Efficient Inverted Perovskite Solar Cells via Improved Sequential Deposition.

Area of Science:

• Materials Science
• Renewable Energy
• Photovoltaics

Background:

• Inverted-structure perovskite solar cells (PSCs) offer advantages like low-temperature processing and stability.
• The two-step sequential deposition method is favored for its ease of fabrication and repeatability.
• Achieving high power conversion efficiencies (PCEs) in inverted PSCs comparable to regular structures remains a challenge.

Purpose of the Study:

• To enhance the performance of inverted PSCs fabricated via a two-step sequential deposition method.
• To investigate the impact of a novel interface treatment on perovskite film quality and device efficiency.
• To achieve state-of-the-art PCEs and improved stability in inverted PSCs.

Main Methods:

• An improved two-step sequential deposition technique was developed.
• The bottom organic hole-selective layer was treated with a binary modulation system (polyelectrolyte and ammonium salt).
• This treatment aimed to refine perovskite film interfaces, reduce defect density, and improve charge transport.

Main Results:

• The optimized inverted PSCs achieved a record PCE of 23.4%, a significant increase from 18.1%.
• Open-circuit voltage (Voc) was enhanced by 100 mV due to improved film quality and reduced defects.
• The improved devices demonstrated good operational and thermal stability.

Conclusions:

• The novel interface treatment effectively enhances perovskite film quality and device performance in inverted PSCs.
• This strategy provides a pathway to achieving high-efficiency and stable inverted PSCs using the two-step sequential deposition method.
• The findings offer valuable insights into perovskite crystal growth and defect modulation for advanced solar cell applications.