Developing Quantum-Optical Measurements of Excitonic Coherence for Quantum Entanglement in Single Organic Molecules
Lead Research Organisation:
University of Glasgow
Department Name: School of Chemistry
Abstract
Organic semiconductors are carbon-based materials that have found widespread use in organic light emitting diodes, solar cells, lasers, and field effect transistors. Excited electronic states in organic semiconductors are delocalised electron hole pairs, called excitons. Very initially these excitons are formed with their partial molecular orbital contributions all perfectly in phase, a quantum mechanically coherent object. Subsequent interactions with the environment dephase the components, collapsing the exciton wavefunction into a classical object. Measurement of this collapse and identifying chemical structures that can preserve coherence long enough for it to be harnessed for quantum entanglement are very challenging.
In this proposal novel quantum-optical measurements of excitonic coherence in organic semiconductors will be developed. This will be achieved by measuring the second order photoluminescence intensity cross-correlations in a Hanbury Brown and Twiss geometry of single molecules as a function of energy and time. In doing so, state coupling and state coherences will be measured and chemical structures that can preserve them identified. Two systems will be explored, conjugated molecular dyads where strong coupling exists between the states, and covalently linked dimers where exciton delocalisation occurs over larger distances. The valuable new knowledge that is obtained by working at the single molecule level with novel quantum-optical techniques will realise advances in the fundamental understanding of the nature of excitons, and highlight advantageous ways their properties can be chemically engineered for quantum applications.
In this proposal novel quantum-optical measurements of excitonic coherence in organic semiconductors will be developed. This will be achieved by measuring the second order photoluminescence intensity cross-correlations in a Hanbury Brown and Twiss geometry of single molecules as a function of energy and time. In doing so, state coupling and state coherences will be measured and chemical structures that can preserve them identified. Two systems will be explored, conjugated molecular dyads where strong coupling exists between the states, and covalently linked dimers where exciton delocalisation occurs over larger distances. The valuable new knowledge that is obtained by working at the single molecule level with novel quantum-optical techniques will realise advances in the fundamental understanding of the nature of excitons, and highlight advantageous ways their properties can be chemically engineered for quantum applications.
Publications
Altinolcek N
(2021)
A red-orange carbazole-based iridium(III) complex: Synthesis, thermal, optical and electrochemical properties and OLED application
in Journal of Organometallic Chemistry
Hedley GJ
(2021)
Picosecond time-resolved photon antibunching measures nanoscale exciton motion and the true number of chromophores.
in Nature communications
Passadis SS
(2022)
Hafnium(IV) Chemistry with Imide-Dioxime and Catecholate-Oxime Ligands: Unique {Hf5} and Metalloaromatic {Hf6}-Oxo Clusters Exhibiting Fluorescence.
in Inorganic chemistry
Sarcan F
(2023)
Understanding the impact of heavy ions and tailoring the optical properties of large-area monolayer WS2 using focused ion beam
in npj 2D Materials and Applications
Description | Development of spectroscopic methods to measure exciton coherences has begun. Award has primarily been used to fund equipment to enable these techniques to be developed, thus full realisation of this will continue over the proceeding years. |
Exploitation Route | Methods to measure coherence will enable new new communication, computation and electronics technologies to be developed. |
Sectors | Chemicals Digital/Communication/Information Technologies (including Software) Electronics Energy |
Description | EPSRC core equipment: Ultrafast Cryo-Nano Microscope |
Amount | £220,000 (GBP) |
Organisation | Engineering and Physical Sciences Research Council (EPSRC) |
Sector | Public |
Country | United Kingdom |
Start | 01/2023 |
End | 07/2023 |
Description | Watching Energy Flow in Designer Lanthanide Single Molecules: Deterministic or Stochastic? |
Amount | £68,000 (GBP) |
Organisation | The Royal Society |
Sector | Charity/Non Profit |
Country | United Kingdom |
Start | 03/2023 |
End | 04/2024 |
Description | Measuring transition metal dichalcogenides |
Organisation | University of York |
Department | Department of Physics |
Country | United Kingdom |
Sector | Academic/University |
PI Contribution | Measured and analysed FLIM data on damage to WeS2 monolayers that have been FIB'ed |
Collaborator Contribution | Prepared FIB'ed WeS2 monolayers |
Impact | 1st manuscript in advanced preparation, furthers in preliminary development |
Start Year | 2021 |
Description | Single Macrocycle Spectroscopy |
Organisation | University of Oxford |
Department | Department of Chemistry |
Country | United Kingdom |
Sector | Academic/University |
PI Contribution | Measurement of porphyrin oligomers and macrocycles at a single molecule level, with the aim of observing exciton motion and any possible quantum behaviour of it |
Collaborator Contribution | Provided bespoke macrocycle and oligomer materials for measurements, and discussions of scientific conclusions |
Impact | scientific results produced, no outputs yet |
Start Year | 2023 |