Scientists find green way to recycle toxic perovskite solar cells

Background on Perovskite Solar Cells

• Perovskite PVs are a promising alternative to silicon-based solar panels due to:
  • High efficiency in converting sunlight to electricity.
  • Lower production costs.
• Challenges:
  • Contain toxic lead.
  • Have a shorter lifespan than silicon cells.
  • Previous recycling methods relied on toxic organic solvents (e.g., dimethylformamide), posing environmental risks.

Relevance : GS 3(Science and Technology)

New Breakthrough: Water-Based Green Recycling Method

• Published in Nature, the study demonstrates:
  • A water-based solution for recycling perovskite layers.
  • Achieves almost same efficiency as fresh materials, even after 5 recycling cycles.
  • ~99% recovery of the solar cell layers after multiple rounds.

Key Components of the New Recycling Process

1. Sodium Acetate:
   1. Binds with lead ions → forms water-soluble lead acetate.
   2. Facilitates efficient dissolution of lead-based perovskite in water.

• Sodium Iodide:
  • Supplies iodide ions to restore degraded perovskite crystals.
  • Supports reformation of high-quality crystals during cooling.
• Hypophosphorous Acid:
  • Acts as a stabiliser to keep the water-based solution viable for multiple reuse cycles.

Recycling of Entire Solar Cell

• Used ethanol and ethyl acetate to dissolve and recover other cell layers.
• Successfully reassembled solar cells layer-by-layer with minimal loss.
• Achieved comparable efficiency to virgin cells, even after 5 reuse cycles.

Significance & Environmental Impact

• Addresses twomajor problems:
  • Toxicity due to lead.
  • Waste generation from short-lived solar cells.
• Promotes circular economy: keeping materials in use longer, reducing waste and emissions.
• Avoids toxic organic solvents, aligning with green chemistry principles.
• Supports low-cost, high-efficiency solar tech with significantly reduced lifecycle environmental burden.

Future Implications

• If scalable, it could:
  • Solve critical barriers to commercialisation of perovskite PVs.
  • Reduce environmental footprint of solar power generation.
• Need for life cycle assessment (LCA):
  • Evaluate overall environmental impact across production, use, and disposal phases.
  • Ensure no unintended ecological consequences.

Expert Commentary

• Researchers laud the breakthrough as a holistic shift from just lead recovery to full cell regeneration.
• It represents a mature approach to sustainability in renewable tech.
• Could pave the way for perovskite PVs to fulfill their promise as a key player in future clean energy systems.