Nanoco

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Nanoco Technologies Ltd. (Nanoco) is a UK-based nanotechnology company that spun out from the University of Manchester in 2001. The company's development has been driven by Dr Nigel Pickett, Nanoco's Chief Technology Officer, whose pioneering work on the patented "molecular seeding" process has formed the basis of Nanoco's unique technology. Since 2004, Nanoco has focussed its research efforts into the development and scale-up of quantum dots and other nanoparticles, including cadmium-free quantum dots. Nanoco's technology has been licensed to Dow, [1] Wah Hong, [2] and Merck, [3] amongst others.

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The company has a production facility in Runcorn, UK.

Nanoco is unique in the nanomaterials market as a company that manufactures large quantities of high grade quantum dots (QDs), in particular cadmium-free quantum dots [4] and other electronic grade nanomaterials.

Market Diffusion

Growing industrial adoption of quantum dot technology by R&D and blue-chip organisations has led to a greater demand for the bulk manufacture of the product. [5] The bulk manufacture of high grade quantum dots provides companies with the platform to develop a wide variety of next-generation products, particularly in application areas such as displays (Quantum dot display), sensors, LED lighting, backlighting, flexible low-cost solar cells and biological Imaging. The ability to scale up the synthesis makes these materials affordable and commercially accessible.

In January 2013, Nanoco announced a licensing deal with the Dow Chemical Company. [6] Following commissioning of Dow's plant in Cheonan, South Korea, Nanoco received its first royalty payment in 2016. [7] Nanoco signed further licensing agreements with Wah Hong [8] and Merck. [9] At the Consumer Electronics Show 2015, improved backlighting using QDs in LCD television sets was a major topic. South Korean (Samsung, LG), Chinese (TCL, Hisense, Changhong) and Japanese (Sony) TV manufacturers had such TVs on display. [10]

In February 2018, the company announced a Material Development and Supply Agreement with an undisclosed US corporation, to scale up and mass-produce novel nanoparticles for advanced electronic devices. [11] Nanoco has since announced agreements with a number of partners relating to development of nanomaterials for use in applications including sensing. [12]

From May 2009 the company has been listed on AIM at the London Stock Exchange , then in May 2015 it moved to the main London Stock Exchange market.

Nanoco Group PLC filed a patent infringement lawsuit against Samsung in February 2020, following a multi-year collaboration at the end of which Samsung launched a TV with quantum dot technology but without entering a license or supply agreement with Nanoco or its partners.

Cadmium-Free Quantum Dots

There is a move towards legislation that restricts or prohibits the use of heavy metals in products such electrical and electronic equipment. In Europe, the restricted metals include cadmium, mercury, lead and hexavalent chromium. [13] Cadmium is restricted 10-fold more than the other heavy metals, to 0.01% or 100 ppm by weight of homogeneous material. There are similar regulations in place, or soon to be implemented, worldwide including in Norway, Switzerland, China, Japan, South Korea and California.

Cadmium and other restricted heavy metals used in conventional quantum dots are of a major concern in commercial applications. For QDs to be commercially viable in many applications they must not contain cadmium or other restricted elements. In response to a push from customers not to include cadmium in household electronics products, Nanoco has developed a range of CFQD® quantum dots, free of any regulated heavy metals. [14] These materials show bright emission in the visible and near-infra-red region of the spectrum.

Nanoco has developed a patented "molecular seeding" method of QD synthesis. [15] Unlike "high temperature dual injection" methods of QD synthesis, the molecular seeding method circumvents the need for a high temperature injection step by utilising molecules of a molecular cluster compound to act as nucleation sites for nanoparticle growth. To maintain particle growth, further precursor additions are made at moderate temperatures until the desired QD size is reached. The process can easily be scaled to large volumes, and is used to produce Nanoco's CFQD® heavy metal-free quantum dots. While the molecular seeding process lends itself to III-V quantum dots, it can be used to produce a wide range of nanoparticle materials.

Sensing

Quantum dots can be use in the sensor industry to extend the range of current CMOS image sensors out into the near-infrared (NIR) and short-wavelength infrared (SWIR) range of wavelengths. Quantum dots can be tuned for specific absorption bands by adjusting the size of the particle and simply applying a layer onto the surface of a CMOS image sensor extends its sensitivity range out to this region. Extending this range allows the sensors to maintain the small pixel size of CMOS image sensors compared to other expensive technology in the NIR region, allowing for higher resolution camera devices at a much cheaper cost.

