Co-author Shen Heping, who develops perovskite cells, shows a part of the cell in the lab of Australian National University (ANU) in Canberra, Australia, July 15, 2020. Researchers at the ANU recently said that they had achieved "a new efficiency record" for hydrogen cells that can convert water into hydrogen simply using sunlight. (By courtesy of Shen Heping/Handout via Xinhua)

 Researchers at the Australian National University (ANU) recently said that they had achieved "a new efficiency record" for hydrogen cells that can convert water into hydrogen simply using sunlight.

The research team said in a statement on ANU website on Monday that previous methods of converting water to hydrogen had a low overall energy conversion efficiency but the research has improved this.

The approach outlined in the ANU study used inexpensive semiconductor materials and resulted in a 17.6 percent solar-to-hydrogen efficiency, according to the researchers.

"This is nearing the efficiency of solar panels being installed on rooftops, which have an efficiency of around 20 percent," said the statement.

Lead author Siva Karuturi said that they are working towards reaching an efficiency of 20 percent in the coming months, which "will pave way for low-cost green hydrogen production."

"To produce hydrogen in the past, solar plants had to produce electricity which is then used to electrolyse water to produce hydrogen. This new method is more direct, making it more efficient," he said.

The research team said they used a "tandem" light absorber structure - placing a perovskite cell on top of a specially-made Si electrode.

Co-author Shen Heping, who develops perovskite cells, said that "with extraordinary optoelectronic properties," the perovskite materials offer "great potential for low-cost, high-efficiency tandem devices with Si."

"Together with unprecedented progress in efficiency, the perovskite material has also undergone significant improvement for its stability, making it one of the most attractive candidates for the solar industry," Shen said.

According to the researchers, this new method makes use of noble-metal catalysts such as platinum, and Karuturi said that they are working to replace them with cheap materials to further reduce costs in the future.