Sequential vacuum-evaporated perovskite solar cells with more than 24% efficiency

Area of Science:

• Materials Science
• Renewable Energy
• Photovoltaics

Background:

• Vacuum evaporation offers solvent-free, high-throughput fabrication for perovskite solar cells (PSCs).
• Current vacuum-evaporated PSCs exhibit lower power conversion efficiency (PCE) compared to solution-processed devices.
• Scalable production of efficient and stable PSCs remains a challenge.

Purpose of the Study:

• To develop an improved vacuum evaporation technique for high-performance PSCs.
• To address the efficiency gap between vacuum-evaporated and solution-processed PSCs.
• To demonstrate a reproducible method for large-area, stable perovskite optoelectronics.

Main Methods:

• Sequential vacuum evaporation utilizing a chlorine-containing alloy.
• Incorporation of the alloy to facilitate halide diffusion and perovskite formation.
• Fabrication and characterization of PSCs across various active areas.

Main Results:

• Achieved a maximum PCE of 24.42% for small-area PSCs.
• Demonstrated a certified PCE of 22.6% for a 1.0 cm² mini-module.
• Obtained 19.87% PCE for a 14.4 cm² mini-module.
• Unencapsulated PSCs maintained performance after over 4000 hours of storage in dry air.

Conclusions:

• The Cl-alloy-mediated sequential vacuum evaporation yields homogeneous, pinhole-free perovskite films with reduced defects.
• This method enables the scalable fabrication of high-efficiency, stable large-area PSCs.
• The approach is promising for various perovskite-based optoelectronic applications.