Monocrystalline vs Polycrystalline Solar Panels: Everything You Should Know

If you’re planning a home solar installation, an important question to ask is what type of solar panel will work best for you. Most of the time, you will have one of two options: monocrystalline solar panels or polycrystalline solar panels. (A third type of solar panel, thin-film solar panels, also exists, but is uncommon in residential solar solutions.)

Today, we’ll give you everything you need to know about these two types of solar panels and give you the information you need to make an informed decision about home solar panels.

 

History of Solar Cell Technology

Humans have been attempting to harness the sun’s energy for millennia. During the Bronze Age (around 4,000 years ago), Chinese people carried around hand mirrors used to light fires. This technology was also known and used by the ancient Greeks and Romans, who regularly carried tools known as burning mirrors. But the real potential of solar energy comes from the photovoltaic effect.

 

The Photovoltaic Effect

The photovoltaic (or photoelectric) effect occurs when certain materials, such as silicon, are exposed to light. These materials absorb photons (particles of light) and release electrons from their atoms. This creates a flow of electrons, generating an electric current. The key component of a solar panel is the photovoltaic cell, which consists of multiple layers of specially treated silicon. These layers are designed to create an electric field that separates the freed electrons, allowing them to be captured and channeled as usable electricity. The photovoltaic effect converts sunlight directly into electrical energy, enabling solar panels to produce clean and sustainable power.

It is said that the photovoltaic effect was discovered in 1839 by French physicist Alexandre Edmond Becquerel. However, Becquerel’s work was with something slightly different– the photogalvanic effect– and so while he regularly receives credit for discovering the photovoltaic effect, the true photovoltaic effect wasn’t discovered until 1872, by British scientists William Grylls Adams and Richard Evans Day. Their work relied on Willoughby Smith’s work on the photoconductivity of selenium in the 1860s. Eleven years later, in 1883, American inventor Charles Fritts made the first solar cells from selenium, which were about 1% efficient.

The next major breakthrough in solar power occurred in the early 1900s, when Albert Einstein published four papers in 1905 about the photovoltaic effect. It was a major part of the reason he won the 1922 Nobel Prize in physics.

What we think of as solar power today was created in 1954 at Bell Laboratories. On April 25, 1954, Bell scientists publicly demonstrated the first silicon solar cell, which was about 6% efficient. All of today’s solar cells are essentially improvements on this design.

Since then, solar technology has developed in leaps and bounds. Throughout the 1960s and 1970s, solar technology continued to advance, but its use was primarily limited to space exploration and niche applications due to its high cost. The oil crisis of the 1970s, however, prompted increased interest in renewable energy sources, including solar power.

In the 1980s, there was a significant growth in solar power installations, driven by government incentives and the development of new technologies. This period saw the introduction of thin-film solar cells, which today are used for off-grid installations and small panels like those used with solar generators, as well as overall improvements in the efficiency and affordability of photovoltaic panels.

As the 21st century progressed, solar power became more widely adopted. The cost of solar panels decreased, and their efficiency improved. Governments around the world implemented policies to promote renewable energy, including solar, as a means to reduce greenhouse gas emissions and combat climate change.

Today, solar power is a rapidly expanding source of electricity generation. Large-scale solar farms are being built around the world, and residential and commercial solar installations have become more commonplace. In addition to the traditional silicon-based solar panels, there is ongoing research and development into alternative materials, such as perovskite and organic solar cells, which could further enhance the efficiency and versatility of solar power.

 

What is a Monocrystalline Solar Cell?

A monocrystalline solar cell is a type of solar cell made from a single silicon crystal structure. It is typically composed of a high-purity silicon ingot that is grown in a controlled environment. The crystal structure of monocrystalline cells is uniform and highly ordered, which results in high efficiency and performance. Monocrystalline solar cells have a distinctive appearance with a smooth, even black color. They are known for their high efficiency levels.

 

What is a Polycrystalline Solar Cell?

Polycrystalline solar cells, also known as multicrystalline cells or just abbreviated as poly cells, are made from multiple silicon crystals. The manufacturing process involves melting fragments of silicon together, resulting in a less uniform crystal structure with visible grain boundaries. Polycrystalline solar cells have a blueish appearance due to their uneven coloration.

While poly cells are slightly less efficient than monocrystalline cells, they are less expensive to produce, making them a popular choice for many solar installations. Advances in technology have narrowed the efficiency gap between the two types, and both monocrystalline and polycrystalline solar cells remain widely used in the solar industry.

 

Monocrystalline vs Polycrystalline Solar Panels At A Glance

 

N-type vs. P-type Cells

In addition to choosing between monocrystalline and polycrystalline solar panels, you also must consider N-type and P-type cells. N-type and P-type cells refer to the two types of semiconductor materials used in solar cells. Solar cells are not made with pure silicon; instead, the silicon is “doped” with impurities to improve photovoltaic efficiency and the generation of an electric field.

