The solar energy industry has witnessed remarkable advancements in photovoltaic (PV) technology over the years. One of the most promising innovations is Tunnel Oxide Passivated Contact (TOPCon) technology. This cutting-edge technology is revolutionizing the efficiency and performance of solar cells, making them a preferred choice for residential, commercial, and industrial applications.
TOPCon solar cells are an evolution of the widely used Passivated Emitter and Rear Contact (PERC) technology. With superior passivation and improved electron flow, TOPCon technology enhances energy conversion efficiency while reducing losses, positioning itself as the next-generation PV technology.
Table of Contents
In this comprehensive guide, we will explore TOPCon technology, its benefits, working principles, comparison with other technologies, market trends, and future prospects.
What is TOPCon Technology?
TOPCon, short for Tunnel Oxide Passivated Contact, is an advanced solar cell architecture that enhances efficiency and energy yield over conventional solar cells. As the name suggests, TOPCon cells use a thin, passivating tunnel oxide layer that enables excellent carrier selectivity and low contact resistance, allowing more sunlight to be converted into electricity.
In simple terms, TOPCon technology combines the best benefits of older cell technologies like PERC (Passivated Emitter and Rear Cell) and heterojunction cells into one single architecture while avoiding their drawbacks. As a result, TOPCon delivers superior efficiency of over 22%, compared to around 18–19% for PERC cells currently.
Key Features of TOPCon Technology:
1. Tunnel Oxide Layer: The tunnel oxide layer in TOPCon (Tunnel Oxide Passivated Contact) solar cells is a thin layer of silicon oxide that passivates the silicon surface. This layer is a key component of the cell’s structure, which improves efficiency and performance.
2. Poly-Silicon Contact: Poly-silicon contact TOPCon technology, or Tunnel Oxide Passivated Contact technology, is a solar cell technology that uses a polycrystalline silicon layer to improve the efficiency of solar cells.
3. Higher Efficiency: TOPCon panels can achieve efficiency rates of over 22%, which is higher than traditional solar cells.
4. Superior Passivation: Superior passivation TOPCon technology is a solar cell technology that uses a thin layer of silicon dioxide to improve the performance and efficiency of solar cells.
5. Bifacial Benefits: Bifacial solar panels with TOPCon technology are more efficient than traditional solar panels and can generate more electricity. They are especially useful in areas with low sunlight, such as cloudy days or areas with vegetation.

How TOPCon Technology Works
TOPCon (Tunnel Oxide Passivated Contact) technology is an advanced solar cell architecture designed to enhance the efficiency and performance of photovoltaic systems. It achieves this by incorporating a thin tunnel oxide layer and a polycrystalline silicon layer to form a passivated contact on the rear side of the cell.
How do TOPCon solar cells work?
Tunnel Oxide Passivated Contact, or TOPCon for short, refers to a certain solar cell construction. Even after researchers at Freiburg’s Fraunhofer Institute for Solar Energy Systems introduced the new cell architecture in 2013, it took several years for the first TOPCon modules to be sold.
The fundamental tenet of the TOPCon concept is that the silicon layer is not in contact with the metal of the connection contacts. Charge carrier recombination, which usually results in performance losses at the back of the cell, is avoided as a result.
A thin layer of silicon oxide (a few nanometers thick) is applied to the solar cell’s surface to prevent recombination. This layer passivates the surface, meaning it prevents a certain kind of charge carrier from passing through, but it is so thin that the current can “tunnel through” it quantum mechanically. In addition to this “tunnel layer,” a layer of highly doped silicon is added to increase electrical conductivity and lower transmission losses.
Benefits of TOPCon Technology
1. Higher Efficiency Levels
The mass production efficiency of TOPCon has reached up to 25.2%, surpassing the mainstream PERC’s 23.2% by 2 percentage points. Projections indicate that TOPCon’s efficiency could soar to 26.8% by the second half of 2023, widening the efficiency gap with PERC to 3.3 percentage points.
2. Low Degradation Rate
The N-type battery’s wafer substrate, doped with phosphorus, nearly eliminates photoluminescence attenuation due to the absence of boron-oxygen pairs. The first-year attenuation rate of TOPCon modules is about 1%, compared to PERC’s 2%, with an average annual attenuation rate post-first year of about 0.4% (vs. PERC’s 0.45%).
