Development of Indium Antimonide Quantum Dots via Novel Precursors
The possibilities of infrared imaging in allowing us to see what's invisible to the naked eye are far-reaching, with applications in the consumer, industrial and defence sectors. Quantum dots (QDs), nanoparticles around 1/1000th the width of a human hair, are set to revolutionise the image sensing industry in the coming years, enabling increased efficiency over current silicon photodetectors and spectral tunability into the short-wavelength infrared (SWIR), at a lower cost than InGaAs. With products set to reach the market in 2023, utilising lead-based QDs, sensor manufacturers are already looking towards the next generation of materials to enhance this technology. Indium antimonide (InSb) may offer a heavy metal-free alternative, with exceptionally high carrier mobility and the possibility to extend the detection range into the medium-wavelength infrared (MWIR) to provide a safer alternative to alternative materials, such as lead selenide (PbSe) or mercury telluride (HgTe). However, thus far, scalable methods to synthesise high quality InSb QDs have been hampered by the lack of availability of suitable antimony precursors.
Nanoco Technologies Limited (Nanoco) is a world leader in the synthesis and scale-up of QDs and other nanoparticles, having pioneered the development of cadmium-free QDs using its patented "molecular seeding" technology. Nanoco is working with a number of partners in the image sensor field to tailor its materials for their applications. Building on from Nanoco's experience in developing innovative approaches towards QD synthesis, the aim of the project is to develop three different types of novel antimony precursors, then explore their use to synthesise InSb QDs, with the most successful route being scaled to demonstrate proof-of-concept of the technology. The project innovation will be showcased to customers in the sensor field, for rapid integration and deployment into commercial products.
Potential applications of the project are wide ranging, from machine vision for sorting and quality control, to health monitoring using mobile devices, facial recognition, and sensors for future autonomous vehicles, facilitating positive impacts on the environment, health and security.
Singly-doped Colloidal Quantum Dots for Quantum Technology
Quantum dots (QDs) are excellent platforms for quantum technologies applications. While other types of QDs are already in use for building quantum devices, colloidal quantum dots (CQDs) are exciting alternatives. CQDs demonstrate many of the same desirable quantum mechanical properties as other QD types, but also allow qubit positioning with nanoscale precision, provide a defect-free environment for the qubit, and enable fabrication and incorporation into devices via facile and benign solvent-based techniques. Singly-doped CQDs are particularly good platforms for optically-addressable spin-qubits that will be used in 'quantum repeaters', which are devices for extending the range of quantum communications and for enabling distributed quantum computing. These are both important future applications that will, respectively, ensure secure encryption for financial transactions and for data privacy, and allow new drug molecules to be modelled, fast-tracking their development.
The key challenges in exploiting CQDs for quantum technologies are ensuring that CQDs are singly-doped only, and that dopants remain in the core. Nanoco Technologies Limited (Nanoco) has developed and patented a molecular seeding process that can precisely and stably dope QD cores, with the dopant number controlled by the cluster stoichiometry. However, molecular clusters suitable for singly-doping CQDs have yet to be synthesised. The innovative aim of this project is to develop such clusters, then use the clusters to synthesise singly-doped CQDs, building on Nanoco's existing expertise and IP. Confirming that the CQD cores are singly doped and characterising their properties relevant to quantum technology is demanding and requires the specialised facilities and expertise found in the photon physics group at the University of Manchester (UoM), with which Nanoco has a long-established relationship, and the National EPR facility. A successful project will support the UK's aim to be recognised as a leading nation for developing quantum technologies.
