Skip to content
Energy, Engineering

World-record photovoltaic efficiency achieved for kesterite solar cell

UNSW Sydney 4 mins read
  • Media:

Engineers at UNSW have broken the world record for a specific type of solar cell that has been touted as a potential long-term improvement in photovoltaic technology.

PV researchers around the world are working to find the best material to combine with traditional silicon cells to form a tandem solar cell, which can boost efficiency compared to single junction solar cell.

Scientia Professor Xiaojing Hao and her team from UNSW’s School of Photovoltaic and Renewable Energy Engineering have achieved a best-ever efficiency of 13.2% for high bandgap kesterite solar cells, which had been enhanced with hydrogen.

Kesterite is naturally occurring mineral but can also be artificially created at low cost by combining copper, zinc, tin and sulphur – which are not only all hugely abundant, but are also non-toxic.

The names of the component parts are why, in its synthesised form, kesterite is known as CZTS.

CZTS is a promising material for future generations of solar cells because it is environmentally friendly, cost-effective to manufacture, and is known to maintain its photovoltaic performance over a long period of time.

However, its efficiency has been long-hampered, largely by the number of defects created within CZTS during production, which are hard to avoid.

The UNSW team, including Dr Kaiwen Sun and Dr Jialiang Huang, say they have helped to solve this problem by annealing, or heat-treating, the CZTS solar cell device in a hydrogen-containing atmosphere.

The fundamental research behind the record-breaking efficiencies, which first achieved 11.4% after six years of stagnation for CZTS, has now been published in the Nature Energy journal.

“The big picture here is that we ultimately want to make electricity cheaper and greener to generate,” says Prof. Hao.

“Silicon modules have almost reached the limit of their theoretical efficiency, so what we are trying to do is answer the question coming from the PV industry as to what the next generation of cells will be made of.

“And as well as that, how can we make solar panels less expensive to manufacture, and how can we get more electricity per area so the panels can be particularly beneficial for area-limited PV applications?”

Passivation process

Prof. Hao says that her work on CZTS solar cells has been based on a bottom-to-top approach, whereby all the best attributes required have been taken into consideration first in order to try to identify the perfect material.

The maximum photovoltaic efficiency of CZTS had been stuck at 11% for the past six years, but Prof. Hao and her team’s introduction of hydrogen to help eliminate some of the defects during production now promises even more advancements.

“In basic terms, to create CZTS you take copper, tin, zinc and sulphur and ‘cook’ them all together at a certain temperature which turns it into a material you can use as a semiconductor,” she says.

“The tricky part is controlling the defects that are introduced during that process. What we have shown in this work is that introducing hydrogen can ensure those defects have less of an impact – which is known as passivation.

“Because hydrogen is modulating the defects within CZTS, that’s what helps increase its efficiency in terms of converting sunlight into electricity.”

The use of CZTS could be best implemented in what are known as tandem solar cells, which combine two or more solar cells to capture and convert more of the solar spectrum into electricity, improving overall efficiency.

Prof. Hao says she is hopeful the new breakthrough will accelerate the chances of CZTS reaching 15% efficiency within the next year, and expects its commercialisation by 2030.

“There is still work to be done to find ways to further reduce the defects we find in CZTS, either during the fabrication or via post-fabrication treatments,” she says.

“But we know that this is a good material. When we consider the requirements from the bottom up, we know that we need something that is widely abundant, that is environmentally friendly, that has good optoelectronic properties and can last a long time – and CZTS fits the bill.”

Other tandem options

Prof. Hao and her team at UNSW are also conducting extensive research into another potential material that could partner with silicon, perovskite.

Perovskite is more efficient (close to 27% in small-area examples) in converting the sun’s energy into electricity, but also degrades quickly and contains highly toxic components which can dissolve in water such as lead.

“When you go the other way, from the top to the bottom, maybe with something like perovskite, you can get really high performance and high efficiency at the beginning, but it’s much less stable and the panels might only last for one year so it’s not sustainable,” she says.

“It can take a long time to solve those problems, whereas with CZTS if we can get it to 20% efficiency then I think it will really take off because there are no other limitations since it meets all the criteria for the type of material we want to be using.