Applications for NIR and SWIR CMOS image sensors are wide-ranging and include biometric facial recognition, optical diagnostics, LiDAR and night vision.

Lighting

Quantum dots can be used as LED down-conversion phosphors because they exhibit a broad excitation spectrum and high quantum efficiencies. Furthermore, the wavelength of the emission can be tuned completely across the visible region simply by varying the size of the dot or the type of semiconductor material. As such, they have the potential to be used to generate virtually any colour.

Quantum dots are of particular interest for niche lighting applications, including horticultural lighting.

Displays

In recent years, liquid crystal display (LCD) technology has dominated the electronic display device market, with applications ranging from smartphones, to tablets, to televisions. Continual improvements in display quality and performance are sought. The backlighting technology in conventional LCD screens currently uses white LEDs. One of the shortcomings of this technology is that the white LEDs provide insufficient emission in the green and red areas of the visible spectrum, limiting the range of colours that can be displayed. One solution is to integrate QDs into LCD backlight units to improve the colour quality. [16] Green and red QDs can be used in combination with blue LED backlights; the blue light excites the QDs, which convert some of the light into highly pure green and red light to expand the range of colours that the LCD screen can display.

To further improve the performance of QD-based displays, QDs can be patterned at the subpixel level and employed as colour filters at the front of the displays. This architecture may replace the traditional pigment based colour filters, leading to enhanced efficiencies, viewing angles and contrast, as well as the highly saturated colour delivered by the use of QDs.

The display landscape is constantly changing, but with the shift to μ- and mini-LEDs, quantum dots are looking likely to provide the only solution. [17] μLEDs are LEDs with a very small chip size (down to single digit microns) which can be directly used as pixels on a display device. Due to the viewer seeing the LEDs directly this allows for higher contrast, response times and efficiency over traditional LCD technology, and their small size and high power density opens them up for wearable applications such as smartwatches and AR/VR headsets. μLEDs, however, struggle to represent colours across the spectrum with red in particular providing a real challenge for the industry, with traditional colour conversion techniques such as phosphor being insufficient due to physical size constraints. Due to their small size and high absorbance characteristics, quantum dots provide an ideal solution to this issue. A thin layer of quantum dots can be applied to the top emitting surface of the μLED to down-convert the emission to those required for a full colour display. In addition, this technique allows for the colour conversion of blue μLEDs grown on one substrate, eliminating the need to bring multiple coloured LEDs together in an array for a display using expensive and time consuming manufacturing techniques.

Biological Imaging

Over the years, techniques have been developed for medical imaging using fluorescent dyes, as a powerful tool for the diagnosis and treatment of diseases. However, the fluorescent dyes currently used offer poor photostability, with narrow absorption spectra (requiring excitation at a precise wavelength) and/or weak fluorescence due to low extinction coefficients. The development of fluorescence imaging agents using QDs may pave the way for new medical imaging techniques. [18] QDs offer a number of advantageous properties for fluorescence imaging, including high photostability, broad absorption spectra, narrow, symmetric and tunable emission spectra, slow excited state decay rates and high extinction coefficient resulting in strong fluorescence. [19]

The ability to conjugate quantum dots to a wide range of antibodies opens up a variety of applications both in vitro and in vivo, from cell staining, to point-of-care diagnostics, to photodynamic therapy and tumour demarcation.

In 2020, Nanoco received funding from Innovate UK to develop a heavy metal-free quantum dot testing kit for the accurate and rapid detection of SARS-CoV-2 from saliva samples. [20]

Related Research Articles

<span class="mw-page-title-main">Liquid-crystal display</span> Display that uses the light-modulating properties of liquid crystals

A liquid-crystal display (LCD) is a flat-panel display or other electronically modulated optical device that uses the light-modulating properties of liquid crystals combined with polarizers. Liquid crystals do not emit light directly but instead use a backlight or reflector to produce images in color or monochrome. LCDs are available to display arbitrary images or fixed images with low information content, which can be displayed or hidden: preset words, digits, and seven-segment displays are all examples of devices with these displays. They use the same basic technology, except that arbitrary images are made from a matrix of small pixels, while other displays have larger elements. LCDs can either be normally on (positive) or off (negative), depending on the polarizer arrangement. For example, a character positive LCD with a backlight will have black lettering on a background that is the color of the backlight, and a character negative LCD will have a black background with the letters being of the same color as the backlight. Optical filters are added to white on blue LCDs to give them their characteristic appearance.

