Perovskite solar cells are among the most promising photovoltaic technologies due to power conversion efficiencies exceeding 25% and low manufacturing costs. One impediment to their commercialization is the environmental risk posed by the release of lead if a perovskite panel is damaged. This potential is addressed with a materials solution devised by researchers from Northern Illinois University and U.S. National Renewable Energy Laboratory to collect and retain the metal in such situations.

Lead leakage can be countered with a Scotch-tape-like film applied to the solar cells. PSCs and capture 99.9% of leaked lead in the event of solar cell damage. The industry-ready film can alleviate health and safety concerns without undermining perovskite solar cell performance or operation. A perovskite solar cell encapsulated with a transparent lead-absorbent film. Source: Xun Li, Northern Illinois UniversityA perovskite solar cell encapsulated with a transparent lead-absorbent film. Source: Xun Li, Northern Illinois University

The transparent tapes described in Nature Sustainability use lead absorbents made with a standard solar ethylene vinyl acetate film and a pre-laminated layer of lead-absorbing material. The tape can be attached to both sides of fabricated solar cells, as in the standard encapsulation process used to manufacture silicon-based photovoltaics.

The researchers put the tape through some harsh tests to gauge its durability: film-encapsulated perovskite cells were exposed to outdoor, rooftop conditions for three months. Additionally, the devices were damaged with razor blades and hammers prior to being submerged in water for seven days. The tapes demonstrated a lead-sequestration efficiency of over 99.9%.

“Our practical approach mitigates the potential lead-leakage to a level safer than the standard for drinking water,” said Northern Illinois University chemistry professor Tao Xu. “We can easily apply our lead-absorbing materials to off-the-shelf films currently used to encapsulate silicon-based solar cells at the end of their production, so existing fabrication processes for perovskite solar cells would not be disrupted. At the end of perovskite solar cell production, the films would be laminated to the solar cell.”

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