Dual Modification Strategy of Ionic Liquid for Durable Perovskite Photovoltaics

Area of Science:

• Materials Science
• Renewable Energy
• Photovoltaics

Background:

• Perovskite solar cells (PSCs) show promise for high power conversion efficiency (PCE).
• Challenges remain in achieving uniform hole transport layers (SAMs) and minimizing perovskite film defects.
• Current PSCs with SAMs achieve PCEs over 27%, but performance is limited by non-uniformity and defects.

Purpose of the Study:

• To develop a dual modification strategy for enhancing SAM uniformity and passivating perovskite defects.
• To investigate the role of 1-butyl-3-methylimidazole-hexafluorophosphate (BM) in improving PSC performance.
• To achieve higher PCE and enhanced operational stability in inverted PSCs.

Main Methods:

• Incorporation of ionic liquid 1-butyl-3-methylimidazole-hexafluorophosphate (BM) into the perovskite precursor solution.
• Utilizing BM to occupy halide vacancies and passivate uncoordinated Pb2+.
• Regulating SAM uniformity and perovskite crystallization kinetics through BM's ionic properties and functional group interactions.

Main Results:

• BM incorporation led to enhanced SAM uniformity and reduced perovskite surface roughness.
• Passivation of defects and occupation of halide vacancies by BM.
• Formation of highly crystalline perovskite films with enlarged grain sizes and reduced defect density.
• Achieved a champion PCE of 26.59% for the dual-modified PSC.
• Demonstrated exceptional operational stability with no PCE degradation after 1000 hours of continuous MPP operation.

Conclusions:

• Synchronous modification of SAMs and perovskite using BM is an effective strategy for improving PSC performance.
• BM acts as a defect passivator and promotes uniform film formation, leading to higher PCE.
• The developed PSC exhibits excellent operational stability, paving the way for commercial viability.