Planar Perovskite Solar Cells with High Efficiency and Fill Factor Obtained Using Two-Step Growth Process

Area of Science:

• Materials Science
• Renewable Energy
• Photovoltaics

Background:

• Hybrid organic-inorganic perovskite solar cells (PSCs) are promising next-generation photovoltaics due to low-cost fabrication potential.
• Achieving superior photoactive perovskite layer quality is crucial for enhancing PSC performance.

Purpose of the Study:

• To develop a method for obtaining high-crystallinity, large-grain perovskite films.
• To demonstrate enhanced photovoltaic performance and stability in planar PSCs using this method.

Main Methods:

• Utilizing excess lead iodide (PbI2) in conjunction with the "solution-processed grain-growth promotion" (SSGP) technique.
• Fabrication of normal-architecture planar PSCs.

Main Results:

• Achieved perovskite films with high crystallinity and large grain size.
• Demonstrated PSCs with a record fill factor (FF) of 83.4% without compromising other parameters.
• Attained high power conversion efficiencies of 21.3% (forward) and 21.6% (reverse) with high FF.
• Showcased robust light-soaking and thermal stability for unencapsulated PSCs.
• Obtained high efficiency (20.1%) with negligible hysteresis on large active area (∼1 cm2) PSCs.

Conclusions:

• The SSGP technique effectively improves perovskite film quality, leading to superior PSC performance.
• Enhanced optical properties, carrier extraction, and reduced recombination losses contribute to high efficiency and stability.
• The developed PSCs exhibit promising potential for commercial applications due to their performance and durability.