Flexible p-i-n perovskite solar cell with optimized performance by KBF₄ additive

Area of Science:

• Materials Science
• Renewable Energy
• Solid-State Physics

Background:

• Flexible perovskite solar cells (F-PSCs) offer advantages like light weight and easy installation for clean energy applications.
• However, improving the power conversion efficiency (PCE) of F-PSCs remains a critical challenge, often limited by trap defects in perovskite films.

Purpose of the Study:

• To investigate the impact of perovskite trap defect density on the PCE of F-PSCs.
• To demonstrate the effectiveness of potassium tetrafluoroborate (KBF4) as a passivation agent for reducing trap defects and enhancing F-PSC performance.

Main Methods:

• Numerical simulation and experimental fabrication of F-PSCs.
• Utilizing KBF4 as an additive to passivate trap defects in perovskite films.
• Characterization of perovskite films and device performance, including trap defect density, carrier lifetime, and PCE.

Main Results:

• KBF4 passivation significantly reduced the trap defect density in perovskite films from 8.0 × 10^15 cm^-3 to 3.9 × 10^15 cm^-3.
• The carrier lifetime of the perovskite films increased from 108.52 ns to 234.72 ns after KBF4 treatment.
• The PCE of the F-PSCs devices improved from 13.99% to 16.04% due to KBF4 passivation.

Conclusions:

• KBF4 effectively passivates trap defects in perovskite films by optimizing crystallinity and passivating grain boundaries.
• The enhanced perovskite film quality leads to a substantial increase in the PCE of flexible perovskite solar cells.
• This study highlights KBF4 as a promising additive for advancing the performance of F-PSCs for practical clean energy applications.