Efficient and Stable Planar n-i-p Sb₂Se₃ Solar Cells Enabled by Oriented 1D Trigonal Selenium Structures.

Area of Science:

• Materials Science
• Renewable Energy
• Solid-State Physics

Background:

• Antimony selenide (Sb₂Se₃) solar cells are promising due to their environmental friendliness and cost-effectiveness.
• Achieving high efficiency in planar Sb₂Se₃ solar cells requires addressing surface defects and optimizing charge transport.

Purpose of the Study:

• To enhance the efficiency and stability of planar n-i-p Sb₂Se₃ solar cells.
• To investigate the effects of Sb₂Se₃ surface modification with oriented 1D van der Waals material, trigonal selenium (t-Se).

Main Methods:

• Fabrication of highly crystalline Sb₂Se₃ absorbers using seed layer assisted successive close spaced sublimation (CSS).
• Introduction of reactive selenium to compensate surface Se deficiency and form a 1D t-Se interlayer.
• Characterization of Sb₂Se₃ surface properties, including Se deficiency and negative surface band bending.

Main Results:

• The Sb₂Se₃ absorber exhibited a Se-deficient surface and negative surface band bending.
• The introduced p-type t-Se interlayer facilitated favorable band alignment and bending at the Sb₂Se₃/t-Se interface.
• A planar Sb₂Se₃ solar cell achieved a record efficiency of 7.45% for CSS-fabricated devices.
• The all-inorganic Sb₂Se₃ solar cell with t-Se demonstrated excellent stability, retaining 98% efficiency after 40 days in open air.

Conclusions:

• Sb₂Se₃ surface modification with oriented 1D t-Se effectively passivates the surface and enhances hole transport.
• The developed strategy significantly suppresses interface recombination and boosts carrier extraction efficiency.
• This approach offers a viable pathway for high-efficiency and stable planar Sb₂Se₃ solar cells.