Heterogeneous Supersaturation in Mixed Perovskites

Area of Science:

• Materials Science
• Renewable Energy
• Solid-State Physics

Background:

• Hybrid lead halide perovskite solar cells show high power conversion efficiencies, nearing crystalline silicon.
• The role of twin defect sites as charge traps in perovskites is not fully understood.
• Investigating defect origins is crucial for optimizing perovskite photovoltaic performance.

Purpose of the Study:

• To investigate the origin and impact of twin defect sites in perovskite solar cells.
• To correlate twin defect formation with processing parameters like antisolvent addition.
• To understand how twin defects influence the performance of high-efficiency perovskite photovoltaics.

Main Methods:

• Transmission electron microscopy (TEM) was used to observe twin defects.
• X-ray diffraction (XRD) was employed to analyze crystal structure and defects.
• Correlation analysis was performed between antisolvent quantity and twin defect density.

Main Results:

• Twin defects were observed and their presence was found to correlate with the amount of antisolvent used during perovskite fabrication.
• The highest-performing perovskite solar cells exhibited suppressed twin defect densities.
• Heterogeneous supersaturation nucleation is proposed as a mechanism contributing to efficient device performance.

Conclusions:

• Antisolvent processing influences the formation of twin defects in perovskite films.
• Minimizing twin defects is critical for achieving high power conversion efficiencies in perovskite solar cells.
• Understanding nucleation processes can lead to improved perovskite-based optoelectronic devices.