Dual-Site Synergistic Regulation Enabled Interface Passivation and Strain Release Toward Efficient Perovskite Solar...

Area of Science:

• Materials Science
• Renewable Energy
• Optoelectronics

Background:

• Perovskite solar cells (PSCs) show high photovoltaic conversion efficiency (PCE) but are limited by interface defects and strain.
• Improving PCE and stability requires effective interface engineering in PSCs.

Purpose of the Study:

• To develop novel buried interface modifiers for PSCs to enhance PCE and stability.
• To investigate the role of benzyl phosphoric acids in defect passivation and strain regulation.

Main Methods:

• Assembly of brominated benzyl phosphate (4-BrBPA) and methoxy-substituted benzyl phosphate (4-MeOBPA) as interface modifiers between hole transport layers and perovskite.
• Characterization of interface properties, including energy level alignment, carrier extraction, and defect passivation.
• Fabrication and testing of PSCs with modified interfaces, including large-area devices and mini-modules.

Main Results:

• 4-BrBPA aligned with the hole transport layer, promoting energy level alignment and carrier transport.
• 4-BrBPA effectively passivated interfacial defects and released strain by chelating uncoordinated Pb2+ and vacancy I-.
• PSCs with 4-BrBPA achieved a champion PCE of 26.62% (certified 26.22%).
• The strategy was successfully extended to wide-bandgap, large-area PSCs, and mini-modules, achieving PCEs of 21.64%, 24.43%, and 21.08%, respectively.
• Optimized PSCs exhibited excellent operational and storage stability.

Conclusions:

• Benzyl phosphoric acids, particularly 4-BrBPA, are effective buried interface modifiers for PSCs.
• This approach significantly enhances PCE and stability by addressing interface defects and strain.
• The findings offer a promising strategy for advancing perovskite solar cell technology.