Research teams from Australian National University (ANU) and China are closing in on a solar cell design that could revolutionize solar panel efficiency.
For the past several years, engineers have been focusing on newer materials to build panels that are ultimately more efficient and cost-effective in tandem with silicon-based panels, which are popular and durable. Silicon-based photovoltaic (PV) panels currently have efficiency rates of 16% to 18% absorption, and researchers put the theoretical limit for silicon PV efficiency at 29%. Thomas White, a researcher, and professor at ANU and others note that innovation should be geared to improving energy conversion efficiency—the degree to which a panel converts energy from sunlight directly into electricity. “There’s a lot of emphases now on improving efficiency, and that’s why there’s suddenly these tandem approaches,” said White.
The breakthrough is the material perovskite, a crystalline structure first found in Russia in the mid-1800s. Studies suggest a perovskite solar panel could achieve efficiencies as high as 35%, while also reducing costs by cutting out some manufacturing process steps. The material is also much easier to fabricate and use than very high purity silicon, requiring an intricate refinement process. Perovskite is obtained as a powder mixed into a solvent and used to coat glass substrates.
In related developments, the Australian Renewable Energy Agency (ARENA) has announced more funding and support towards advanced solar photovoltaic energy applications, including a $15 million grant for R&D teams. The largest obstacle remains durability; perovskite crystals break down faster than silicon. The crystals dissolve easily so they are particularly susceptible to moisture and Perovskite also can’t take the heat as well as silicon can. White at ANU acknowledged this deficiency.
“The main challenge at the moment is stability,” he said. “We’re still struggling to make them sufficiently stable that you would want to put them on a rooftop for 25 years. So that’s still an unsolved question.”
Engineers based at universities in China and the United States have taken an interest in the state of perovskite solar cell research and in a recent edition of the scientific journal Advanced Functional Materials, published a paper acknowledging the problems with heightening stability but also thought there was “astounding progress in the efficiency of perovskite solar cells.” White agreed. “That will make or break perovskite over the next few years,” he said.