Efficient and Stable Inverted Perovskite Solar Cells Via a Multi-Arm Donor-Acceptor Dipole Molecular Bridge

Area of Science:

• Materials Science
• Photovoltaics
• Organic Chemistry

Background:

• Self-assembled monolayers (SAMs) advance perovskite solar cells (PSCs).
• Interfacial defects and strain limit PSC efficiency and stability.
• Novel molecular strategies are needed for interface optimization.

Purpose of the Study:

• To develop a multi-arm donor-acceptor (D-A) dipole molecular bridge strategy.
• To investigate the role of molecular-arm engineering in interface regulation.
• To enhance the performance and stability of p-i-n PSCs.

Main Methods:

• Design and synthesis of two D-A dipole molecules (N4IA and T4IA).
• Comparative analysis of N4IA and T4IA based on molecular structure and dipole moment.
• Fabrication and characterization of p-i-n PSCs using T4IA for interfacial modification.

Main Results:

• T4IA exhibits a larger molecular dipole and enhanced hole-transport properties compared to N4IA.
• T4IA optimizes energy-level alignment, accelerates charge extraction, and suppresses recombination.
• T4IA effectively passivates Pb²⁺ defects, reduces lattice strain, and improves interfacial stability.
• Optimized PSCs achieve a power conversion efficiency (PCE) of 26.79% with improved operational and thermal stability.

Conclusions:

• The multi-arm D-A dipole molecular bridge strategy is effective for buried-interface regulation in PSCs.
• T4IA demonstrates superior performance in enhancing energy-level alignment, charge transport, and interfacial stability.
• This approach offers a viable route for developing highly efficient and stable perovskite photovoltaic devices.