Confining iodide migration with quantified barrier for durable perovskite solar cells

Area of Science:

• Materials Science
• Renewable Energy
• Photovoltaics

Background:

• Perovskite solar cells (PSCs) suffer from long-term instability due to iodide ion migration, which degrades charge transport and electrode layers.
• Current strategies using blocking layers are insufficient to completely prevent ion movement without compromising carrier transport.

Purpose of the Study:

• To quantify the energy barrier for iodide ion migration in PSCs.
• To develop a composite layer that effectively suppresses ion migration and enhances device stability.
• To improve hole extraction efficiency and overall device performance.

Main Methods:

• Quantification of the energy barrier for ion migration.
• Development of a composite layer utilizing scattering and drift effects.
• Incorporation of Poly(N-vinylcarbazole) as a high work function hole transport material.
• Device fabrication and performance testing under accelerated aging conditions.

Main Results:

• Iodide ion migration was reduced by 99.9% through the developed composite layer.
• A composite layer was engineered to meet the ion migration energy barrier threshold.
• The use of Poly(N-vinylcarbazole) addressed band shifts, enhancing hole extraction.
• The final device achieved a certified steady-state efficiency of 25.7%.

Conclusions:

• The novel composite layer effectively mitigates iodide ion migration, significantly improving perovskite solar cell stability.
• The optimized hole transport material and composite layer combination leads to enhanced device performance and longevity.
• The developed strategy offers a promising pathway for achieving highly stable and efficient perovskite solar cells.