The main environmental risks associated with lead in perovskite solar cells (PSCs) stem from the potential release and leakage of lead ions into the environment. Here are the key points detailing these risks:
Lead Leakage and Toxicity
- Lead Ion Leaching: The perovskite materials used in high-performance PSCs often contain lead in forms that are water-soluble, such as lead iodide. When a PSC is damaged, exposed to water (e.g., rain), or disposed of improperly, lead ions can leach out into soil and water sources, posing contamination risks.
- Environmental Contamination: The released lead increases concentration in soil and groundwater. For example, lead from a broken PSC module could raise lead levels in the topsoil by approximately 70 ppm, which is significant compared to natural soil lead levels that range from 30 to 200 ppm. This contamination poses risks to ecosystems and biodiversity.
- Health Hazards: Lead is highly toxic and is linked to severe health issues, including intellectual disabilities and other chronic conditions. The form of lead ions escaping from PSCs is particularly concerning due to their bioavailability and toxicity.
Specific Environmental Risks
- Water Quality: Lead contamination threatens groundwater and surface water quality, potentially affecting drinking water sources and aquatic life.
- Soil Contamination: Accumulation of lead in soils can adversely impact soil microorganisms, plants, and animals, entering the food chain and causing broader ecological harm.
- Air Quality and Fire Risks: There is also concern that fires involving PSCs could release lead compounds into the air, further spreading contamination, although water leaching is considered a more significant pathway.
Mitigation and Management Strategies
- Lead Sequestration Layers: Incorporating materials that capture or immobilize lead in the solar cell structure can reduce lead leaching when modules break.
- Encapsulation and Recycling: Proper encapsulation of PSCs and development of recycling programs are crucial to prevent environmental release of lead at end-of-life stages.
- Use of Phosphate Salts: Recent research has demonstrated that adding transparent phosphate salts to PSCs creates water-insoluble lead phosphates upon contact with water, effectively preventing lead from leaching into the environment and allowing for lead recovery.
- Alternative Lead-Free Perovskites: Although lead-free PSCs are being researched, they currently lack the performance and stability of lead-based versions, making lead management the preferred approach at present.
In summary, the primary environmental risk of lead in perovskite solar cells is the leakage of soluble lead ions into soil and water, which poses significant toxicity hazards to both ecosystems and human health. Addressing these risks involves improving module design for lead containment, implementing recycling schemes, and employing chemical additives like phosphate salts to immobilize lead in case of damage.
Original article by NenPower, If reposted, please credit the source: https://nenpower.com/blog/what-are-the-main-environmental-risks-associated-with-lead-in-perovskite-solar-cells/