“Overall, I think we should be looking into all different types of materials for the top layer of tandem cells. That’s the only way we can maximise our chances of success and accelerate the speed towards obtaining highly efficient tandems that we can use long into the future.”


Key Facts:

UNSW researchers have set a new best mark for a kesterite (CZTS) solar cell which could be a long-term, sustainable and cost-effective add-on or replacement for silicon-based panels.


Contact details:

Neil Martin, News & Content Coordinator, UNSW Sydney.

Email: n.martin@unsw.edu.au

Media

Images
UNSW research team with the record-breaking kesterite solar cell. Pictured are Dr Jialiang Huang, Dr Kaiwen Sun, Scientia Professor Xiaojing Hao and Mr Ao Wang.nPhoto: UNSW SydneyUNSW research team with the record-breaking kesterite solar cell. Pictured are Dr Jialiang Huang, Dr Kaiwen Sun, Scientia Professor Xiaojing Hao and Mr Ao Wang.nPhoto: UNSW Sydney

UNSW Xiaojing Hao Team RLR_0761-3c1.jpg

UNSW research team with the record-breaking kesterite solar cell. Pictured are Dr Jialiang Huang, Dr Kaiwen Sun, Scientia Professor Xiaojing Hao and Mr Ao Wang.nPhoto: UNSW Sydney
Download media
The record-breaking kesterite solar cell developed at UNSW.nPhoto: UNSW SydneyThe record-breaking kesterite solar cell developed at UNSW.nPhoto: UNSW Sydney

IMG_0507.jpg

The record-breaking kesterite solar cell developed at UNSW.nPhoto: UNSW Sydney
Download media
The kesterite, or CZTS, solar cell developed at UNSW has reached a world record efficiency of 13.2%.nPhoto: UNSW SydneyThe kesterite, or CZTS, solar cell developed at UNSW has reached a world record efficiency of 13.2%.nPhoto: UNSW Sydney

IMG_0518.jpg

The kesterite, or CZTS, solar cell developed at UNSW has reached a world record efficiency of 13.2%.nPhoto: UNSW Sydney
Download media
Scientia Professor Xiaojing Hao working in the lab.nPhoto: UNSW SydneyScientia Professor Xiaojing Hao working in the lab.nPhoto: UNSW Sydney

XiaojingHaoLab.jpg

Scientia Professor Xiaojing Hao working in the lab.nPhoto: UNSW Sydney
Download media

More from this category

  • Engineering, Science
  • 17/02/2025
  • 11:00
UNSW Sydney

Researchers spin ‘wheel of fortune’ to land big prize: a fundamental proof of quantum mechanics

Researchers from the National University of Singapore (NUS) and University of New South Wales (UNSW) Sydney have proven fundamentally that a spinning atomic nucleus…

  • Contains:
  • Energy, Government Federal
  • 17/02/2025
  • 10:55
Australians for Affordable Energy

Taxpayers should not foot the bill for nuclear risk: Australians for Affordable Energy

If private insurers refuse to cover nuclear reactors the financial risks will be shifted onto Australian taxpayers, meaning we are still unclear how much taxpayers will have to cover of the nuclear bill. Australians for Affordable Energy has expressed deep concern over the revelation the private sector may not be able to insure nuclear reactors, following comments on Monday from the CEO of the Insurance Council of Australia. Many of Australia’s leading insurance companies won’t cover damage from a nuclear disaster, leaving the government as the insurer. By shifting the financial burden of insuring nuclear facilities onto taxpayers, Australians could…

  • Energy, Food Beverages
  • 17/02/2025
  • 08:00
Technofast Industries

Swiss HAELOK® technology boosts speed, safety, and sustainability of gastight HVAC and refrigeration connections without welding

Leaking refrigerant in commercial and industrial HVAC and refrigeration systems can be difficult to trace and remedy, particularly if the piping systems involved were…

  • Contains:

Media Outreach made fast, easy, simple.

Feature your press release on Medianet's News Hub every time you distribute with Medianet. Pay per release or save with a subscription.