Key points on PERC cells:
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PERC solar cells are generally more efficient and resistant to heat than traditional silicon crystal cells.
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Using PERC cells in solar panels can increase their average efficiency from around 18% to over 21%.
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PERC solar cells are still subject to some of the same limitations as traditional solar cells.
There are a lot of developments worth paying attention to in the solar industry, but few have made as big of a splash as PERC solar cells. These cells are the next step in solar technology evolution, offering improved efficiency and performance under stressful conditions.
We created this guide to PERC solar cells to help you understand this exciting emerging technology. You’ll learn how they work, how they’re different from traditional cells, and what advantages they can offer you for your solar energy setup.
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What is passivated emitter rear cell (PERC) solar technology?
PERC is a high-efficiency solar technology. It adds a dielectric layer to silicon cells. This layer reflects light and reduces recombination. The result is better light trapping and higher power conversion efficiency (PCE).
In effect, panels outfitted with PERC photovoltaic cells generate more energy than traditional panels of the same size under the same conditions.
How do PERC cells compare to traditional options?
Monocrystalline and polycrystalline cells are standard silicon-based PV technologies. Both can use PERC cells, and these are known as mono PERC and poly PERC. Mono PERC offers the highest performance, while poly PERC is a cost-effective upgrade over traditional polycrystalline panels.
Conventional monocrystalline and polycrystalline solar cell design
Traditional monocrystalline and polycrystalline solar cells are made with a layered construction that includes the following components:
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Front contact: Collects electrical currents produced in the cell
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Anti-reflective coating: Helps trap and absorb sunlight
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N-type silicon layer: Top layer of the cell where sunlight enters
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P-type silicon layer: Bottom layer that completes the diode
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Back contact: Closes the cell and collects electrical currents
This design encourages electron movement when sunlight hits the cell. Photons excite electrons, creating electron-hole pairs. The cell’s electric field drives electrons toward the n-layer and holes to the p-layer. Electrons flow through an external circuit, generating usable electricity to power your home.
Mono PERC and poly PERC solar cell design
The architecture of PERC cells is basically the same as conventional cells, with a few important distinctions. The key differences are:
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Dielectric Passivation Layer: A thin rear coating of aluminum oxide (Al₂O₃) or silicon nitride (SiNx) minimizes carrier recombination and enhances light trapping by reflecting unabsorbed photons.
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Laser Contact Openings (LCO): Precision laser ablation creates micro-openings in the passivation layer. This creates rear-side electrical contact without compromising insulation.
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Rear Metal Contact: Improves charge collection and ups solar efficiency by reducing energy losses from carrier recombination.
How do PERC panels increase solar efficiency?
Based on industry research, PERC solar cells tend to increase solar cell efficiency by 1 to 1.5%. This is a more significant boost than it may sound like at first. As a result of this improved efficiency, PERC solar cells can increase the solar panel efficiency—or, the amount of sunlight converted to energy—from around 18% to 21%.
PERC boosts efficiency through two mechanisms:
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Rear surface passivation: PERC cells reduce electron recombination losses, increasing the amount of electrons that can contribute to energy creation.
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Light trapping: The dielectric layer in PERC cells reflects infrared light that is lost in traditional panels. This gives photons in sunlight a second chance at stimulating electron activity.
Are PERC cells more expensive?
Yes, PERC cells are typically more expensive than standard monocrystalline or polycrystalline cells. This is because they take more time and resources to manufacture.
That said, PERC cells offer better energy yield per square foot, which can lower your system’s levelized cost of electricity (LCOE) over time. For many, the long-term savings and performance gains justify the upfront cost.
Why use PERC PV modules?
PERC solar cells are ideal for residential rooftops, commercial buildings, and utility-scale solar farms. Their high efficiency makes them perfect for limited space. Strong performance in heat and shade suits diverse environments and improves the energy yield you can get.
Below are a few main benefits.
