UQ researchers create lead-free indoor solar panels

Chemical engineers at the University of Queensland have developed a fabrication method that eliminates the need for toxic lead and other hazardous solvents in indoor perovskite solar panels.

Indoor perovskite solar cells operate under low-intensity artificial light, such as light-emitting diodes (LEDs) and fluorescent lamps.

“Indoor solar cells themselves are not new, but the power conversion efficiency of the commercial silicon-based technology is only around 10%,” said Dr Miaoqiang Lyu, who led the research team with Professor Lianzhou Wang.

“Halide perovskites are an emerging technology that could replace silicon, offering much higher efficiencies and commercial potential,” Lyu explained. “However, most still rely on lead-based hazardous materials.

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

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

UQ researchers Dr Miaoqiang Lyu and Professor Lianzhou Wang. Image credit: The University of Queensland

Using the new method, the panels achieved an efficiency of 16.36% — 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.”

One application of the lead-free cells is 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.

The technology could also be used in trials of battery-powered electronic shelf labels at supermarkets, replacing thousands of paper price tickets and reducing manual labour.

“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 and scalable; they can be made on flexible plastic and in different shapes, making them easy to integrate into a wide 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 has been published in in ACS Energy Letters.

Top image credit: The University of Queensland