Buried Interface Modification Toward Efficient CsPbI_2.2Br_0.8 Based Monolithic Perovskite/Organic Tandem Solar Cells

Area of Science:

• Materials Science
• Renewable Energy
• Solid-State Physics

Background:

• Wide-bandgap perovskite sub-cells (WPSCs) are critical for perovskite-based tandem solar cells (PTSCs) but suffer from low efficiency due to crystallization issues.
• All-inorganic WPSCs (AIWPSCs) face performance limitations from nonradiative recombination caused by buried interface defects.

Purpose of the Study:

• To enhance the performance of all-inorganic wide-bandgap perovskite sub-cells (AIWPSCs).
• To improve the efficiency of perovskite/organic tandem solar cells (AIPOTSCs).

Main Methods:

• Introduction of methylamine propionate (MAPA), a propionate group-based ionic liquid, at the perovskite/electron-transport layer (ETL) interface.
• Passivation of buried interface defects in AIWPSCs through interaction between propionate anions and Pb-Pb dimers.
• Integration of optimized AIWPSCs with small-bandgap organic solar cells (SOSCs) to form tandem devices.

Main Results:

• MAPA effectively passivates interface defects, leading to more homogeneous perovskite film distribution.
• Achieved a high power conversion efficiency (PCE) of 18.29% and open-circuit voltage (V_OC) of 1.33 V for CsPbI_2.2Br_0.8-based AIWPSCs.
• Developed high-performance n-i-p structured all-inorganic perovskite/organic tandem solar cells (AIPOTSCs) with a PCE of 23.19% and V_OC of 2.08 V.

Conclusions:

• MAPA is a superior additive for optimizing AIWPSC performance by healing interface defects.
• The developed AIPOTSCs demonstrate significant potential for next-generation solar energy applications.