Higher energy yields
PERC cells can create more energy under the same conditions as traditional cells. This makes them more efficient overall, but even more useful in low-light, cloudy, or angled-light conditions.
Better temperature coefficients
Solar panels with PERC cells also perform better in high-temperature environments, which are unfavorable to the efficiency of traditional cells.
Lower levelized cost of electricity (LCOE)
The superior efficiency of PERC solar cells means that they can produce more electricity per unit area, reducing the per-kWh cost of the system.
What are the downsides to PERC solar cell architecture?
While PERC solar cells are indeed a breakthrough in solar technology, they still have some weaknesses. These include:
Light-induced degradation (LID)
All solar panels suffer a gradual loss in efficiency over time due to sunlight exposure, including those with PERC cells. Treatments like gallium doping can help reduce LID.
Potential induced degradation (PID)
Like other solar cells, PERC cells are also subject to efficiency loss from leaking “stray” currents. Improved encapsulation materials and design, plus better grounding systems, can help reduce the effects of PID.
Heat accumulation
The rear layer in PERC cells traps more light than traditional solar cells, which can increase the temperature of the cell and reduce efficiency and longevity.
Who manufactures PERC solar cells?
Top PERC solar cell manufacturers like LONGi, JA Solar, and JinkoSolar offer high-efficiency PV modules for residential and utility applications. Manufacturers use a combination of bifacial cells, light-trapping layers, and laser contact openings in various products.
Variants and evolving competitors to PERC solar technology
While PERC solar cells are quickly gaining ground in the industry, they aren’t the only emerging solar technology in development. There are a few other types of solar cells being researched for commercial production. Some of the other developing technologies include:
Tunnel oxide passivated contact (TOPCon)
These cells are a more advanced form of PERC solar cells that offer superior passivation and contact quality.
Heterojunction technology (HJT)
This newer type of solar cell combines crystalline and amorphous silicon layers to increase power output.
Bifacial PERC
This construction allows PERC cells to capture energy from both front and rear sides, resulting in even greater solar efficiency.
Bottom line on PERC solar cell technology
PERC solar cells are an exciting area of development for the solar industry. While they don’t solve all the problems inherent to traditional crystalline panels, they offer the promise of more efficient panels and the potential for lower startup costs in the future. As more research goes into the development and manufacturing of PERC cells, you can expect to see more and more of them on the market.
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This article is part of our expert series on solar panel technology, which also includes:
You might also find these in-depth solar guides useful:
Taking your time to research is important, because solar panels aren’t always best for every situation.
PERC solar cell FAQ
Below are a few frequently asked questions about PERC solar cells:
What are the disadvantages of PERC solar panels?
PERC solar cells can suffer from light-induced degradation (LID), potential induced degradation (PID), and overheating from enhanced light trapping. These issues may reduce efficiency and lifespan, especially in harsh environments, despite their performance advantages over standard silicon solar cells.
What is the difference between TOPCon and PERC solar cells?
TOPCon solar cells improve on PERC by adding a tunnel oxide layer and passivated contact, boosting efficiency and reducing recombination. While PERC is more affordable and widely adopted, TOPCon offers higher performance, especially in power conversion and thermal stability.
If you want to learn more, please visit our website PERC PV Module.
Is mono-PERC or monocrystalline better?
Mono-PERC cells tend to offer better efficiency than monocrystalline solar cells. This is especially true in low-light and high-heat conditions.
What is the lifespan of a PERC solar panel?
The typical lifespan of a PERC solar panel is 25 to 30 years. With proper installation and maintenance, they maintain high efficiency for decades, though some performance loss may occur over time due to environmental factors and material degradation.
Do PERC solar panels work well with solar batteries?
In the never-ending quest for increased solar panel efficiency, materials engineers try a lot of different things to make photovoltaic cells turn solar energy into as much electricity as possible.
