Orthogonally Arranged Bimolecular Passivation: Sequential Interface Engineering Improves Charge Transfer at the...

Area of Science:

• Materials Science
• Renewable Energy
• Photovoltaics

Background:

• Surface passivation is crucial for increasing power conversion efficiency (PCE) in perovskite solar cells (PSCs).
• Nonradiative recombination and energy level misalignment at the perovskite/PCBM interface limit overall efficiency in p-i-n PSCs.

Purpose of the Study:

• To develop a sequential interface engineering (SIE) strategy to improve charge transfer at the perovskite/PCBM interface in inverted p-i-n PSCs.
• To reduce nonradiative recombination and enhance energy level alignment for higher PCE and stability.

Main Methods:

• Sequential interface engineering (SIE) using p-Anisidine-2-sulfonic acid (pAsA) for perovskite surface defect passivation.
• Introduction of ethylenediamine diiodide (EDAI2) at the perovskite/PCBM interface to form dipoles and further passivate defects.
• Theoretical calculations to validate the orthogonal bimolecular passivation approach.

Main Results:

• The SIE strategy effectively suppresses nonradiative recombination and optimizes interface morphology and energy level alignment.
• Achieved a remarkable PCE of 24.85% in MA-free inverted perovskite solar cells.
• Demonstrated significantly enhanced stability, retaining 84.92% of initial efficiency after 2000 hours of tracking.

Conclusions:

• The developed SIE strategy offers a synergistic passivation approach for advancing PSC performance.
• This method holds great potential for improving both the efficiency and long-term stability of perovskite solar cells.