Additive Engineering for Efficient and Stable MAPbI₃-Perovskite Solar Cells with an Efficiency of over 21

Area of Science:

• Materials Science
• Renewable Energy
• Photovoltaics

Background:

• High defect density in methylammonium lead iodide (MAPbI3) perovskite films causes significant carrier recombination losses, limiting perovskite solar cell (PSC) performance.
• Defects lead to nonradiative recombination, reducing charge carrier lifetime and overall device efficiency.

Purpose of the Study:

• To investigate the use of methylamine cyanate (MAOCN) as an additive to optimize the crystallization of MAPbI3 perovskite films.
• To improve the crystal quality, reduce defect density, and enhance the stability of MAPbI3-based PSCs.

Main Methods:

• Introduction of methylamine cyanate (MAOCN) molecules into MAPbI3 precursor solutions.
• Analysis of the effect of MAOCN on the solvent volatilization rate and crystallization process.
• Characterization of the crystal quality, defect density, carrier lifetime, and surface hydrophobicity of the resulting MAPbI3 films.

Main Results:

• MAOCN slowed solvent volatilization and delayed crystallization, leading to optimized MAPbI3 film quality without additive residue.
• MAOCN-treated films exhibited lower defect density and longer carrier lifetimes, significantly reducing recombination losses.
• MAOCN-based PSCs achieved a high power conversion efficiency of 21.28% and demonstrated improved stability, with efficiency dropping only ~5% after 30 days of storage.

Conclusions:

• Methylamine cyanate is an effective additive for improving the quality and performance of MAPbI3 perovskite films.
• The use of MAOCN enhances carrier dynamics and film stability, paving the way for more efficient and durable perovskite solar cells.