One of the most important and mature technologies to do that is through something called PERC, which stands for “Passivated Emitter and Rear Contact”, and is also sometimes called “Passivated Emitter and Rear Cell.”
Most people don’t really have a reason to care about PERC, but what’s important to know is that, until recently, it was the most popular way to manufacture solar cells. PERC technology is a simple and cost-effective way to make more power from the same amount of space, but most manufacturers have moved on to a new technology called TOPCon.
If you’ve gotten a quote from a solar installer and are choosing between different solar panels and price points, you might be interested to know about how high-efficiency PERC solar panels compare to other varieties of solar panels.
What are PERC solar cells?
PERC is a technology which is used to improve the efficiency of solar cells by capturing as many extra photons as possible without fundamentally changing how a solar cell works.
In ordinary crystalline silicon solar cells, electricity is produced when photons hit a layer of silicon, knocking electrons loose and then directed to flow along a wire. In general, modern monocrystalline silicon solar cells can convert about 20-25% of the incoming photons to electricity, but some photons pass through the silicon material without exciting electrons.
When these cells are built into a solar module, the unconverted photons can hit the aluminum back layer and turn into heat, which reduces cell efficiency. Other photons excite electrons that end up getting recombined without flowing through the cell’s wires, meaning they don’t generate electricity.
Typical silicon solar cells
The diagram below shows a cross section of a typical solar cell built into a module. These are the layers, from top to bottom:
PERC solar cells
To make a PERC solar cell, a manufacturer takes standard monocrystalline silicon cells and adds a passivation layer to the back that is designed to reflect photons back through the silicon layer. The cells are then micro-etched with chemicals or a laser to cut through the passivation layer so that the back contacts can reach it. A dielectric capping layer is added over the passivation layer to insulate the solar cell.
When built into a solar module, the passivation and capping layers prevent electrons from hitting the back contact on top of which the cells are laid. PERC cell technology makes it so that more photons are captured by the silicon, meaning each cell makes a little more electricity than it would without the PERC layers. The maximum efficiency of PERC cells is about 23%, compared to about 21% for traditional monocrystalline silicon cells.
The diagram below shows a cross section of a PERC solar cell built into a module. These are the layers, from top to bottom:
Front contact
Anti-reflective glass
Negative (n-type) silicon layer
Positive (p-type) silicon layer
Local back surface fields
Passivation layer
Dielectric capping layer
Rear contact
Pros and cons of PERC technology
PERC technology is not a new technology, having been invented in by Australian scientist Martin Green and his team at the University of New South Wales.
But commercially-available PV modules built using PERC solar cell technology are relatively new because materials scientists had to solve some problems before bringing the technology to market.
Pros
As we described above, PERC technology reflects photons back into the silicon layers, causing the cell to produce more power and preventing electron recombination. These two benefits result in increased energy conversion efficiency and decreased heat in solar modules. They also ensure the cells work better in low light by producing meaningful voltage with less light than standard solar cells.
Finally, PERC solar cells are relatively easy to make because manufacturers can use almost all of the same equipment and materials they use to make less-efficient solar cells. PERC technology can be added to both mono and polysilicon solar cells, and works well in bifacial applications, as well.
This ease of manufacturing has resulted in a sharp increase in PERC cell production since , and according to German mechanical engineering trade group VDMA, mono PERC and similar technologies accounted for over 60% of the global PV cell marketplace by as of .
Cons
The cons of PERC solar cells have largely been mitigated in recent years, but it is important to point out why PERC didn’t catch on in the ‘80s when it was first invented. Chief among the concerns with this technology is a problem called Light-Induced Degradation (LID), which occurs in all silicon solar cells, but can be especially pronounced in PERC cells.
LID occurs when boron from the positive silicon layer and oxygen mix, and usually results in a small, immediate reduction in power generation capability. This problem can be worse in PERC cells, which usually have extra boron, but all companies that produce and use PERC cells have come up with ways to fight it.
