UQ researchers set a new quantum dot solar record
Researchers at the University of Queensland say they have smashed the efficiency record for solar cells using the innovative ‘quantum dot’ approach, opening up the potential for commercially viable solar surfaces and greatly improved performance of solar panels in low-light environments.
The achievement has been published in the journal Nature Energy, and details how the Australian research team were able to achieve a 16.6 per cent conversion efficiency for the solar cells that use interactions between light and atoms at a quantum scale to produce electricity, smashing the previous record by 25 per cent.
That result matters because efficiency is one of the main barriers between promising laboratory technology and real-world solar products. Higher efficiency means more electricity can be generated from the same amount of light.
How quantum dot solar cells compare with silicon panels
It puts the efficiency of solar cells produced using the ‘quantum dot’ technique into a comparable range to that of conventional silicon solar cells, which have consistently achieved an efficiency in commercially available solar cells of above 20 per cent.
While the production of solar cells using silicon wafers has long been the industry standard, and represents the overwhelming majority of commercially available solar cells, quantum dot solar cells could unlock solar cells with much higher energy conversion efficiencies and have the potential to be incorporated into flexible materials.
For homeowners today, conventional silicon panels remain the proven commercial option. Quantum dot research is important because it points to what future solar products could become: lighter, more flexible and potentially useful in places where rigid panels are difficult to install.
Why printable and flexible solar matters
Professor Lianzhou Wang from the University of Queensland, who led the research, said that he was hopeful the innovative ‘quantum dot’ technology could be used in a range of new applications as it did not require the same rigid materials used in conventional solar cells.
“The new class of quantum dots the University has developed are flexible and printable,” professor Wang said.
“This opens up a huge range of potential applications, including the possibility to use it as a transparent skin to power cars, planes, homes and wearable technology.”
“Eventually it could play a major part in meeting the United Nations’ goal to increase the share of renewable energy in the global energy mix,” professor Wang added.
How quantum dot solar cells generate electricity
Quantum dot solar cells are part of a ‘next generation’ of solar energy innovations, that avoid the need for stiff and brittle silicon wafers, achieving the same light-to-electricity conversion characteristics in chemical-based semiconductors.
Electricity is produced by quantum dot solar cells when electrons are swapped between nanoparticles that have been exposed to sunlight.
As the quantum dot solar cells have the potential to generate electricity using almost any level of sunlight, they provide the potential for solar cells that can produce electricity even in low-light scenarios.
That low-light performance is one reason the technology is exciting. If it can be commercialised successfully, it could extend solar generation into surfaces and environments that are not ideal for traditional rooftop panels.
The commercialisation challenge
However, research into quantum dot solar cells is still in its early stages with researchers still examining how the innovative technology can be effectively deployed on a commercial scale and achieving the long-term performance that has already been achieved by conventional silicon cells.
In setting a new world record for quantum dot solar cell efficiency, the research team were able to overcome some of the challenges faced in making the solar cells stable, and the tendency for the quantum dot cells to form rough surfaces which hampered their ability to convert light to electricity.
By developing a new method of producing the quantum dot solar cells that reduced the ‘roughness’ of the cells, the University of Queensland research team were able to substantially improve their efficiency and accelerate progress towards the commercialisation of the technology.
“This new generation of quantum dots is compatible with more affordable and large-scale printable technologies,” Professor Wang said.
Why the efficiency jump matters
“The near 25 per cent improvement in efficiency we have achieved over the previous world record is important.”
“It is effectively the difference between quantum dot solar cell technology being an exciting ‘prospect’ and being commercially viable.”
The quantum dot solution is sensitive to light, and can be printed on to flexible cells and used to generate solar energy. The research was funded through a grant from the Australian Research Council, and the achievement of the Australian research team, who collaborated with researchers across the United Kingdom and China was praised by Vice-Chancellor of the University of Queensland professor Peter Høj.
What this could mean for future solar products
“The world needs to rapidly reduce carbon emissions and this requires us to invest much more in research to improve existing energy-generation technologies and develop entirely new ones,” Professor Høj said.
“Harnessing the power of fundamental technological and scientific research is a big part of this process – and that’s what we’re focused on at UQ.”
The integration of flexible solar cells into buildings and vehicles is the subject of research being undertaken by scientists and engineers at the University of Sydney, UNSW and Macquarie University, who have secured research funding and will co-operate in the development of fire-retardant solar cells used to produce ‘solar skin’ to coat surfaces.
For solar buyers, this does not replace today’s rooftop solar options. Instead, it shows how quickly solar technology is developing and why future solar may extend beyond conventional panels into windows, walls, vehicles and wearable devices.
Mazengarb, M 2015, 'Queensland researchers smash solar efficiency record for ‘quantum dot’ solar cells', RenewEconomy, 18 February, 2020.
