Mitigating Surface Defects in Tin-Based Perovskite Films with α-Tocopherol for Enhanced Photovoltaic Performance

Area of Science:

• Materials Science
• Renewable Energy
• Photovoltaics

Background:

• Surface defects in tin-based perovskite films are a major cause of degradation in perovskite solar cells (PSCs).
• These defects increase susceptibility to environmental factors like water and oxygen, leading to bulk defects and compromised performance.
• Addressing surface defects is crucial for improving the stability and efficiency of PSCs.

Purpose of the Study:

• To investigate the use of α-Tocopherol (vitamin E) as a passivation agent for tin-based perovskite films.
• To understand the mechanism by which α-Tocopherol interacts with the perovskite structure.
• To evaluate the impact of α-Tocopherol passivation on the performance and stability of tin-based PSCs.

Main Methods:

• Introduction of α-Tocopherol into tin-based perovskite films.
• Analysis of α-Tocopherol's interaction with perovskite components using experimental techniques.
• Density functional theory (DFT) calculations to study defect inhibition.
• Performance and stability testing of passivated tin-based PSCs.

Main Results:

• α-Tocopherol forms van der Waals and hydrogen bonds with perovskite components without entering the lattice.
• Passivation effectively suppresses both surface and interior oxidation of the perovskite films.
• DFT analysis confirms the inhibition of detrimental I─Sn antisite and Sn interstitial defects.
• Power conversion efficiency (PCE) increased from 9.19% to 13.14%, and device lifetime exceeded 50 days.

Conclusions:

• α-Tocopherol is an effective passivation agent for tin-based perovskite films.
• The mechanism involves surface interaction and suppression of oxidation and defect formation.
• This approach significantly enhances the efficiency and long-term stability of tin-based PSCs.