Strengthening Substrate Anchoring of Polymeric Self-Assembled Monolayers for Efficient and Stable Inverted Perovskite...

Area of Science:

• Materials Science
• Renewable Energy
• Photovoltaics

Background:

• Small-molecule self-assembled monolayers (SAMs) are effective hole-transporting layers in perovskite solar cells (PSCs).
• Polymeric SAMs offer improved stability but often underperform due to underexplored molecular configurations.
• Steric hindrance in existing polymeric SAMs limits substrate coverage and anchoring.

Purpose of the Study:

• To design and synthesize a novel polymeric SAM with optimized molecular configuration for enhanced PSC performance.
• To investigate the impact of reduced steric hindrance on molecular ordering and substrate coverage.
• To improve the power conversion efficiency (PCE) and operational stability of PSCs.

Main Methods:

• Designed a new polymeric SAM, Poly-4PADCB, by selecting specific monomer linkage sites to minimize steric hindrance.
• Investigated the molecular configuration and substrate anchoring capability of Poly-4PADCB compared to previous polymers.
• Fabricated PSCs using Poly-4PADCB as the hole-transporting layer and evaluated their performance and stability.

Main Results:

• Poly-4PADCB exhibits unidirectional phosphate group alignment, leading to higher substrate coverage and improved molecular ordering.
• The ordered interface facilitates high-quality perovskite growth and optimizes energy level alignment.
• PSCs with Poly-4PADCB achieved a certified PCE of 26.50% and maintained 96% of initial performance after 2000 hours of testing.

Conclusions:

• Optimizing monomer linkage in polymeric SAMs significantly enhances their performance in PSCs.
• Poly-4PADCB provides a robust interfacial architecture that improves both efficiency and long-term stability.
• This work offers a promising strategy for developing next-generation high-performance and stable perovskite solar cells.