Amorphous Silicon Solar Cells – An Overview of Efficiency, Structure, Working Principle, and More

The world of solar cells is going through a rapid transition. While there are different types of cells powering solar panels, let’s focus on the role of an amorphous silicon solar cell. They have a simple mechanism and lower production costs than a crystalline silicon cell. 

However, what are the advantages of amorphous silicon solar cells? How does the cell function and what is the efficiency rate? If you have similar questions, let’s begin exploring all of the topics.

Without wasting your time, let’s delve deeper into the basics of an amorphous silicon solar cell. 

What is an Amorphous Silicon Thin-Film Solar Cell?

Amorphous silicon solar cells, often referred to as a-Si solar cells, have gained prominence due to their commendable efficiency. Unlike traditional crystalline silicon solar cells, amorphous silicon solar cell efficiency is not dependent on a crystalline structure. This unique characteristic allows it to be more flexible, making it suitable for applications where rigid structures are impractical.

Let’s dive deeper into the structure of silicon solar cells.

Structure of Amorphous Silicon Solar Cells:

At its core, the amorphous silicon solar cell structure comprises of a thin layer of non-crystalline silicon. This thin film is typically deposited onto a substrate, creating a flexible and lightweight structure. The absence of a crystal lattice in amorphous silicon allows for a more straightforward manufacturing process and reduces material waste.

Working Principle of the Solar Cells

The working principle of amorphous silicon solar cells is rooted in the photovoltaic effect. Here is a complete structure of the mechanism of the cells.

I) Photovoltaic Effect:

Amorphous silicon solar cells operate based on the photovoltaic effect, a phenomenon where light energy is converted into electrical energy.

When photons from sunlight strike the thin layer of amorphous silicon, they transfer energy to the electrons in the material.

II) Generation of Electron-Hole Pairs:

The absorbed energy excites electrons in the amorphous silicon, allowing them to break free from their bound state within the atoms.

This process creates electron-hole pairs, where electrons become free to move, leaving behind positively charged “holes” in the material.

III) Electric Current Generation:

The movement of these free electrons creates an electric current within the amorphous silicon layer.

This flow of electrons is harnessed as electrical power, creating a direct current (DC) that can be utilized for various applications.

IV) P-N Junction Formation:

Amorphous silicon solar cells typically have a p-n junction, where one side of the silicon layer is doped with positive (p-type) and the other with negative (n-type) semiconductor material.

The p-n junction facilitates the separation of charge carriers, ensuring that electrons and holes move in the desired directions.

V) Electron Flow to External Circuit:

The electric current generated by the movement of electrons is then directed to an external circuit, allowing it to be used to power electronic devices or stored in batteries.

VI) Conversion of DC to AC (Optional):

In practical applications, the direct current (DC) generated by the solar cell may be converted into alternating current (AC) using inverters for compatibility with the electrical grid or appliances.

VII) Adaptability and Versatility:

The flexible nature of amorphous silicon allows for the adaptation of these solar cells to various surfaces and structures, enhancing their versatility in applications such as building-integrated photovoltaics (BIPV) and wearable technology.

Advantages of Amorphous Solar Silicon Cells:

1) Flexibility: Amorphous silicon solar cells can be fabricated on flexible substrates, enabling their integration into a variety of surfaces and structures.

2) Low-Light Performance: These solar cells exhibit good performance even in low-light conditions, making them suitable for regions with varying sunlight intensities.

3) Cost-Effective Production: The manufacturing process for amorphous silicon solar cells is simpler compared to crystalline silicon cells, potentially reducing production costs.

4) Versatility in Applications: Due to their flexibility, amorphous silicon solar cells can be incorporated into unconventional applications, such as clothing, windows, and curved surfaces.

Disadvantages of Amorphous Silicon Solar Cells:

I) Lower Efficiency: While efficiency has improved over time, amorphous silicon solar cells generally have lower efficiency compared to some crystalline silicon counterparts.

II) Degradation Over Time: These solar cells may experience performance degradation over time, reducing their overall lifespan and efficiency.