Heavy Metal-Free Quantum Dot Testing Kit for the Accurate and Rapid Visual Detection of SARS-CoV-2 from Saliva Samples
Simple, fast and reliable methods for the detection of SARS-CoV-2, the pathogen that causes Covid-19 in humans are still badly needed to reduce the spread of the pandemic and mitigate its impact on health care systems and on the overall socioeconomic status. Current methods are either complicated and expensive as in the case of PCR; or non reliable and inaccurate as in the case of typical immunoassays. Also, most of the current methods require the use of nasopharyngeal swabs, which can be unpleasant, require training and sending to a specialist laboratory for analysis, often taking several days before results. In this project a point-of-care testing kit will be developed to enable the rapid and easy detection of SARS-CoV-2 or future flu epidemics from saliva samples using a multiplexed immunoassay enabled by fluorescent quantum dot nanoparticles (QDs). Unlike conventional immunoassays that suffer from high inaccuracy, or the PCR methods that suffer from complexity, high cost and result delays, the brightness and multiplexing ability of QDs will provide a reliable detection capabilities that can be performed quickly without prior training and at a lower cost. In this project, a new type of non-toxic QDs (VIVODOTS(tm) nanoparticles) that was developed by Nanoco Technologies, Ltd for biomedical applications will be linked to targeting antibodies against two or more structural proteins in the virus. Once the functionalized QDs with various colour codes come in contact with the SARS-CoV-2 viral particles in the saliva sample, they will bind to the virus and generate unique spectral emission under blue light source. The unique spectral emission will occur only in the presence of the actual virus. The QDs in this type of application offer a number of advantages over conventional fluorescent dyes and colloidal gold, including bright and coded emissions from a single excitation source and low reflectance interference, which is ideal for platforms based on surface detection like lateral flow sticks or paper strips. The proposed concept of this diagnostic kit is versatile and agile as it can be modified quickly to respond to potential future mutations or to new outbreaks caused by other types of contagious pathogens.
Non-invasive, precise and office-based screening procedure for skin cancer using targeted biocompatible quantum dot nanoparticles
There remains an unmet need for patients, health providers and payers to enable precise and simple diagnosis of suspicious skin lesions. In this project we plan to exploit functionalized Vivodots(tm) nanoparticles, a safe and biocompatible type of quantum dots, to develop a non or minimally invasive and office-based procedure for the screening and diagnosis of skin cancers in suspected skin or mucosal lesions.
VIVODOTS™ nano-devices for detection, resection and management of pancreatic cancers
A cancer imaging and therapeutic nano-device will be developed to enable better detection and treatment of lethal types of tumours, particularly pancreatic tumours. The design will be based on the use of biocompatible and fluorescent quantum dot nanoparticles (QDs) equipped with specific cancer targeting molecules. The proposed nano-device will enable more effective pre-, intra-, and post-operative management of pancreatic cancers, resulting in better surgical treatment, higher cure rates, and better quality of life for survivors. Later development should lead to the extrapolation of the same concept to other types of deadly malignancies.
Low Cost Solution Processed CIGS Solar Cells
The market for photovoltaic (PV) modules has grown at 35 % p.a. compound over the past 15 years and will exceed 40 GW in 2014. The drivers behind this extraordinary growth include the rising cost of fossil fuels, concerns over security of energy supplies and worries over climate change. Governments agencies world wide, including the DECC in the UK, are encouraging the deployment of PV through incentives. However as the cost of PV reduces many important regions are now at “grid parity” which removes the need for subsidies. This project will develop a new solution processed thin film photovoltaic device from a nanoparticle precursor, which offers a cheaper route to producing PV modules. The aim of the project will be to integrate technologies developed by the project partners, to improve the efficiency of small area solar cells, then to scale the technology to mini-module dimensions, while maintaining a focus on reducing the cost of the process. The application of the technology to flexible substrates will also be assessed. Lower cost processing of modules will develop a lucrative business for CIGS nanoparticle inks and even greater growth of solar energy deployment.
Cadmium-free quantum dots for cancer diagnostics using fluorescence imaging
Quantum dots (QDs) are fluorescent nanoparticles with unique optical properties which have stimulated wide interest in their use for biomedical diagnostic applications. In this project we will investigate QDs for cancer diagnostics using fluorescence imaging. Sentinel Lymph Node (SLN) mapping is a key technique in cancer therapy (e.g. breast), since identification of potentially malignant lymph nodes followed by surgical excision leads to better treatment with fewer side effects and improved survival. However current SLN mapping techniques using blue dyes and radioactive colloids have several disadvantages. Fluorescence imaging offers improved non-invasive detection capability for SLN mapping. Nanoco has unique patented technology to synthesize cadmium-free fluorescent QDs with low toxicity in large quantities. This project aims to develop functionalised QD reagents with red/NIR fluorescence for SLN mapping and cancer diagnostics using clinically relevant experiments at UCL.