Another type of problem that can occur in all silicon solar cells is called Potential-Induced Degradation (PID), which can happen when a difference in potential energy exists between the cells and materials of a solar module and the ground.
It’s very complicated, but there is an international standard for module construction that manufacturers can follow, and all manufacturers worth their salt have implemented their own steps against PID.
Your best bet is to choose a high-quality solar module manufacturer and read about the steps they take to mitigate PID and LID.
Who makes PERC solar panels?
Many solar module manufacturers use PERC solar cells in some of their products. Among the best of these are:
Canadian Solar
Jinko Solar
Q CELLS
REC Solar
What are the alternatives to PERC technology?
PERC is one of the easiest and most cost-effective ways solar cell engineers have found to improve the efficiency and performance of solar cells.
As we discussed above, the technology does have its drawbacks, and overcoming them is not a trivial matter. PERC is also a relatively mature technology, and it can’t be used to push efficiency much higher than existing top-of-the-line cells.
That’s why many solar manufacturers are using alternatives to PERC that each have their own benefits and drawbacks. Here’s a quick rundown of other mainstream technologies currently used to increase solar cell efficiency: Tunnel Oxide Passivated Contact, heterojunction, and perovskites.
Tunnel Oxide Passivated Contact (TOPCon)
There’s that word “passivated” again. In fact, TOPCON technology is basically just the next generation of PERC, and like its forbear, it can be added to cells manufactured in the traditional way. TOPCon involves adding an ultra-thin layer of silicon dioxide (SiO2) and a layer of polycrystalline silicon doped with phosphorus.
Because TOPCon is the next logical step after PERC, it does not add a great deal of additional cost to the finished product. It can produce additional gains in efficiency over PERC, but its theoretical maximum efficiency is 23.7%. It’s important to note that modules manufactured with current TOPCon technology top out at around 23%, though.
Heterojunction (HJT)
Heterojunction solar cells are made of alternating layers of traditional crystalline silicon and amorphous silicon, the latter of which is normally associated with thin-film solar panels. By combining the two different kinds of layers, HJT cells absorb more wavelengths of light, and the different layers work together to make the cells the most efficient on the market today.
Unfortunately, HJT technology cannot be made in the same way traditional solar cells can, so it requires significant re-tooling and new industrial processes. This tends to make HJT solar modules quite expensive, although they do carry a reputation for premium quality and high performance.
HJT solar cells have a theoretical maximum efficiency of greater than 26.7%, but current offerings from companies like REC Solar and Panasonic top out around 24%.
Perovskites
Perhaps the most exciting and furthest-off technology to improve the efficiency of solar cells is called perovskites.
Perovskites are a class of materials that have a certain crystalline structure that makes it extremely easy to produce and carry electrical charges in photovoltaic applications. This characteristic means perovskite solar cells could eventually have a conversion efficiency as high as 38%.
Unfortunately, many naturally-occurring perovskites contain lead, which is toxic. Safe artificial perovskites have been created using tin, but they are very difficult to work with and degrade much faster than their lead-based cousins.
Oxford PV, the world’s leading perovskite solar cell manufacturer, has created “tandem cells” by embedding a layer of perovskites on top of traditional silicon solar cells. These cells set a world record for efficiency of 29.52% in December of . Oxford PV hopes to sell its products to the residential market starting in .
If they can pull it off at a reasonable price, they might make PERC, HJT, and all the other technologies seem like old news.
The final word on PERC
If you’re a homeowner in the USA who has been looking for quotes for solar, you’ll probably get at least one quote that includes PERC solar panels.
As we’ve discussed above, these panels are likely to be more efficient than traditional solar panels, which means they’ll produce more electricity in the same surface area. If maximizing your roof’s potential for energy generation is important to you, modern PERC solar panels from a top manufacturer will be one of your best option
Contact us to discuss your requirements of 10 Watt Solar Panel. Our experienced sales team can help you identify the options that best suit your needs.
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