SnO₂ Interacted with Sodium Thiosulfate for Perovskite Solar Cells over 25% Efficiency

Area of Science:

• Materials Science
• Renewable Energy
• Nanotechnology

Background:

• Tin oxide (SnO2) is a key electron transport layer (ETL) in perovskite solar cells.
• SnO2 films often contain defects like oxygen vacancies and hydroxyl groups, hindering device performance.
• These defects cause charge recombination and limit overall solar cell efficiency.

Purpose of the Study:

• To improve the performance of SnO2 ETLs in perovskite solar cells.
• To reduce defects within SnO2 films using inorganic modification.
• To enhance charge carrier transport and extraction at the perovskite/SnO2 interface.

Main Methods:

• Bulk blending of SnO2 nanoparticles with inorganic sodium thiosulfate (Na2S2O3).
• Characterization of chemical state changes and film properties.
• Fabrication and testing of perovskite solar cells using modified SnO2 ETLs.

Main Results:

• Sodium thiosulfate strongly interacted with SnO2, altering its elemental chemical state.
• The modified SnO2 film exhibited improved uniformity, conductivity, and energy level alignment with perovskite.
• Perovskite crystallization was promoted, and trap density at the interface was reduced.
• The SnO2-modified perovskite solar cell achieved a champion power conversion efficiency of 25.2%.

Conclusions:

• Inorganic sodium thiosulfate effectively passivates defects in SnO2 ETLs.
• Sulfur-containing molecules offer a promising strategy for optimizing SnO2 properties in perovskite solar cells.
• The enhanced charge transport and reduced recombination lead to high-efficiency solar devices.