Efficient and Stable Perovskite Solar Cell Achieved with Bifunctional Interfacial Layers.

Area of Science:

• Materials Science
• Renewable Energy
• Photovoltaics

Background:

• Controlling surface morphology and trap states in perovskite films is crucial for perovskite solar cell (PSC) performance and stability.
• Solution-processed perovskite films often suffer from surface defects and moisture sensitivity, limiting their commercial viability.

Purpose of the Study:

• To develop a new passivation strategy for enhancing the efficiency and moisture resistance of PSCs.
• To investigate the effect of a poly(triaryl amine) (PTAA) layer on perovskite film properties and device performance.

Main Methods:

• A thin layer of PTAA was spin-coated onto perovskite films before annealing.
• Surface morphology, trap states, charge recombination, and charge transfer dynamics were analyzed.
• Device efficiency and long-term stability under ambient conditions were evaluated.

Main Results:

• The PTAA treatment resulted in smooth, compact perovskite films with passivated surface defects and grain boundaries.
• PTAA treatment significantly reduced charge recombination and improved charge transfer, evidenced by time-resolved photoluminescence.
• PTAA-treated PSCs achieved an average efficiency of 17.77% (peak 18.75%) and retained 83% of initial efficiency after 1 month, compared to 56% for control cells.

Conclusions:

• PTAA acts as an effective passivation layer, improving both the efficiency and stability of PSCs.
• The developed method offers a promising approach for fabricating stable and high-performance perovskite solar cells.
• PTAA's hydrophobic nature provides excellent protection against moisture, a key challenge for PSCs.