Bifunctional D-π-A Ligand Directs Self-Organized Interface Passivation for Efficient Perovskite Photovoltaics

Area of Science:

• Materials Science
• Renewable Energy
• Photovoltaics

Background:

• Passivation is crucial for perovskite solar cell (PSC) performance and stability.
• Current passivation methods are often depth-dependent, complicating fabrication and scalability.

Purpose of the Study:

• To develop a novel bifunctional passivating ligand for simultaneous bulk and interfacial defect passivation in PSCs.
• To investigate the self-organization behavior of the ligand within perovskite films.
• To demonstrate the impact of this ligand on PSC efficiency, stability, and scalability.

Main Methods:

• Synthesis and characterization of a bifunctional D-π-A ligand (triphenylamine-furan-cyanoacrylic acid, TPA-FCA).
• Incorporation of TPA-FCA into perovskite films during crystallization.
• Fabrication and testing of PSC devices with TPA-FCA passivation.
• Long-term operational stability testing under accelerated conditions.
• Fabrication and testing of large-area perovskite submodules.

Main Results:

• TPA-FCA self-organizes within perovskite films, vertically segregating to interfaces.
• Simultaneous passivation of bulk and interfacial defects was achieved.
• PSC devices achieved a champion efficiency of 26.56% (26.37% certified).
• Exceptional operational stability was demonstrated, with devices maintaining 90% efficiency after 1400 hours at 65 °C (T90 = 1400 h).
• Large-area perovskite submodules (30 cm × 30 cm) achieved a certified efficiency of 21.93%.

Conclusions:

• The bifunctional TPA-FCA ligand effectively passivates defects in PSCs, improving both efficiency and stability.
• The self-organization capability of TPA-FCA enables simultaneous bulk and interfacial defect passivation.
• This molecular design strategy is promising for the development of high-performance, stable, and scalable perovskite solar cells.