners of 2023, honouring the contributions that, as per Alfred Nobel’s will of 1895, “have conferred the greatest benefit to humankind”. In this series of articles, we present selected patents of these winners, that, at least to some extent, result from or lead to their celebrated works. For those with an interest in the most commemorated scientific and technological achievements in 2023 and intellectual property, this series makes for interesting reading.
On 4 October 2023, the Royal Swedish Academy of Sciences announced that the 2023 Nobel Prize in chemistry was rewarded to Moungi G. Bawendi, Louis E. Brus and Alexei I. Ekimov “for the discovery and synthesis of quantum dots”.
The Committee commended that:
… in the early 1980s, Alexei Ekimov succeeded in creating size-dependent quantum effects in coloured glass. The colour came from nanoparticles of copper chloride and Ekimov demonstrated that the particle size affected the colour of the glass via quantum effects.
A few years later, Louis Brus was the first scientist in the world to prove size-dependent quantum effects in particles floating freely in a fluid.
In 1993, Moungi Bawendi revolutionised the chemical production of quantum dots, resulting in almost perfect particles. This high quality was necessary for them to be utilised in applications.
Quantum dots are now used widely in appliances ranging from televisions and LED lamps. They also find applicationin other fields, such as in guiding surgeons when they remove tumour tissues.
Patents
We present herein three patent families. Each of these patent families names one of the winners as an inventor. These patent families may not directly disclose quantum dots, but they invariably relate to nanotechnology.
Alexei Ekimov – Optically reliable nanoparticle based nanocomposite HRI encapsulant, photonic waveguiding material and high electric breakdown field strength insulator/encapsulant
This family of patents claims priority from US Provisional Application No. 60/628,239 and has a priority date of 16 November 2004. US Patent Application No. 11/803,268, for example, has four independent claims. The first two are directed to a high refractive index light path material comprising TiO2 nanoparticles. For example, independent claim 1 recites:
1. A high refractive index light path material comprising:
a) TiO2 nanoparticles having an average primary particle size of less than 40 nm, said TiO2 nanoparticles being treated with 1 to 5 wt % of a group II element;
b) a coupling/dispersing agent coating the treated TiO2 nanoparticles;
c) an optically transparent epoxy into which a multiplicity of the coated treated TiO2 nanoparticles are dispersed.
The third independent claim discloses a method of making such a material:
21. A method of making a reliable high refractive index light path material, comprising the steps of:
a) providing a multiplicity of TiO2 nanoparticles;
a) treating the TiO2 nanoparticles with a group II element;
b) coating the treated TiO2 nanoparticles with a coupling/dispersing agent;
c) dispersing the coated treated TiO2 nanoparticles within an optically transparent silicone so as to form the light path material.
The fourth independent claim discloses a refractive index raising composition:
30. A refractive index raising composition for addition to light path material comprising:
a) nanoparticles having an average primary particle size of less than 40 nm a refractive index greater than 2 and a band gap higher than 2.7 eV;
b) said nanoparticles including 1 to 5 wt % of a group II element;
c) an outer shell-coating disposed around said nanoparticles of a material having a bandgap higher than that of the nanoparticles; and
d) a coupling/dispersing agent coating the treated nanoparticles.
Although this patent family is not directly related to quantum dots, it recognises that the photodegradation characteristics at intensity levels encountered in the proximity of a green-emitting or blue-emitting LED chip are not sufficient to meet the reliability requirement of greater than 65% lumen maintenance under 1000 hours of room temperature operation. It discloses compositionally modified nanoparticles which enhance the photodegradation resistance of nanocomposite ceramers. These nanoparticles have an outer shell-coating of a larger energy bandgap material between the nanoparticle and the coupling/dispersing agent coating, which specifically enables a silicone matrix based nanocomposite ceramer. It was discovered that the compositionally modified nanocomposite ceramer exhibits enhanced photothermal degradation resistance, and the Silicone matrix based modified nanocomposite ceramer exhibits enhanced photothermal degradation resistance, compared to the Epoxy matrix based modified nanocomposite ceramer.
This family was filed as a continuation-in-part application of a PCT application. The PCT application entered national phases in Korea, Europe, China and Japan.