<span class="mw-page-title-main">Photonics</span> Technical applications of optics

Photonics is a branch of optics that involves the application of generation, detection, and manipulation of light in form of photons through emission, transmission, modulation, signal processing, switching, amplification, and sensing. Photonics is closely related to quantum electronics, where quantum electronics deals with the theoretical part of it while photonics deal with its engineering applications. Though covering all light's technical applications over the whole spectrum, most photonic applications are in the range of visible and near-infrared light. The term photonics developed as an outgrowth of the first practical semiconductor light emitters invented in the early 1960s and optical fibers developed in the 1970s.

<span class="mw-page-title-main">Flat-panel display</span> Electronic display technology

A flat-panel display (FPD) is an electronic display used to display visual content such as text or images. It is present in consumer, medical, transportation, and industrial equipment.

<span class="mw-page-title-main">Quantum dot</span> Zero-dimensional, nano-scale semiconductor particles with novel optical and electronic properties

Quantum dots (QDs), also called semiconductor nanocrystals, are semiconductor particles a few nanometres in size, having optical and electronic properties that differ from those of larger particles as a result of quantum mechanics. They are a central topic in nanotechnology and materials science. When the quantum dots are illuminated by UV light, an electron in the quantum dot can be excited to a state of higher energy. In the case of a semiconducting quantum dot, this process corresponds to the transition of an electron from the valence band to the conductance band. The excited electron can drop back into the valence band releasing its energy as light. This light emission (photoluminescence) is illustrated in the figure on the right. The color of that light depends on the energy difference between the conductance band and the valence band, or the transition between discrete energy states when the band structure is no longer well-defined in QDs.

<span class="mw-page-title-main">Fluorophore</span> Agents that emit light after excitation by light

A fluorophore is a fluorescent chemical compound that can re-emit light upon light excitation. Fluorophores typically contain several combined aromatic groups, or planar or cyclic molecules with several π bonds.

Nanosensors are nanoscale devices that measure physical quantities and convert these to signals that can be detected and analyzed. There are several ways proposed today to make nanosensors; these include top-down lithography, bottom-up assembly, and molecular self-assembly. There are different types of nanosensors in the market and in development for various applications, most notably in defense, environmental, and healthcare industries. These sensors share the same basic workflow: a selective binding of an analyte, signal generation from the interaction of the nanosensor with the bio-element, and processing of the signal into useful metrics.

Nanosys is a nanotechnology company located in Milpitas, California and founded in 2001. The company develops and manufactures quantum dot materials for display products.

<span class="mw-page-title-main">Backlight</span> Form of illumination used in liquid crystal displays

A backlight is a form of illumination used in liquid-crystal displays (LCDs). As LCDs do not produce light by themselves—unlike, for example, cathode ray tube (CRT), plasma (PDP) or OLED displays—they need illumination to produce a visible image. Backlights illuminate the LCD from the side or back of the display panel, unlike frontlights, which are placed in front of the LCD. Backlights are used in small displays to increase readability in low light conditions such as in wristwatches, and are used in smart phones, computer displays and LCD televisions to produce light in a manner similar to a CRT display. A review of some early backlighting schemes for LCDs is given in a report Engineering and Technology History by Peter J. Wild.

A thin-film-transistor liquid-crystal display is a variant of a liquid-crystal display that uses thin-film-transistor technology to improve image qualities such as addressability and contrast. A TFT LCD is an active matrix LCD, in contrast to passive matrix LCDs or simple, direct-driven LCDs with a few segments.

<span class="mw-page-title-main">Photodetector</span> Sensors of light or other electromagnetic energy

Photodetectors, also called photosensors, are sensors of light or other electromagnetic radiation. There are a wide variety of photodetectors which may be classified by mechanism of detection, such as photoelectric or photochemical effects, or by various performance metrics, such as spectral response. Semiconductor-based photodetectors typically use a p–n junction that converts photons into charge. The absorbed photons make electron–hole pairs in the depletion region. Photodiodes and photo transistors are a few examples of photo detectors. Solar cells convert some of the light energy absorbed into electrical energy.

