Homogenizing Vertical Strain Distribution Enables High-Performance Tin-Based Perovskite Solar Cells With Thicker...

Area of Science:

• Materials Science
• Renewable Energy
• Photovoltaics

Background:

• Solution-processed tin-based perovskite solar cells (TPVSCs) have limited power conversion efficiency (PCE) due to restricted active layer thickness.
• Increasing active layer thickness in TPVSCs causes lattice strain and rapid crystallization, leading to defects and poor electron diffusion.

Purpose of the Study:

• To overcome the efficiency limitations of TPVSCs by addressing issues related to active layer thickness.
• To improve the lattice homogeneity and crystallization kinetics in tin-based perovskite devices.

Main Methods:

• Introduction of reductive 4,4 -thiobisbenzenethiol (TBBT) to form bidentate coordination with Sn²⁺ ions.
• Relaxation of Sn-I bonds to improve lattice homogeneity.
• Retardation of crystallization kinetics to match electron diffusion length with absorber thickness.

Main Results:

• Achieved excellent power conversion efficiencies (PCEs) of 15.02% for rigid and 12.43% for flexible devices (0.04 cm²).
• Demonstrated high PCE of 13.37% for rigid devices (1.00 cm²).
• Unencapsulated rigid devices showed T₉₅ of 3500 h shelf life and T₉₀ of 684 h under MPP tracking; flexible devices retained 85% PCE after 4000 bending cycles.

Conclusions:

• The addition of TBBT synergistically enhances both efficiency and stability in tin-based perovskite solar cells.
• The strategy effectively addresses the challenges of active layer thickness and defect formation in TPVSCs.
• This work presents a promising approach for developing high-performance and durable perovskite solar technologies.