Bifunctional Molecular Bridge with Tunable Dielectric Constant for Air-Processed Perovskite Solar Cells

Area of Science:

• Materials Science
• Renewable Energy
• Photovoltaics

Background:

• Current perovskite solar cell (PSC) research primarily focuses on chemical passivation of defects.
• The combined approach of chemical passivation and dielectric screening for enhanced PSC performance remains underexplored.

Purpose of the Study:

• To design and introduce novel bridging molecules, Ethanolamine sulfate (EAS) and Ethanolamine phosphate (EAP), for synergistic interface modification in air-processed PSCs.
• To investigate the impact of tunable dielectric constants and dual active sites on PSC performance and stability.

Main Methods:

• Synthesized EAS and EAP molecules with tunable dielectric constants.
• Applied EAS and EAP to the SnO2/perovskite interface in n-i-p structured PSCs under ambient conditions.
• Characterized the effects of molecular modification on defect passivation, crystallization kinetics, stress, carrier dynamics, power conversion efficiency (PCE), and operational stability.

Main Results:

• EAS and EAP molecules effectively passivated defects, regulated crystallization, alleviated stress, and improved carrier dynamics.
• EAP modification resulted in a champion PCE of 25.22% for air-processed n-i-p PSCs.
• Achieved exceptional stability: 95.0% PCE retention after 4392 hours of storage and 95% after 1000 hours of MPPT at 40°C.

Conclusions:

• Synergistic interface engineering using molecules like EAP offers a promising strategy for high-performance, stable air-processed PSCs.
• The dual functionality of EAS and EAP in defect passivation and dielectric screening is key to their effectiveness.
• This research provides a foundation for rational molecular design in interface engineering for next-generation solar cells.