<span class="mw-page-title-main">Cadmium selenide</span> Chemical compound

Cadmium selenide is an inorganic compound with the formula CdSe. It is a black to red-black solid that is classified as a II-VI semiconductor of the n-type. It is a pigment but applications are declining because of environmental concerns

<span class="mw-page-title-main">LED-backlit LCD</span> Display technology implementation

An LED-backlit LCD is a liquid-crystal display that uses LEDs for backlighting instead of traditional cold cathode fluorescent (CCFL) backlighting. LED-backlit displays use the same TFT LCD technologies as CCFL-backlit LCDs, but offer a variety of advantages over them.

<span class="mw-page-title-main">Quantum dot display</span> Type of display device

A quantum dot display is a display device that uses quantum dots (QD), semiconductor nanocrystals which can produce pure monochromatic red, green, and blue light. Photo-emissive quantum dot particles are used in LCD backlights or display color filters. Quantum dots are excited by the blue light from the display panel to emit pure basic colors, which reduces light losses and color crosstalk in color filters, improving display brightness and color gamut. Light travels through QD layer film and traditional RGB filters made from color pigments, or through QD filters with red/green QD color converters and blue passthrough. Although the QD color filter technology is primarily used in LED-backlit LCDs, it is applicable to other display technologies which use color filters, such as blue/UV active-matrix organic light-emitting diode (AMOLED) or QNED/MicroLED display panels. LED-backlit LCDs are the main application of photo-emissive quantum dots, though blue OLED panels with QD color filters are being researched.

<span class="mw-page-title-main">Core–shell semiconductor nanocrystal</span>

Core–shell semiconducting nanocrystals (CSSNCs) are a class of materials which have properties intermediate between those of small, individual molecules and those of bulk, crystalline semiconductors. They are unique because of their easily modular properties, which are a result of their size. These nanocrystals are composed of a quantum dot semiconducting core material and a shell of a distinct semiconducting material. The core and the shell are typically composed of type II–VI, IV–VI, and III–V semiconductors, with configurations such as CdS/ZnS, CdSe/ZnS, CdSe/CdS, and InAs/CdSe Organically passivated quantum dots have low fluorescence quantum yield due to surface related trap states. CSSNCs address this problem because the shell increases quantum yield by passivating the surface trap states. In addition, the shell provides protection against environmental changes, photo-oxidative degradation, and provides another route for modularity. Precise control of the size, shape, and composition of both the core and the shell enable the emission wavelength to be tuned over a wider range of wavelengths than with either individual semiconductor. These materials have found applications in biological systems and optics.

The behavior of quantum dots (QDs) in solution and their interaction with other surfaces is of great importance to biological and industrial applications, such as optical displays, animal tagging, anti-counterfeiting dyes and paints, chemical sensing, and fluorescent tagging. However, unmodified quantum dots tend to be hydrophobic, which precludes their use in stable, water-based colloids. Furthermore, because the ratio of surface area to volume in a quantum dot is much higher than for larger particles, the thermodynamic free energy associated with dangling bonds on the surface is sufficient to impede the quantum confinement of excitons. Once solubilized by encapsulation in either a hydrophobic interior micelle or a hydrophilic exterior micelle, the QDs can be successfully introduced into an aqueous medium, in which they form an extended hydrogel network. In this form, quantum dots can be utilized in several applications that benefit from their unique properties, such as medical imaging and thermal destruction of malignant cancers.

<span class="mw-page-title-main">Carbon quantum dot</span>

Carbon quantum dots also commonly called carbon dots are carbon nanoparticles which are less than 10 nm in size and have some form of surface passivation.

Quantum dots (QDs) are semiconductor nanoparticles with a size less than 10 nm. They exhibited size-dependent properties especially in the optical absorption and the photoluminescence (PL). Typically, the fluorescence emission peak of the QDs can be tuned by changing their diameters. So far, QDs were consisted of different group elements such as CdTe, CdSe, CdS in the II-VI category, InP or InAs in the III-V category, CuInS2 or AgInS2 in the I–III–VI2 category, and PbSe/PbS in the IV-VI category. These QDs are promising candidates as fluorescent labels in various biological applications such as bioimaging, biosensing and drug delivery.

PCO Imaging is a developer and manufacturer of camera systems for scientific and industrial applications.

