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.