Louis Brus – Method and apparatus for low-temperature fabrication of graphitic carbon, graphene and carbon nanotubes
This family of patents claims priority from US Provisional Application No. 60/818,840 and has a priority date of 6 July 2006. PCT Application No. PCT/US2007/072858, for example, has three independent claims directed to methods of preparing graphitic carbon. Independent claim 1 discloses:
1 . A method for preparing graphitic carbon, comprising: a) combining partially reduced soluble iron, a cyclic nonconjugated polyolefin, and a solvent to form a solution; b) heating the solution until reflux; c) adding an oxidizing agent to the solution to form a second solution; and d) heating the second solution to form a solid, thereby forming graphitic carbon.
The other aspects of the invention include:
23. A method for preparing graphitic carbon, comprising: a) combining bis(cyclooctatetraene)iron (Fe(COT)2), dimethoxyethane (DME), and a solvent to form a solution; b) heating the solution until reflux; c) adding dimethylsulfoxide (DMSO) to the solution to form a second solution; and d) heating the second solution to form a solid,
thereby forming graphitic carbon.
24. A method for preparing graphitic carbon, comprising: a) combining COT with dimethylsulfoxide (DMSO) with a solvent to form a solution, b) heating the solution until reflux; c) adding iron pentacarbonyl (Fe(CO)5) to the solution to form a second solution; and c) heating the second solution to form a solid, thereby forming graphitic carbon.
This patent family discloses techniques for the controllable low temperature fabrication of graphitic carbon. The discovery is based on recognition that the deposition of graphitic carbon through the catalytic decomposition and piecewise reconstitution of hydrocarbons requires the use of high reaction temperatures of 1000 °C or more, or otherwise through the use of forcing chemical reaction conditions. These extreme conditions may be dictated by the need to fragment stable carbon sources and/or by the difficulty intrinsic to ordering the initially prepared carbon network. This patent family also provides a chemical process using commercially available hydrocarbon for the preparation of graphitic carbon, including carbon nanotubes and sheets.
Although not explicitly mentioned in the specification, we believe this invention may serve as a precursor to some quantum dots, for example, carbon nanotube quantum dots.
This family does not appear to have entered national phase in any jurisdiction.
Moungi Bawendi – System and method for large field of view, single cell analysis
This family of patents claims priority from US Provisional Application No. 61/128,838 and has a priority date of 27 May 2008. Granted US Patent No. 8,983,581, for example, is directed to medical imaging systems for intra-operative examination of tissue and identification of target cells in-vivo. For example, independent claim 1 discloses that:
1. A medical imaging system comprising:
an excitation source configured to emit an excitation light towards an object having a plurality of cells that at least one of emit, reflect, and fluoresce light in response to the excitation light;
an optical receptor configured to receive the light from the object;
a filter assembly configured to receive the light from the optical receptor and filter the light;
an image detector having a field of view (FOV) substantially greater than about a diameter of a human cancer cell and configured to have an analysis resolution less than or equal to about the diameter of the human cancer cell, wherein the image detector is further configured to receive the filtered light from the whole FOV simultaneously at the analysis resolution through the filter and analyze the filtered light corresponding to each cell in the FOV, wherein the light received by the image detector is at least one of substantially unmagnified and not magnified; and
a feedback system configured to provide an indication of a cell state and a location in the FOV at the analysis resolution for each cell in the FOV meeting a predetermined condition, wherein the predetermined condition is a threshold light intensity.
In some embodiments, the excitation source is configured to activate an optical probe to emit, reflect and/or fluoresce light. The filter assembly is further configured to distinguish the light from the optical probe from light from the cells being imaged. The optical probes may use luciferase, fluorescence resonance energy transfer (FRET) based, quantum dots, dyes, or any other type of optical detection mechanisms, or a combination thereof. The invention provides a system and method for in vivo analysis of tissue that is capable of analysing a large volume of tissue with sufficient accuracy to provide clinical certainty of tissue pathology.
This patent family was only filed in the US.
The patents and works of Moungi G. Bawendi, Louis E. Brus and Alexei I. Ekimov are well worth a more detailed review for interested parties.