• April 15, 2024
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Solar cells are the devices that convert light energy into electrical energy and are an integral part of the renewable energy sector. As technology advances, the solar cell industry is constantly evolving, leading to the development of multi-junction solar cells. In this blog, we will take a deep dive into what multi-junction solar cells are, how they work, and why they are considered as the future of solar energy.

What are Multi-Junction Solar Cells?

Multi-junction solar cells are a type of photovoltaic (PV) cell that consist of multiple layers of semiconductor materials. Each layer is optimized to absorb a different range of the light spectrum, allowing the cell to absorb a wider range of light energy and increase the overall efficiency. In contrast, traditional single-junction solar cells only contain one layer of material and are limited to absorbing a narrow range of light.

How do Multi-Junction Solar Cells work?

The working principle of multi-junction solar cells is based on the concept of bandgap energy. The bandgap energy is the minimum amount of energy required to free an electron from its orbit and allow it to move freely in the material. Different materials have different bandgap energies, and different light wavelengths correspond to different amounts of energy.

Multi-junction solar cells have multiple layers of different materials, each with a different bandgap energy. When light enters the cell, it is absorbed by the top layer, which has the highest bandgap energy. The absorbed energy frees electrons from the material, and they flow freely to the next layer, which has a lower bandgap energy. This process continues until all the electrons have reached the bottom layer, and the electrical energy is collected and converted into usable power.

Why are Multi-Junction Solar Cells considered the future of Solar Energy?

Multi-junction solar cells have several advantages over traditional single-junction solar cells, making them the future of solar energy. Some of the key benefits include:

Increased Efficiency:Multi-junction solar cells have a much higher efficiency compared to traditional single-junction solar cells. This is due to the ability of multi-junction cells to absorb a wider range of light energy, resulting in a higher conversion rate.

Improved Performance:Multi-junction solar cells perform better in low-light conditions and perform better in high temperatures, making them ideal for use in harsh environments.

Cost-Effective:Despite the higher cost of manufacturing multi-junction solar cells, their increased efficiency and performance make them a cost-effective solution in the long run.

Space and Weight Savings: Multi-junction solar cells are lighter and smaller than traditional single-junction solar cells, making them ideal for use in space applications and other weight-sensitive applications.

Durability: Multi-junction solar cells are more durable than traditional single-junction solar cells and can withstand extreme temperatures and other harsh environmental conditions.

What is the manufacturing process of multijunction solar cells?

The manufacturing process of multijunction solar cells typically involves several steps, including:

Growth of the semiconductor material: The semiconductor material is grown in a controlled environment using methods such as molecular beam epitaxy (MBE) or metal-organic chemical vapor deposition (MOCVD).

Deposition of the metal contacts: Metal contacts are deposited on the surface of the semiconductor material to allow for electrical connection to the rest of the circuit.

Formation of the p-n junctions: The p-n junctions are formed by doping the semiconductor material with impurities to create an electric field. This is done using a variety of techniques, such as ion implantation or diffusion.

Assembly of the solar cell: The solar cell is assembled by connecting the metal contacts to the p-n junctions and encapsulating the cell in a protective material to prevent damage from environmental factors.

Testing and quality control: The completed solar cell is tested to ensure it meets specifications and quality standards, including efficiency and stability.

Each step of the process must be carefully controlled and optimized to produce high-quality, efficient multijunction solar cells. The exact process may vary depending on the specific materials and technology used, but the overall goal is to create a solar cell with multiple layers of semiconductor material that can capture and convert a wide range of solar radiation into electrical energy.

See AlsoHow is Solar Manufacturing Done?

Multi-junction solar cells: what is their highest efficiency?

As of 2021, the highest efficiency of multi-junction solar cells is 46.1%, which was achieved by a team of researchers from the National Renewable Energy Laboratory (NREL) in the United States.

Limitations of Multijunction solar cells.

  1. High Cost: Multijunction solar cells are much more expensive compared to traditional single-junction solar cells, making them less accessible to the general population.
  2. Complex Manufacturing Process: The manufacturing process of multijunction solar cells is complex and requires specialized equipment, which makes it difficult for manufacturers to scale up production.
  3. Fragile Structure: Multijunction solar cells have a delicate structure that is prone to damage, which can reduce their efficiency and lifespan.
  4. Limited Efficiency: Despite having higher conversion efficiencies than single-junction solar cells, multijunction solar cells still have a limited efficiency, meaning that they can only convert a certain amount of sunlight into electricity.
  5. Maintenance Requirements: Multijunction solar cells require regular maintenance to keep them functioning at peak efficiency, which can increase the overall cost of ownership.
  6. Limitations in Cell Design: The design of multijunction solar cells is limited, as the materials used in their construction must meet specific requirements in order to be effective.
  7. Incompatibility with Existing Infrastructure: Multijunction solar cells are not compatible with existing solar infrastructure, which can make it challenging to integrate them into existing systems.

Comparison between Single Junction and multijunction solar cells

Feature

Single Junction Solar Cells

Multijunction Solar Cells

Efficiency

15-20%

40-50%

Cost

Low

High

Material

Silicon

Multiple semiconducting materials

Design

Simple

Complex

Spectral response

Limited to specific range

Broad spectral response

Temperature sensitivity

High

Low

Lifetime

Moderate

Long

Note: The above data is based on average and may vary based on the specific product and technology used.

Conclusion

In conclusion, multi-junction solar cells are the future of solar energy due to their increased efficiency, improved performance, cost-effectiveness, space and weight savings, and durability. As technology continues to evolve, it is likely that we will see further improvements in multi-junction solar cell technology, leading to even greater efficiency and performance. If you're looking to invest in renewable energy, consider investing in multi-junction solar cells with Waaree Energies. Call now at 18002121321 or Email at waaree@waaree.com to start/advance your solar journey.

Also Read more information : Solar cells: What is the future?

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