Exciton Science is creating new materials for solar energy conversion and efficient, next-generation light-emitting devices to improve the ways we harness and use light energy
We are building the ultimate light-harvesting system by efficient conversion and transport of excitons
The solar spectrum arrives at the Earth’s surface as broadband white light, characterised by the sun’s temperature of 6,000 kelvin, providing more energy than we could ever use. It contains all the colours of the rainbow, as well as colours we can’t see, like ultraviolet and infrared. Most solar panels can only use near-infrared light. In this platform, we’re discovering ways to get around this limitation by converting low-energy Coherent Control of Excitons photons of light into high-energy photons that can be captured by solar panels and turned into electricity.
The next generation of solar panels will match or surpass silicon in efficiency, while offering greater flexibility. Thanks to advanced liquid synthesis and printing technology, they will require less energy to make and be easier to decommission and recycle at the end of their lifespan. In this platform, we’re working closely with CSIRO to gain a greater understanding of these new materials and manufacturing techniques. And we’re significantly accelerating the discovery and testing process through automation and infrastructure that is unique in global solar photovoltaics research.
The realisation of any excitonic device or technology requires control over excitons.
Excitons are quasiparticles created when a material is stimulated by light. We need to know more about the behaviour of excitons - how far, how quickly and to which location they move, and how they interact with each other and their immediate environment. If we can control them better, we may be able to take advantage of a process known as singlet fission, which allows for more than one exciton to be generated by a single optical event. This offers us a pathway to developing more efficient solar energy devices, together with applications in optical molecular switching, magnetometry and spin-based logic at the quantum scale.
In next-generation solar panels, LEDs and other advanced technology, many imperceptible but crucial processes occur at ‘interfaces’, the precise point where one material is joined to another. In this platform, we’re working to better understand and influence the location and lifetime of excitons, and optimise the interfaces that are vital to prevent losses and maximise the efficiency of devices. But this is no easy task – you can’t observe these processes with normal microscopes, so we need super-resolution technology to probe below the diffraction limit of light and gain more insight into conditions at the nanoscale.
The behavior of excitons is governed by quantum mechanics, and if you’ve ever been stumped by the ambiguous status of Schrödinger's cat, you’ll know how complicated things can get. To find out more about what excitons do in materials and across interfaces, we need to develop advanced computational techniques and different theoretical approaches to investigate the interplay between electronic coupling, spin and structure. The goal is to create modelling methods that can interpret and predict exciton behavior in materials on scales ranging from the atomistic (very small) up to full-scale devices.
Manipulation, detection and use of light through excitonic materials are key concepts that will enable a raft of future technologies.
The risk of terror attacks and the use of fumigants within agriculture and pest control has prompted scientists to develop smart materials to detect chemical warfare agents and other harmful compounds. The field of sensors for these materials encompasses simple paper-based test strips for liquid chemicals through to large high-tech instruments. We’re working with Defence Science and Technology Group (DSTG) and CSIRO to develop portable, robust and rapid chemical sensors with high sensitivity and specificity that use the fluorescent qualities of nanocrystals to warn us about the presence of dangerous substances.
Australia leads the way in banknote technology. But with improved access to lower cost technologies, more sophisticated forgeries have been discovered. To maintain confidence in our currency, new security features are needed. The most difficult of these must be visible to the public or cash handler, who can use them to quickly determine whether the note is genuine. They must be robust, printable, and difficult to replicate. Together with Reserve Bank of Australia, we’re developing new optical security features that are difficult to copy and easy to verify. Using magnetic or infrared-active nanomaterials, they will be cost effective, durable and printable.
Achieving a truly sustainable future isn’t just about better renewable energy devices. It’s also about energy efficiency in existing technology. We’re working to produce future lighting and display technology, like LEDs and the screens in smartphones and computers that will offer superior efficiency, brightness and stability. While this work will lead to more energy efficient homes and workplaces, it could also help to advance the emerging field of polariton lasing, a relatively new variation on existing technology which has important applications in fields like information transfer and medical diagnosis.