Multiscale Characterization of Electrode-Induced Degradation in Perovskite Solar Cells

Area of Science:

• Materials Science
• Renewable Energy
• Solid-State Physics

Background:

• Metal-halide-perovskite (MHP) solar cells offer promising efficiency but suffer from stability issues hindering commercialization.
• Understanding degradation mechanisms is essential for improving the long-term performance and viability of MHP technologies.

Purpose of the Study:

• To investigate the degradation modes of MHP solar cells under dark storage conditions.
• To identify specific electrode corrosion pathways and their impact on device performance.
• To demonstrate effective mitigation strategies for enhancing MHP solar cell stability.

Main Methods:

• Multiscale characterization including current-voltage (JV) curves, electroluminescence (EL), and photoluminescence (PL) imaging.
• Cross-sectional Kelvin probe force microscopy (KPFM) to map nanoscale electric field properties.
• Electron microscopy (SEM/TEM) for structural and chemical analysis of degraded interfaces.

Main Results:

• Full devices degraded via silver (Ag) electrode diffusion into the absorber, forming AgI and impacting ETL/perovskite and perovskite/HTL interfaces.
• Devices without metal electrodes showed degradation via indium tin oxide (ITO) corrosion, creating voids and In/Sn diffusion into the absorber.
• Mitigation was achieved using a SnO_x blocking layer and replacing ITO with FTO (fluorine-doped tin oxide).

Conclusions:

• Metal electrode diffusion is the primary dark degradation pathway, but ITO corrosion and absorber instability also require attention.
• Interface engineering and material selection (e.g., FTO over ITO) are effective strategies to improve MHP solar cell stability.
• This work provides a multiscale understanding linking interface properties to device-level degradation and highlights pathways for enhanced MHP solar cell longevity.