Atomistic Mechanism of Surface-Defect Passivation: Toward Stable and Efficient Perovskite Solar Cells

Area of Science:

• Materials Science
• Renewable Energy
• Computational Chemistry

Background:

• Perovskite solar cells (PSCs) require enhanced stability and defect passivation for long-term performance.
• Molecular engineering is a key strategy to address these challenges in PSCs.

Purpose of the Study:

• To investigate the passivation effects of bidentate molecules 2-MP and 2-MDEP on iodine vacancies in MAPbI3.
• To compare the efficacy of 2-MDEP and 2-MP in improving PSC stability and performance.

Main Methods:

• Density functional theory (DFT) calculations.
• Ab initio molecular dynamics (AIMD) simulations.
• Investigated passivation effects on MAPbI3 iodine vacancies.

Main Results:

• 2-MDEP demonstrated stronger adsorption and charge localization on Pb atoms due to better lattice matching.
• Both 2-MP and 2-MDEP improved activation barriers for ion migration.
• AIMD simulations confirmed enhanced structural stability and reduced nonradiative recombination.
• 2-MDEP exhibited superior moisture shielding due to durable Pb-heteroatom interactions and hydrophobicity.

Conclusions:

• 2-MDEP is a more effective passivation molecule than 2-MP for perovskite solar cells.
• The findings provide insights for designing advanced passivation molecules for efficient and stable PSCs.