Effective encapsulation techniques for perovskite-silicon tandem solar cells focus on material selection, stability enhancement, and compatibility with tandem architectures:
Encapsulant Materials
- Thermoplastic polyurethane (TPU) and thermoplastic polyolefin (TPO) are preferred over ethylene vinyl acetate (EVA) due to their lower hygroscopicity and thermal stability. TPU offers UV-blocking properties (cutoff at 400 nm) but reduces perovskite cell current in UV regions, while TPO maintains better UV transparency.
- Polyolefin elastomers (POE) in glass-glass lamination withstand IEC 61215 damp heat tests, retaining >95% efficiency after 10+ months outdoors.
Encapsulation Methods
- Glass-glass lamination with vacuum processing ensures minimal air trapping and mechanical stability. This method uses POE or TPO with edge sealing for perovskite-silicon tandems, passing IEC thermal cycling and damp heat tests.
- Thin-film encapsulation with materials like PMMA, PDMS, or parylene C provides moisture barriers but may require additional edge-sealing for tandems. Plasma-deposited inorganic layers (e.g., Al₂O₃ via ALD) enhance impermeability.
Stability Testing
- IEC 61215 protocols (damp heat at 85°C/85% RH; thermal cycling -40°C to 85°C) are critical for validating commercial viability. TPU/TPO-based minimodules show resilience in these tests, though UV absorption in TPU necessitates optimization for current matching.
- Outdoor testing confirms long-term durability, with POE-laminated devices maintaining full efficiency over 10+ months.
Critical Considerations
- Optical impact: Encapsulants with UV-blocking additives (e.g., TPU) require current-balancing adjustments between perovskite and silicon subcells.
- Thermomechanical properties: Low-modulus elastomers (~21 MPa) minimize stress from thermal expansion mismatches during cycling.
- Edge sealing with hermetic barriers (e.g., epoxy/glass frit) prevents moisture ingress, a common failure point.
For commercialization, glass-glass lamination with POE or TPO, combined with rigorous IEC testing, currently represents the most reliable approach.
Original article by NenPower, If reposted, please credit the source: https://nenpower.com/blog/what-are-the-most-effective-encapsulation-techniques-for-perovskite-silicon-tandem-solar-cells/
