New method eliminates need for toxic lead in solar panels

A team of chemical engineers led by The University of Queensland’s Dr Miaoqiang Lyu and Professor Lianzhou Wang have developed a fabrication method that eliminates the need for toxic lead and other hazardous solvents in perovskite indoor solar panels.

“Indoor solar cells themselves are not new, but the power conversion efficiency of the commercial silicon-based technology is only around 10%,” Lyu said. “Halide perovskites are an emerging technology that could replace silicon, offering much higher efficiencies and commercial potential.

“However, most still rely on lead-based hazardous materials.

“The technology we developed eliminates those materials while still delivering high efficiency.”

UQ PhD student Zitong Wang, under the supervision of Lyu and Professor Wang, developed a safe and scalable vapour-based manufacturing process for fabricating high-quality lead-free perovskite material with fewer performance-limiting defects.

Indoor perovskite solar cells operate under low-intensity artificial light, such as LEDs and fluorescent lamps. Using the new method, the panels achieved an efficiency of 16.36% — which researchers say is the highest reported for this type of lead-free perovskite indoor solar cell made using an industry-compatible evaporation method.

“This material has very attractive properties that can absorb indoor light and convert very weak indoor light efficiently into electricity,” Lyu said. “By removing those solvents entirely, the process is much better suited to scalable manufacturing.”

Credit: The University of Queensland

Lead-free perovskite indoor solar cells are also increasingly viewed as an alternative to coin-cell and button batteries for low-power electronics like environmental sensors, wearables, medical and health monitoring devices, and small consumer electronics.

Supermarkets trialling battery-powered electronic shelf labels are among the potential early applications of the technology.

“With suitable voltage management, these devices can replace coin‑cell batteries, reducing the number of small batteries that end up as waste or in children’s toys,” Lyu said.

Panels fabricated using the UQ process are thin, scalable and can be made on flexible plastic and in different shapes, making them suitable to integrate into a range of products.

The next step is sealing the panels before further testing.

“I think the key here is encapsulation, to protect the material from oxygen and moisture,” Lyu said. “People will probably see perovskite indoor panels and integrated consumer electronics in the market in the next few years.”

The research paper is published in ACS Energy Letters.

Top image caption: UQ researchers Dr Miaoqiang Lyu and Professor Lianzhou Wang. Credit: The University of Queensland