Molecular Design-Driven Interface Engineering Enabling Simultaneous Defect Passivation and Enhanced Hole Extraction...

Area of Science:

• Materials Science
• Renewable Energy
• Photovoltaics

Background:

• Interface engineering is crucial for addressing defects and energy level misalignment in perovskite solar cells.
• The perovskite/hole transport layer (HTL) interface is a key area for optimization.

Purpose of the Study:

• To design and synthesize novel multifunctional hole interface molecules (HTIMs) for perovskite solar cells.
• To investigate the impact of these HTIMs on interface defect passivation, energy level alignment, and carrier extraction.
• To evaluate the performance and stability of perovskite solar cells incorporating the optimized HTIMs.

Main Methods:

• Design and synthesis of three novel HTIMs with distinct substituents.
• Integration of HTIMs at the perovskite/HTL interface, specifically with Spiro-OMeTAD.
• Characterization of interface properties, including defect density and energy level alignment.
• Fabrication and testing of perovskite solar cell devices to determine power conversion efficiency (PCE) and operational stability.

Main Results:

• The HTIM MeS-TPA-Cbz-HAI demonstrated superior interface passivation and chemical compatibility with Spiro-OMeTAD.
• Devices incorporating MeS-TPA-Cbz-HAI achieved a PCE of 25.83%.
• Unencapsulated devices retained 94% of their initial efficiency after 1000 hours of operation under ambient conditions, showing excellent stability.

Conclusions:

• Novel HTIMs effectively passivate defects and improve energy level alignment at the perovskite/HTL interface.
• The MeS-TPA-Cbz-HAI molecule offers a promising strategy for enhancing both efficiency and long-term stability in perovskite solar cells.
• This interface engineering approach paves the way for more robust and efficient perovskite photovoltaic technologies.