Toughened self-assembled monolayers for durable perovskite solar cells

Area of Science:

• Materials Science
• Renewable Energy
• Nanotechnology

Background:

• Hole-selective self-assembled monolayers (SAMs) are crucial for high-efficiency inverted perovskite solar cells (PSCs).
• Instability of conventional SAMs limits the operational performance and practical application of PSCs.
• Degradation of SAMs under operational stress leads to device failure and reduced power conversion efficiency (PCE).

Purpose of the Study:

• To enhance the conformational stability of hole-selective SAMs against external stresses.
• To suppress defect and void formation during SAM self-assembly.
• To improve the long-term operational stability and PCE of perovskite solar cells.

Main Methods:

• Employing a cross-linkable co-SAM strategy using azide-containing SAMs.
• Thermally activating the SAM to form a cross-linked, densely assembled co-SAM.
• Investigating SAM degradation mechanisms and their impact on perovskite stability.

Main Results:

• Achieved a certified PCE of 26.92% for the best-performing perovskite solar cell.
• Demonstrated excellent thermal stability with negligible decay at 85°C for 1,000 hours.
• Retained over 98% of initial PCE after 700 thermal cycles (-40°C to 85°C).

Conclusions:

• Cross-linkable co-SAMs significantly enhance the stability and durability of perovskite solar cells.
• This approach effectively minimizes substrate surface exposure and prevents perovskite decomposition.
• Provides a pathway for designing robust buried interfaces for highly efficient and durable perovskite solar cells on rough substrates.