Atomic Layer Deposition coating of quantum dots in beads
GRD Development of Prototype
Nanoco is the sole UK manufacturer and supplier of state of the art quantum dots (QDs), tiny semiconductor crystals only a few nanometers in size. QDs exhibit unusual and interesting energy efficient properties that are exciting commercially in many fast growing markets including electroluminescent displays, solid state lighting, solar cells, biotechnology and biomedicine. The QDs’ many advantages over conventional devices include higher performance, increased efficiency and significantly lower environmental impact. New markets to exploit their unique properties are close to commercial exploitation. The majority of QDs currently in commercial applications contain cadmium (Cd), a toxic heavy metal which is damaging to the environment. New legislation is preventing/minimising the use of Cd worldwide and Japanese companies will not exploit any Cd-based technology. Of necessity biomedical applications require heavy metal free dots. Nanoco has developed proprietary synthetic routes to produce heavy metal free dots of equivalent performance and stability to Cd-based systems in large quantities. However the QDs currently need to undergo intricate and expensive surface modification to improve their stability in air. For commercial exploitation it is essential that the dots can be easily handled by customers (typically giant electronic companies). An alternative process ensuring stability is to coat beads containing the dots with an oxide using Atomic Layer Deposition (ALD).
Nanoco has carried out proof of principle ALD trials with Liverpool University but now needs to develop a process in-house with a modified reactor, prior to industrial scale-up. The ALD coating of Cd-free QDs requires detailed investigation and development. The end result of this project would be the late stage prototype of an industrial scalable process based on ALD of oxides.
The development of alternative, more efficient commercially viable routes to heavy metal-free quantum dot production to exploit developing markets in the electronics industry.
GRD Development of Prototype
Nanoco is the sole UK manufacturer and supplier of state of the art quantum dots (QDs), tiny semiconductor crystals only a few nanometers in size. QDs exhibit unusual and interesting energy efficient properties that are exciting commercially in many fast growing markets including electroluminescent displays, solid state lighting, solar cells, biotechnology and biomedicine. The QDs’ many advantages over conventional devices include higher performance, increased efficiency and significantly lower environmental impact. New markets to exploit their unique properties are close to commercial exploitation.
The majority of QDs currently in commercial applications contain cadmium (Cd), a toxic
heavy metal which is damaging to the environment. New legislation is preventing/minimising the use of Cd worldwide and Japanese companies will not exploit any Cd-based technology. Of necessity biomedical applications require heavy metal free dots. Nanoco has developed proprietary synthetic routes to produce heavy metal free dots of equivalent performance and stability to Cd-based systems in large quantities. However, some of the precursors currently used are both expensive and inefficient. Nanoco must develop the existing process through the introduction of new and efficient precursors to allow QDs to be commercially viable on industrial scale-up and to compete effectively against existing and emerging technologies.
Cost, energy usage and environmental improvements to the process will make their
widespread use possible in current and new electronic and optoelectronic applications.
The synthesis of Cd-free QDs from alternative precursor routes requires detailed investigation and development. In particular new reactor designs will be needed to accommodate the different properties of these new precursors compared to their existing counterparts.
The end result of this project would be the late stage prototype of an industrial scalable
process based on the improved starting materials.
Development of heavy metal-free quantum dots for disease diagnosis, bioimaging and therapy
Water soluble fluorescent semiconductor nanocrystals “quantum dots (QDs)” have been successfully used as tagging agents in biomedical applications. Compared with organic fluorophores, QDs have superior properties that make them excellent tools for addressing challenging biomedical applications that organic dyes and radio isotopes fall short of. However, cadmium in current commercially available QDs prohibits their use in research and medical applications due to the accumulative and toxic properties of this heavy metal. Nanoco has unique patented technology to synthesize heavy metal-free QDs in large quantities and with spectral properties that cover the visible and NIR range. UCL has extensive experience in the treatment and detection of early cancers using fluorescence diagnostic imaging (using porphyrin based compounds) and the expertise of clinical investigators from many specialities. The porphyrins have limited use in surgery as they photobleach unlike the photo-stable QDs. Nanoco will produce water soluble mono-dispersed heavy metal-free QDs with a quantum yield >= 40%. One important output would be a biomedical tracking kit demonstrator. UCL will carry out pharmacokinetic studies of the QDs (fluorescence imaging and spectroscopy). This important assessment of the biodistribution and excretion of QDs would lead to more extensive pre-clinical studies. This would be an iterative process, results from UCL would be fed back to Nanoco to improve the QDs and their resupply would be assessed again. At the end of the project sufficient investigations would have been undertaken to initiate clinical trials at UCL with the wining formulation of QDs.
University of Salford And Nanoco Technologies Limited
Knowledge Transfer Partnership
To develop alternative, more efficient commercially viable routes to heavy metal-free quantum dot synthesis allowing the exploitation of developing markets in the electronics industry.