N-type cells have impurities that provide excess electrons (a negative charge), while P-type cells have impurities that create electron deficiencies, known as holes, that have a positive charge. The junction formed between N-type and P-type layers creates a built-in electric field that enables the separation and flow of electrons when exposed to light.

 

N-Type Cells and P-Type Cells At A Glance

 

 

N-type or P-type?

If you are installing commercial solar panels, you might not have a choice of N-type or P-type, depending on what your installer has available. If you don’t have a choice, your solar panels will likely use P-type cells.

P-type cells have dominated the market for the last 40 years. While the original solar cell was an N-type cell, P-type cells are much more resistant to radiation. Since much of the original solar energy development was created for use in space, P-type cells received much more attention in research and development.

P-type cells also are more common due to their lower production costs and overall good performance. N-type cells are more expensive. However, they are significantly more efficient than P-type cells and have better heat tolerance. Additionally, P-type cells are prone to performance-reducing light induced degradation (LID), which can decrease their efficiency by up to 10% over time. LID is much less of a problem with N-type cells. N-type cells are more durable and last longer, and improvements in development and demand for this type of cell are driving the price down.

Ultimately, if cost is a concern, solar panels with P-type cells will be more budget-friendly. But if you can afford them and they are an option that your solar installer provides, N-type cells will last longer and contribute to higher efficiency.

 

Monocrystalline vs. Polycrystalline: Which Solar Panels are More Efficient?

Monocrystalline panels are known for their higher efficiency levels compared to polycrystalline panels. This efficiency advantage can be attributed to the uniform and highly ordered crystal structure of monocrystalline cells. The single-crystal structure allows for better electron flow within the material, resulting in higher conversion rates of sunlight into electricity.

Monocrystalline panels typically have efficiencies ranging from 15% to 23%. The highest efficiency rating produced in lab conditions was 47.6% for a monocrystalline panel, and the technology is always improving.

On the other hand, polycrystalline panels have a less uniform crystal structure, with visible grain boundaries. This structure introduces some inefficiencies due to the presence of these boundaries, which can impede the flow of electrons.

As a result, polycrystalline panels generally have slightly lower efficiencies compared to monocrystalline panels. Polycrystalline panels typically have efficiencies ranging from 13% to 17%.

The difference in efficiency alone may not be significant enough to outweigh other factors, but it is definitely worth considering. This means that if you only have a small area to place solar panels, monocrystalline panels are likely the best choice. However, they are more expensive than poly panels, so take that into consideration if you’re considering a home solar installation. Every residential solar installation is different, so take all of your needs into consideration when choosing between monocrystalline vs. polycrystalline solar panels.

 

How Long Do Monocrystalline and Polycrystalline Solar Panels Last?

Both monocrystalline and polycrystalline solar panels are designed to be durable and have a long lifespan. On average, these panels can last for 25 to 30 years. Usually, the maximum manufacturer warranty is 25 years.

It’s important to note that while the efficiency of solar panels may degrade over time, they will still continue to generate electricity even after reaching the end of their specified lifespan– they just won’t be as efficient. Depending on how much sun you get, that might not matter much for your household’s personal use, but it may affect how much money you can make back through net metering.

However, just because solar panels can maintain their efficiency for decades, that doesn’t mean they necessarily will. Environmental conditions can have a major impact on the lifespan of your solar panels. Solar panels have to hold up under temperature, UV exposure, humidity, rainfall, storms, and other environmental stressors.

Generally speaking, monocrystalline panels are better if you’re in a hot area. The cells hold up better under high temperatures, meaning that the panel will last longer. However, heat isn’t the only weather condition that affects the longevity of solar panels.

Extreme temperatures, excessive humidity, and exposure to saltwater or corrosive elements can potentially impact their performance and lifespan. In addition to the solar cells themselves, the panels’ housing, mounts, and other build elements contribute to how long each panel lasts.

Proper installation and maintenance are essential for maximizing the lifespan of solar panels. When panels are installed correctly, securely mounted, and properly wired, they are less likely to experience premature failures or damage. Regular inspection and maintenance, including cleaning debris and dust from the surface of the panels, can help optimize their performance and prevent issues that may impact their lifespan.

 

Final Thoughts

Both monocrystalline and polycrystalline solar panels will work in many residential solar applications. However, certain residential conditions will often favorably indicate one type over the other. If you’re in a small space or have a large budget for solar panels, monocrystalline panels are the more efficient of the two. But if budget is a concern, polycrystalline panels are often substantially less expensive.

Ultimately, each solar installation is unique. When shopping for solar panels, make sure you consider your specific energy needs. Once you know what you need, your installer will help find the best panels for you.