Colloidal quantum dots (CQDs) and related materials are nanoscale semiconductor crystals that represent an exciting frontier in solution-processed materials. Their size-tuneable optical properties and unique quantum behaviour make them highly versatile for advanced photonic applications, including light-emitting diodes (LEDs), high-speed colour converters for displays and lighting, lasers, and single-photon sources.

This PhD project builds on recent advances in the synthesis, assembly, and characterisation of CQDs organized into supracrystals or supraparticles - hierarchical structures where nanocrystals act as building blocks or “nanobricks.” ^1-2 Supracrystals are highly ordered, densely packed assemblies that exhibit emerging collective optical behaviours, including enhanced fluorescence and laser oscillation. Our team has developed emulsion-templated self-assembly processes to fabricate semiconductor supracrystals from the bottom up, successfully demonstrating microlasers produced in this way. In parallel, we are exploring hybrid structures and top-down fabrication methods to expand the design space.

A key focus of our current efforts is the creation of multifunctional supraparticles (SPs) by blending different types of nanobricks. We are tailoring the geometry and design of SPs, for example, coupling them to plasmonic structures or upconverting nanoparticles, and engineering their surface chemistry to unlock new functionalities. Recent achievements include SP microlasers functionalized with biomolecular probes, SPs coupled to optical waveguides, and assemblies capable of emitting at multiple wavelengths. Building on this foundation, we are now extending our approach to a broader range of materials and applications. The overarching goal of this PhD project is to fabricate and study quantum-dot SPs with superior light emission properties, aiming to advance the state of the art in temporally controlled, ultra-bright microscopic photonic sources. If successful, the outcomes could have significant impact across optical communications, biological and chemical sensing, photocatalysis, and quantum photonics.

The project will pursue three key objectives:

1. Synthesis and characterisation of CQDs and supracrystals: The student will develop and refine protocols for synthesizing CQDs and/or directing their controlled self-assembly into hybrid supracrystals.
2. Studies of fluorescence, laser oscillation, and non-classical emission: By carefully designing supracrystals, the researcher will demonstrate fluorescence enhancement and target laser oscillation with reduced thresholds, enabling efficient microscopic laser sources for both classical and quantum applications.
3. Investigation of non-toxic CQD materials: To address environmental concerns associated with cadmium- or lead-based CQDs, the project will explore alternative, less toxic materials, assessing whether they can match the performance of conventional systems while contributing to safer, sustainable photonic devices.

Depending on the candidate’s interests, there will be opportunities to explore applications such as biological and chemical sensing, optical communications, or single-photon sources.³ The student will join the Colloidal Photonics team at the Institute of Photonics, which develops novel technologies for medicine, environmental monitoring, industry, and digital lighting. This interdisciplinary environment will provide a strong foundation for mastering quantum dot synthesis, functionalization, and assembly.

By leveraging expertise in nanoscale control and material design, this project will push the boundaries of what is possible with colloidal quantum dots, paving the way for more efficient, robust, and scalable photonic devices.

Institute of Photonics

The Institute of Photonics (IoP), part of the Department of Physics, is a centre of excellence in applications-oriented research at the University of Strathclyde. The Institute’s key objective is to bridge the gap between academic research and industrial applications and development in the area of photonics. The IoP is located in the £100M Technology and Innovation Centre on Strathclyde’s Glasgow city centre campus, at the heart of Glasgow’s Innovation District, where it is co-located with the UK’s first Fraunhofer Research Centre. Researchers at the IoP are active in a broad range of photonics fields under the areas of Photonic Devices, Advanced Lasers and Neurophotonics. Please see our research for more information.

Strathclyde Physics is a member of SUPA, the Scottish Universities Physics Alliance.

The University of Strathclyde has been the recipient of the following awards: UK University of the Year 2026 (Daily Mail University Guide); Scottish University of the Year 2026 (The Times and Sunday Times Good University Guide); The Queen’s Anniversary Prizes for Higher and Further Education 1996, 2019, 2021 & 2023; University of the Year 2012 & 2019 (Times Higher Education).

References

1. P. U. Alves, B. J. E. Guilhabert, J. R. McPhillimy, D. Jevtics, M. J. Stratin, M. Hedja, D. Cameron, P.R. Edwards, R. W. Martin, M. D. Dawson, and N. Laurand: Waveguide-integrated colloidal nanocrystal supraparticle lasers, ACS Applied Optical Materials, Vol. 1, No. 11, 24.11.2023, p. 1836-1846.
2. C. J. Eling, N. Bruce, N.-K. Gunasekar, P. U. Alves, P. R. Edwards, R.W. Martin, and N. Laurand: Biotinylated photocleavable semiconductor colloidal quantum dot supraparticle microlaser, ACS Applied Nano Materials, Vol. 7, No. 8, 26.04.2024, p. 9159-9166.
3. Tingting Yin, Xiao Liang, Yuqing Huang, Yi Tian Thung, Zhenhua Ni, Handong Sun, and Hilmi Volkan Demir: Engineering Colloidal Quasi-2D Quantum Wells for High-Performance Room-Temperature Single-Photon Sources, Journal of the American Chemical Society 2025 147 (38), 34540-34547 DOI: 10.1021/jacs.5c08797.