Ultra-Thin Lead Sulfide Capping for Stabilizing Tin Halide Perovskite Solar Cells

Area of Science:

• Materials Science
• Renewable Energy
• Photovoltaics

Background:

• Tin-based perovskite solar cells (PSCs) suffer from inherent instability, limiting their practical application.
• Developing strategies to enhance both stability and performance is crucial for advancing PSC technology.

Purpose of the Study:

• To introduce a facile method for simultaneously improving the stability and performance of tin-based PSCs.
• To investigate the dual-functional role of an ultra-thin lead sulfide (PbS) capping layer.

Main Methods:

• Sequential deposition of an ultra-thin (≈3 nm) dual-functional lead sulfide (PbS) capping layer.
• Characterization of the PbS layer's protective and electronic properties.
• Performance and stability testing of the modified tin-based PSCs.
• Operando grazing-incidence wide-angle X-ray scattering (GIWAXS) for structural analysis.

Main Results:

• The PbS capping layer effectively protects tin-based perovskites from oxidation and moisture.
• Improved interfacial electronic properties led to enhanced charge extraction and reduced non-radiative recombination.
• Power conversion efficiency (PCE) increased from 12.0% to 14.4% with an open-circuit voltage of 0.845 V.
• Exceptional long-term stability was achieved, with negligible PCE decay after 1600 hours.
• GIWAXS confirmed enhanced structural stability under operating conditions.

Conclusions:

• The ultra-thin PbS capping layer is a practical and effective strategy for stabilizing tin-based PSCs.
• This approach significantly enhances both the performance and operational lifetime of PSCs.
• The findings pave the way for the viable application of tin-based PSCs in sustainable photovoltaics.