Cascade Reaction in Organic Hole Transport Layer Enables Efficient Perovskite Solar Cells

Area of Science:

• Materials Science
• Photovoltaics
• Organic Electronics

Background:

• The hole transport layer (HTL) is critical for high-efficiency perovskite solar cells (PSCs).
• Traditional doping methods for HTLs are slow, environment-dependent, and can degrade perovskite layers.
• This limits the commercial viability and technological advancement of PSCs.

Purpose of the Study:

• To develop a novel, rapid, and environment-independent doping strategy for organic HTLs in PSCs.
• To mitigate the detrimental effects of additives like 4-tert-butylpyridine (tBP) on perovskite stability.
• To improve the overall efficiency and reproducibility of PSCs.

Main Methods:

• Introduction of a cascade reaction into Spiro-OMeTAD using iodobenzene diacetate as an initiator.
• In-situ generation of Spiro radicals and formation of a tBP-iodobenzene complex to prevent perovskite erosion.
• Testing the doped HTL in both Spiro-OMeTAD and PTAA-based PSC architectures.

Main Results:

• Achieved a champion power conversion efficiency (PCE) of 25.76% for Spiro-OMeTAD based PSCs (certified 25.38%).
• Demonstrated a PCE of 23.76% for PTAA-based PSCs, showcasing broad applicability.
• The new doping process is rapid, air-independent, and enhances PSC reproducibility.

Conclusions:

• The developed cascade reaction offers a superior alternative to traditional doping methods for organic HTLs.
• This strategy effectively enhances PSC performance and stability while simplifying the manufacturing process.
• The findings represent a significant step towards the commercialization of efficient and reliable perovskite solar cells.