Eliminating Buried Interface Voids for High-Efficiency and Stable Perovskite Solar Cells

Area of Science:

• Materials Science
• Renewable Energy
• Chemical Engineering

Background:

• Solution-processible perovskite solar cells (PSCs) offer low-cost, large-scale production potential.
• Inefficient removal of dimethyl sulfoxide (DMSO) during annealing creates voids, degrading film quality, especially in large modules.
• Trapped DMSO and subsequent void formation at the buried interface are critical challenges for PSC performance and stability.

Purpose of the Study:

• To develop an interface engineering strategy to mitigate void formation at the buried interface in PSCs.
• To enhance the removal of residual DMSO from perovskite precursor films.
• To improve the efficiency and long-term stability of perovskite solar cells and modules.

Main Methods:

• Introduction of bridging molecules, specifically 1,10-Phenanthroline-4,7-dicarboxylic acid (PDA) and 1,10-Phenanthroline-4-carboxylic acid (PCA), at the perovskite buried interface.
• Utilizing the chelating properties of the 1,10-phenanthroline group in PDA and PCA to bind Pb²⁺ ions.
• Facilitating DMSO evaporation through enhanced Pb²⁺ chelation to minimize void formation.

Main Results:

• Bridging molecules effectively reduced voids at the buried interface by facilitating DMSO evaporation.
• Small-area perovskite solar cells achieved a power conversion efficiency (PCE) of 25.15%.
• Large-area mini-modules demonstrated a PCE of 21.15%, with unencapsulated modules retaining over 80% efficiency after 1,500 hours in ambient air.

Conclusions:

• Interface engineering with PDA and PCA is a viable strategy to improve perovskite film quality and device performance.
• The developed method significantly enhances the stability and efficiency of perovskite solar cells and modules under ambient conditions.
• This approach addresses key challenges in scaling up perovskite solar technology for commercial applications.