Oriented Molecular Bridge Constructs Homogeneous Buried Interface for Perovskite Solar Cells with Efficiency Over...

Area of Science:

• Materials Science
• Renewable Energy
• Photovoltaics

Background:

• Planar perovskite solar cells (PSCs) require optimized buried interfaces for improved efficiency.
• Molecular bridges are an effective strategy for interface engineering in PSCs.

Purpose of the Study:

• To construct and investigate the preferred arrangement of a 4-chloro-3-sulfamoylbenzoic acid (CSBA) molecular bridge at the buried interface of PSCs.
• To enhance the performance and stability of PSCs through interface modification.

Main Methods:

• Fabrication of PSCs utilizing a CSBA molecular bridge at the TiO2/perovskite interface.
• Systematic investigation of the CSBA molecular orientation and its interaction with TiO2 and perovskite layers.
• Performance characterization of small-area (0.08 cm2) and large-area (1 cm2) PSCs.
• Stability testing under ambient conditions and UV irradiation.

Main Results:

• CSBA molecules preferentially adsorb onto the TiO2 surface via COOH-Ti bonds and connect to perovskite via S═O-Pb bonds, forming an oriented molecular bridge.
• The oriented CSBA bridge passivates interfacial defects, optimizes energy levels, and relieves perovskite tensile stress.
• A certified power conversion efficiency (PCE) of 25.32% was achieved for 0.08 cm2 PSCs, the highest for TiO2-based planar PSCs.
• A champion PCE of 24.20% was achieved for 1 cm2 PSCs, demonstrating significant progress for large-area devices.
• Unencapsulated PSCs maintained approximately 91% and 85% of their initial PCE after 3000 hours of ambient aging and 1200 hours of UV exposure, respectively.

Conclusions:

• The oriented CSBA molecular bridge effectively enhances the efficiency and stability of planar PSCs.
• This interface engineering approach represents a significant advancement for both small- and large-area perovskite solar cell technology.
• The developed PSCs exhibit promising long-term operational stability.