3. Low Temperature Coefficient
TOPCon modules excel in high-temperature environments, with a power temperature coefficient as low as -0.30%/°C, compared to PERC modules’ -0.34%/°C.
4. High Bifacial Rate
The bifacial rate of TOPCon can reach over 80%, significantly higher than PERC’s 70%. This attribute is particularly advantageous in large base projects with high ground reflectivity, enhancing power generation efficiency.
5. Environmental Impact
Investing in TOPCon solar panels contributes to a cleaner environment by reducing dependence on fossil fuels. Solar energy is renewable and produces no greenhouse gas emissions during operation. By choosing TOPCon technology, you are not only saving on energy costs but also making a positive impact on the planet.
6. Installation and Maintenance
The installation process for TOPCon solar panels is similar to traditional solar panels. It typically involves mounting the panels on your roof or in your yard, connecting them to an inverter, and integrating them with your home’s electrical system. Regular maintenance is minimal, usually requiring only occasional cleaning to ensure optimal performance.

TOPCon Technology vs. Other Solar Cell Technologies
1. TOPCon vs. PERC Technology
Feature | TOPCon | PERC |
---|---|---|
Efficiency | >24% | 21-23% |
Passivation | Superior | Standard |
Bifacial Performance | Yes | Limited |
Cost | Slightly higher | Lower |
Degradation Resistance | High | Moderate |
2. TOPCon vs. Heterojunction (HJT) Technology
Feature | TOPCon | HJT |
Efficiency | High (>24%) | Very High (>26%) |
Manufacturing Complexity | Moderate | High |
Cost | Lower than HJT | Higher |
Temperature Coefficient | Low | Lowest |
Current Market Trends in TOPCon Technology
The Tunnel Oxide Passivated Contact (TOPCon) technology has emerged as a leading advancement in photovoltaic (PV) cells, significantly enhancing solar panel efficiency and performance. Recent market trends indicate a robust and accelerating adoption of TOPCon technology across the global solar industry.
Market Growth and Projections
- Market Share Expansion: TOPCon technology is poised for substantial growth, with forecasts suggesting it could capture over 84% of the global market by 2029. This anticipated increase is attributed to its superior efficiency and adaptability, which are expected to drive down production costs and expand its market presence.
- Market Size Increase: The global TOPCon solar cell market is projected to grow from USD 8.58 billion in 2023 to USD 51.60 billion by 2033, reflecting a compound annual growth rate (CAGR) of 19.65%.
Technological Advancements
- Enhanced Efficiency: Manufacturers are achieving record-breaking efficiency rates with TOPCon solar panels, surpassing 24% in 2024. This improvement signifies a shift towards more energy-independent households and businesses, making solar power more accessible and practical for a broader range of applications.
- Integration with Building Materials: There is a growing trend of integrating TOPCon solar panels with building materials, such as roofing tiles, glass, and facade materials. This integration enhances the aesthetic appeal of solar installations and opens new avenues for solar energy harvesting, turning entire buildings into power generators without compromising design integrity.
Regional Developments
- Emerging Markets Expansion: Countries in Africa, Asia, and Latin America are experiencing a solar boom, driven by decreasing costs, government incentives, and the urgent need for sustainable energy solutions. This expansion is democratizing access to solar energy, contributing to global energy equity, and fostering economic development in underserved regions.
Industry Dynamics
- Patent Infringement Investigations: First Solar, a leading U.S. solar company, announced investigations into potential patent infringements related to TOPCon technology by various rival manufacturers. This development highlights the competitive landscape and the importance of intellectual property in the solar industry.
Conclusion
The future of TOPCon (Tunnel Oxide Passivated Contact) technology is incredibly promising. With its high efficiency, sustainability benefits, and ability to drive down production costs, TOPCon is set to revolutionize the solar energy industry. As the global shift towards clean energy continues, TOPCon’s role in this transition will only grow stronger, offering both economic and environmental advantages.
As it leads the way with superior performance, extended lifespan, and integration opportunities, TOPCon technology is a key player in shaping the future of solar energy.
Join the renewable energy revolution today! Whether you’re looking to invest in high-efficiency solar panels for your home or business or are simply interested in learning more about cutting-edge developments in solar technology, Soleos Solar is here to help. Reach out now to explore the potential of TOPCon technology and start your journey toward a more sustainable future!
Contact us at Soleos Solar to learn more and take the first step toward harnessing the power of the sun!