Advancing Solar PVs with Antimony Selenide as the Semiconductor in Tandem Solar Cells

Antimony selenide (Sb₂Se₃) has shown great potential to boost solar energy efficiency.

The Basics of Sb₂Se₃

Antimony selenide is a semiconductor with a band gap of 1.05–1.2 eV, which means it is very useful for converting sunlight to electricity. It has been widely used in single-junction solar cells due to its favourable properties, such as high absorption coefficients and stability. Sb₂Se₃ is composed of non-toxic and abundant elements, which makes it environmentally friendly and cost-effective.

What Are Tandem Solar Cells?

Tandem solar cells are a type of solar technology designed to surpass the efficiency limits of traditional single-junction cells. By stacking two or more layers of different semiconducting materials, tandem cells can capture a broader spectrum of sunlight, thereby increasing their overall efficiency. Typically, these cells consist of a “top” cell that absorbs high-energy photons and a “bottom” cell that captures lower-energy photons passing through the top layer.

The Breakthrough: Perovskite/Sb₂Se₃ Tandem Solar Cells

In a groundbreaking study, researchers have successfully demonstrated a four-terminal (4-T) tandem solar cell using Sb₂Se₃ as the bottom cell material and a wide-bandgap perovskite material as the top cell. The perovskite layer, known for its adjustable band gap, enhances the overall absorption spectrum, while Sb₂Se₃ contributes to stability and efficient use of lower-energy photons.

The Role of Transparent Conducting Electrodes

One of the critical components in this tandem cell structure is the transparent conducting electrode (TCE). The TCE not only collects charges but also allows light to pass through to the bottom cell. The researchers used indium-doped zinc oxide (IZO) for this purpose, which demonstrated excellent conductivity and transparency, crucial for high-efficiency solar cells.

Achieving High Efficiency

By meticulously adjusting the thickness of the IZO layer, the top perovskite cell achieved an efficiency of 17.88%. The Sb₂Se₃ bottom cell, enhanced with a double electron transport layer, delivered an efficiency of 7.85%. When combined in the tandem structure, these cells achieved an impressive overall efficiency exceeding 20%.

Advantages and Future Prospects

The study showcases several advantages of using Sb₂Se₃ in tandem solar cells:

1. High Stability: Sb₂Se₃-based cells exhibit excellent stability over time.
2. Environmental Friendliness: The material is composed of non-toxic elements.
3. Cost-Effectiveness: Sb₂Se₃ is made from abundant materials, reducing production costs.

The successful demonstration of a perovskite/Sb₂Se₃ tandem solar cell marks a significant step forward in solar technology. With further optimisation and scaling, this approach could lead to commercially viable solar cells with much higher efficiencies than currently available.

The integration of antimony selenide in tandem solar cells represents a promising development in photovoltaic technology. By leveraging the unique properties of Sb₂Se₃ and combining it with innovative materials like perovskites, researchers are paving the way for more efficient and sustainable solar energy solutions. This advancement holds the potential to significantly enhance the performance of solar panels, making solar power an even more attractive option for addressing global energy needs.

Source

Sb₂Se₃ as a bottom cell material for efficient perovskite/Sb₂Se₃ tandem solar cells, Energy Materials and Devices, 2024-03-04