Explore Amorphous Solar Cells and if a-Si Panels Are a Fit for You

lthough crystalline solar panels remain the go-to choice for most homeowners, the alternative solar energy industry is witnessing the rise of alternative technologies that come with their own advantages. Amorphous silicon solar cells (or a-Si) are one such technology that's capturing industry attention. In this article, we'll take a deep dive into the world of amorphous silicon solar panels, examining their composition, functionality, as well as the pros and cons they bring to the table. By the end, you'll have a solid grasp of what a-Si panels are all about and their potential role in shaping the future of clean energy.

Understanding the different types of solar panels

Going solar is a smart move for homeowners who want to cut down on energy costs and make a positive impact on the environment. But with various types of photovoltaic (PV) panels out there, it's crucial to know the nuances before deciding. The most widely used panel types are monocrystalline, polycrystalline, and thin-film.

Monocrystalline

Monocrystalline panels are a highly sought-after type of solar panel in the current market. These panels are made using a single silicon crystal, giving them a uniform black color. Monocrystalline solar panels are well-known for their exceptional efficiency and performance, making them a popular option for both residential and commercial installations. Moreover, they can withstand extreme weather conditions like high winds, hailstorms, and heavy snowfall for up to 25 years.

One of the significant benefits of monocrystalline panels is their remarkable efficiency. Residential monocrystalline panels can convert up to 23% of the sunlight they receive into electricity, which is significantly higher than other types. As a result, monocrystalline panels require less space to generate the same amount of electricity as other panels. In addition, they have an appealing, uniform appearance that makes them an ideal choice for residential installations where appearance is a crucial factor. Nevertheless, monocrystalline modules may carry a steeper price than other varieties.

Polycrystalline

Due to their cost-effectiveness, polycrystalline solar panels are a popular option for both residential and commercial installations. They consist of several silicon crystals that are melted together to form a single material, resulting in a surface with a speckled pattern and a blueish hue that is less uniform than that of their monocrystalline counterparts. Despite this, polycrystalline panels remain quite efficient, with an efficiency rating of around 16-18%.

Polycrystalline modules have a lifespan of up to 25 years or more and are known for their durability. They are also a more economical choice than their monocrystalline counterparts, making them an ideal option for those with a limited budget. In addition, polycrystalline panels are known for their high temperature tolerance, allowing them to perform well in hot and humid climates. However, one drawback is that they may require more space compared to monocrystalline panels, as they are less efficient at converting sunlight into energy.

Thin-film

Unlike traditional solar panels, made of silicon wafers, thin-film panels are composed of extremely thin layers of photovoltaic materials deposited on a substrate, such as glass or metal. This makes them much lighter and more flexible than traditional panels, and they can be easily integrated into a variety of applications, such as building facades, vehicles, and backpacks. Thin-film panels are also less expensive to produce than traditional ones, making them an attractive option for large-scale PV installations.

There are three primary types of thin-film solar: amorphous silicon (a-Si), cadmium telluride (CdTe), and copper indium gallium selenide (CIGS). Each has its unique traits and benefits. Amorphous silicon solar cells are widely used due to their high durability, low toxicity, and adaptability to various applications. Cadmium telluride options are highly effective and less expensive than crystalline silicon. Copper indium gallium selenide is a new technology that has become popular due to its high efficiency and ability to work well in low-light conditions. Now,  x let’s take a closer look at the a-Si technology.

Amorphous solar panel - an overview

Amorphous silicon solar panels are the pioneers and most mature form of thin-film PV technology that emerged in the late 70s. An amorphous solar panel operates on the same principle as a regular panel, using Si-based photovoltaic technology. However, instead of using individual cells made from Si wafers, it employs a thin layer of non-crystalline silicon that is applied to a substrate such as metal, glass, or plastic. So when you hear the term "amorphous silicon solar cells," you can think of it as a layer of silicon rather than discrete cells.

If you're wondering just how thin amorphous solar cells are, consider that a single layer of silicon on one of these modules can be as thin as a micrometer-thinner than a sheet of paper! As a result, amorphous solar cells are more flexible, crack-resistant and can be utilized in a variety of devices, such as calculators, outdoor lights, and small electronic gadgets.

How a-Si cells function

Amorphous silicon solar cells are made of a layer of silicon atoms arranged in a disordered, non-crystalline structure. This shapeless structure allows amorphous solar cells to absorb a broader range of light wavelengths than traditional c-Si cells, making them more efficient in converting sunlight into electricity. When photons of light hit the amorphous silicon layer, they get absorbed, liberating electrons from their parent Si atoms. These electrons then move towards the conductive layers in the cell, thereby generating an electric current. The current generated by amorphous solar cells is collected by conducting electrodes on the top and bottom of the cell.

Advantages of a-Si solar panels

Low production costs

One of the main advantages of an amorphous silicon solar panel is its low manufacturing costs. Unlike crystalline cells that require high-temperature processing and precise crystalline structures, amorphous solar cells can be produced at a much lower expense. The manufacturing process of an a-Si panel is more straightforward and requires fewer materials, resulting in a lower cost per watt of power produced.

Flexible and lightweight design

Another advantage of amorphous silicon solar cells is their flexibility and lightweight design. The a-Si material can be deposited on a variety of substrates, including plastics, glass, and metal foils, enabling the production of thin and flexible PV panels. When you need a panel that can handle the weight and shape constraints of portable devices, backpacks, and curved surfaces, the flexibility and lightweight design of an amorphous solar panel make it an ideal choice.

Better performance in high temperatures

A third advantage is better performance in high-temperature environments. Traditional c-Si cells experience a drop in efficiency as the temperature rises. In contrast, amorphous solar cells maintain their efficiency even in high-temperature environments. So if you live in a hot region like a desert or a tropical area, an amorphous solar panel may be a good choice.

Disadvantages of a-Si solar panels

Lower efficiency

The major disadvantage of a-Si panels is their lower efficiency when compared to other options. With an efficiency range of 6-8%, amorphous silicon solar cells require a larger surface area to produce the same amount of electricity as traditional cells, which can have an efficiency range of up to 23%. As a result, a-Si setups may not be the best option for applications where space is limited.

Shorter lifespan

An average amorphous solar panel has a lifespan of around 10-15 years, significantly shorter than traditional counterparts, which boast a durability of up to 25-30 years. This is because the amorphous silicon material used in a-Si modules degrades over time, leading to decreased efficiency and, ultimately, failure.

Limited applications

Lastly, amorphous silicon solar panels have limited applications due to their lower efficiency and shorter lifespan. They are not well-suited for large-scale power generation or applications where space is limited, such as rooftop solar systems. They are, however, suitable for smaller-scale applications such as powering electronic devices and calculators.

The future outlook for amorphous silicon solar technology

Amorphous solar panel technology may not have much potential for large-scale commercial applications, but it can still be useful in specific markets such as transparent windows, greenhouses, and indoor energy scavengers. Moreover, the knowledge gained from the progress of amorphous silicon solar cells has paved the way for developing valuable and cost-effective manufacturing processes for high-efficiency heterojunction cells.

Currently, researchers are dedicated to developing more efficient and cost-effective panels that combine c-Si heterojunction bottom cells with perovskite top cells, and amorphous interface layers will be vital in this process. Even though amorphous solar cells may not take the lead in the future of photovoltaic energy, they still have a significant part to play in driving innovation and progress in the industry.