III) Material Limitations: Amorphous silicon is more susceptible to light-induced degradation, limiting its use in high-intensity sunlight environments.

IV) Manufacturing Challenges: Achieving uniformity in the deposition process of amorphous silicon can be challenging, affecting the overall performance of the solar cells.

Now that you are aware of the amorphous silicon solar cells advantages and disadvantages, let’s explore the difference between amorphous and monocrystalline cells. 

Amorphous Silicon Solar Cells vs. Monocrystalline Solar Cells:

Here is a detailed tabular sheet representing the amorphous silicon solar cell vs. monocrystalline solar.

Feature	Amorphous Silicon Solar Cells	Monocrystalline Solar Cells
Structure	Non-crystalline thin film	Single-crystal structure
Efficiency	Moderate to high efficiency, improving	High efficiency, stable performance
Flexibility	Flexible and adaptable to various surfaces	Rigid structure limits flexibility
Manufacturing Process	Simpler and potentially cost-effective	More complex and costly
Low-Light Performance	Good performance in low-light conditions	High efficiency even in low-light

Finally, let’s explore the frequently asked questions for an amorphous silicon solar cell. 

FAQs – Amorphous Silicon Solar Cell

Why do amorphous solar cells have higher absorption than crystalline solar cells?

Amorphous solar cells generally exhibit higher absorption than crystalline solar cells due to the unique structure of amorphous silicon. In crystalline solar cells, the orderly arrangement of atoms in the crystal lattice can result in some photons having insufficient energy to dislodge electrons.

In contrast, the disordered, non-crystalline structure of amorphous silicon allows for a broader range of photon energies to be absorbed.

What is hydrogenated amorphous silicon used for?

Hydrogenated amorphous silicon (a-Si: H) is widely used in thin-film solar cell technology. The addition of hydrogen during the deposition process improves the material’s optoelectronic properties, making it more efficient in converting sunlight into electricity. 

Hydrogenation enhances the stability of amorphous silicon, mitigating the effects of light-induced degradation.

Is microcrystalline silicon amorphous?

No, microcrystalline silicon is not amorphous. Microcrystalline silicon is a form of silicon that contains small crystalline structures embedded in an amorphous silicon matrix. 

While it has some degree of crystallinity, it is not entirely crystalline like monocrystalline silicon. The mixture of crystalline and amorphous regions in microcrystalline silicon allows for improved efficiency compared to purely amorphous silicon solar cells.

What are silicon solar cells?

Silicon solar cells are devices that convert sunlight into electrical energy through the photovoltaic effect. These cells are typically made from crystalline silicon, which can be either monocrystalline or polycrystalline. When exposed to sunlight, the semiconductor material in silicon solar cells absorbs photons, generating electron-hole pairs.

What are the advantages of silicon solar cells over amorphous silicon solar cells?

• Higher Efficiency: Silicon solar cells, especially monocrystalline ones, often have higher efficiency compared to amorphous silicon solar cells.
• Longer Lifespan: Silicon solar cells generally have a longer lifespan and are more durable over time.
• Stability: Silicon solar cells exhibit greater stability and lower degradation rates than some amorphous silicon counterparts.
• Wider Range of Applications: Silicon solar cells are versatile and can be used in various applications, including residential, commercial, and utility-scale installations.

Why is silicon used for solar cells?

Silicon is used for solar cells due to its semiconductor properties and abundance. Silicon is a crucial element in the production of solar cells because of its ability to form a stable crystalline structure. This structure allows for the efficient generation and movement of charge carriers when exposed to sunlight.

Conclusion:

In conclusion, amorphous silicon solar cells offer a promising avenue for the future of solar energy. Their unique structure, working principles, and versatility in applications make them a compelling choice, especially in scenarios where flexibility and adaptability are paramount. 

While challenges such as lower efficiency and potential degradation exist, ongoing research and development efforts continue to address these issues, paving the way for a more sustainable energy landscape.

Are you ready to invest in solar projects, get started with Sustvest to make your investment journey a smooth ride. 
Also read: Solar Panels for Agriculture in India: Cultivating the Green Revolution.