Solar sandwich tested
Australian scientists are working on new solar cell materials to replace silicon.
The current solar cell market is dominated by silicon-based technology, which is nearing its efficiency limit, so researchers are looking at other materials to build the next generation of cells.
Australian National University (ANU) engineers, in collaboration with researchers from the California Institute of Technology, have developed a way to combine silicon with perovskite to more efficiently convert sunlight into electricity.
The key is the way the materials are joined together to form what’s known as a ‘tandem solar cell’ – essentially one solar cell on top of another. The ANU researchers say theirs is one of the simplest ever developed.
“We have constructed a tandem structure that is unconventional. When engineers combine two cells they usually need to have an interlayer to allow electrical charge to be transferred easily between the two cells, so they can work together,” said ANU’s Dr Heping Shen.
Researcher Dr Daniel Jacobs says this is a bit like making a club sandwich with extra bread in the middle.
“We’ve found a new way to simply stack the two cells together so they’ll work efficiently with each other – we don’t need the interlayer, or extra bread, anymore,” Dr Jacobs said.
This minimises energy waste and simplifies the structure, hopefully making it cheaper and easier to produce.
“With tandems it’s crucial to demonstrate a fabrication process that is as simple as possible, otherwise the additional complexity is not worthwhile from a cost perspective”, Dr Jacobs said.
“Our structure involves one less fabrication step, and has benefits for performance too.”
Dr Jacobs says while it can be difficult to combine two materials in a tandem arrangement, once you get it right the efficiency goes up very quickly, well beyond what is possible with silicon by itself.
“We’ve already reached 24 per cent improvement in efficiency with this new structure, and there’s plenty of room left to grow that figure.”
Mayor Jamieson said the best way to do this was to restore the annual Financial Assistance Grants to councils to the equivalent of just one percent of total Commonwealth taxation revenue, a decision that would fit well with the Palaszczuk Government’s move to bring forward $100 million in Works for Queensland funding.
“The Financial Assistance Grants have historically been as high as two percent of Commonwealth taxation revenue, but in recent years their value has declined to approximately 0.55% of taxation revenue – all at a time when councils are expected to deliver more for their communities than has traditionally been the case,” Mayor Jamieson said.
“The State Government has seen the absolute win-win of using local governments as the mechanism to deliver essential community projects and infrastructure while boosting local jobs.
“For communities in drought, or those struggling with sluggish employment conditions, it is a guaranteed shot in the arm.
“With the funding of projects of this nature, you can keep economies ticking along, support the building industry and maintain jobs locally which in turn keeps communities productive as the projects make a real difference”.
Mayor Jamieson said local councils raised just 3 percent of all the taxation revenue in Australia but managed 33 percent of public assets.
“That shows how imbalanced the task is but also how effective we can be,” Mayor Jamieson said.
“The local government share of taxation revenue from Canberra has been declining over the past two decades.
“We need Canberra to return this money to local communities faster and in a way that better meets local needs and creates jobs,” he said.
Studies had confirmed that a lift in financial assistance grants to 1 percent of Commonwealth tax revenue would boost the nation’s GDP by more than $1.4 billion.