Light-emitting diodes (LEDs) produce light by the recombination of electrons and electron holes in a semiconductor, a process called "electroluminescence". The wavelength of the light produced depends on the energy band gap of the semiconductors used. Since these materials have a high index of refraction, design features of the devices such as special optical coatings and die shape are required to efficiently emit light. A LED is a long-lived light source, but certain mechanisms can cause slow loss of efficiency of the device or sudden failure. The wavelength of the light emitted is a function of the band gap of the semiconductor material used; materials such as gallium arsenide, and others, with various trace doping elements, are used to produce different colors of light. Another type of LED uses a quantum dot which can have its properties and wavelength adjusted by its size. Light-emitting diodes are widely used in indicator and display functions, and white LEDs are displacing other technologies for general illumination purposes.

Silicon quantum dots are metal-free biologically compatible quantum dots with photoluminescence emission maxima that are tunable through the visible to near-infrared spectral regions. These quantum dots have unique properties arising from their indirect band gap, including long-lived luminescent excited-states and large Stokes shifts. A variety of disproportionation, pyrolysis, and solution protocols have been used to prepare silicon quantum dots, however it is important to note that some solution-based protocols for preparing luminescent silicon quantum dots actually yield carbon quantum dots instead of the reported silicon. The unique properties of silicon quantum dots lend themselves to an array of potential applications: biological imaging, luminescent solar concentrators, light emitting diodes, sensors, and lithium-ion battery anodes.

References

  1. ↑ "Dow to sell, market and manufacture cadmium-free quantum dots for LCD displays | Nanoco Technologies". www.nanocotechnologies.com. Archived from the original on 24 September 2016.
  2. ↑ "Commercialisation Agreement in Display | Nanoco Technologies". www.nanocotechnologies.com. Archived from the original on 10 August 2016.
  3. ↑ "Nanoco and Merck Sign Agreement". August 2016.
  4. ↑ Nanoco - year of progress, "University of Manchester", accessed 22 March 2010
  5. ↑ Who we are and what we do..., "Nanoco", Website Reference, Accessed 26 March 2010
  6. ↑ "Dow to sell, market and manufacture cadmium-free quantum dots for LCD displays | Nanoco Technologies". www.nanocotechnologies.com. Archived from the original on 24 September 2016.
  7. ↑ "First Royalty Payment in Display Market | Nanoco Technologies". www.nanocotechnologies.com. Archived from the original on 10 August 2016.
  8. ↑ "Commercialisation Agreement in Display | Nanoco Technologies". www.nanocotechnologies.com. Archived from the original on 10 August 2016.
  9. ↑ "Nanoco and Merck Sign Agreement". August 2016.
  10. ↑ CES 2015 - Placing bets on the New TV Technologies. IEEE Spectrum, 7 January 2015. Retrieved 12 January 2015
  11. ↑ "Material Development and Supply Agreement". Nanoco Group PLC. 8 February 2018. Retrieved 16 May 2022.
  12. ↑ "Stock". www.lseg.com. Retrieved 16 May 2022.
  13. ↑ Directive 2002/95/EC
  14. ↑ "Cadmium Free Quantum Dots | Nanoco Technologies". www.nanocotechnologies.com. Archived from the original on 9 April 2014.
  15. ↑ I. Mushtaq, S. Daniels and N. Pickett, Preparation of Nanoparticle Material. US Patent 7,588,828, 15 September 2009
  16. ↑ http://www.nanocotechnologies.com/what-we-do/applications/displays [ dead link ]
  17. ↑ Liu, Zhaojun; Lin, Chun-Ho; Hyun, Byung-Ryool; Sher, Chin-Wei; Lv, Zhijian; Luo, Bingqing; Jiang, Fulong; Wu, Tom; Ho, Chih-Hsiang; Kuo, Hao-Chung; He, Jr-Hau (11 May 2020). "Micro-light-emitting diodes with quantum dots in display technology". Light: Science & Applications. 9 (1): 83. Bibcode:2020LSA.....9...83L. doi:10.1038/s41377-020-0268-1. ISSN   2047-7538. PMC   7214519 . PMID   32411368.
  18. ↑ "Biological imaging | Nanoco Technologies". www.nanocotechnologies.com. Archived from the original on 11 April 2014.
  19. ↑ S.B. Rizvi, M. Keshtgar and A.M. Seifalian. Quantum Dots: Basics to Biological Applications. In Handbook of Nanophysics: Nanomedicing and Nanorobotics; K. D. Sattler; Ed.; CRC Press; Boca Raton, Florida, 2010; p. 1.2
  20. ↑ "UKRI".
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