Article: Silicon: The Essential Element of Modern Solar Panels

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Le silicium : L'élément essentiel des panneaux solaires modernes - Oscaro Power

Jul 20, 2023Technologie

Silicon: The Essential Element of Modern Solar Panels

In our quest for a cleaner and more sustainable energy transition, solar panels have emerged as an essential solution. At the heart of this technology is a key element: silicon . You may have heard of its importance, but what is silicon exactly and why is it so essential in the manufacturing of solar panels modern? In this article, we will explore this central question in detail.

We will dive into the details of extraction , purification and of the transformation of silicon into solar cells 🌞 . We will also examine the specific advantages of silicon, such as its high energy efficiency, durability and affordability, which make it the standard in the solar industry.

What is silicon?

Definition and characteristics of silicon

Silicon is a chemical element used in the solar panel industry due to its unique properties as a semiconductor. It is widely distributed in nature 🌳, present in the Earth's crust as silica , and it is extracted and purified for use in the manufacture of solar cells.

Silicon, whose symbol is Si, is a dark gray crystalline semiconductor . It is the second most abundant element in the Earth's crust , after oxygen. Its crystalline structure gives it unique electrical properties, making it the material of choice for photovoltaic applications.

Abundance and availability of silicon in nature

Silicon is extremely abundant in nature, making up about 28% of the Earth's crust. It is mainly present in the form of silica (silicon dioxide), which is found in the sand, quartz and various minerals . This abundance makes silicon easily accessible and economically viable for the solar industry.

Physical and chemical properties of silicon

Silicon has properties physical and chemical which make it ideal for the conversion of solar energy into electricity . It is a semiconductor , meaning that it is an insulator in its pure state. However, by introducing specific impurities, it can be made conductive when placed under specific excitation conditions. Silicon is also characterized by its chemical stability, corrosion resistance, and durability. It can withstand high temperatures 🌡️ and varied environmental conditions , making it a reliable material suitable for long-term solar applications.

Silicon in solar panels

Silicon is the basic material used in the manufacture of most solar cells , also called photovoltaic cells . Which are then assembled in series/parallel and encapsulated in a protective plastic material to form solar panels. Its use in this industry is based on its semiconducting properties and its ability to generate electricity from sunlight. ☀️

Functionalization of silicon used in solar cells

These photovoltaic cells are made from thin slices of monocrystalline or polycrystalline silicon. The silicon , natively insulating, is rendered active, and therefore conductor in the presence of the light spectrum of the sun , by doping on the 2 faces of the cell . One is n-doped (for negative) by the addition of phosphorus atoms in the crystalline structure of silicon, the other doped p (for positive) by the addition of boron atoms.

THE Silicon solar cells are therefore composed of a thin wafer (of the order of 180 microns) of monocrystalline silicon whose 2 faces have been doped and then on the upper part an anti-reflective layer is also deposited in order to maximize the absorption of solar light.

Difference between monocrystalline, polycrystalline and amorphous silicon

THE Monocrystalline silicon is composed of a single crystal of silicon , which gives it a uniform structure and a high energy efficiency . It is obtained by melting pure silicon and slowly cooling it to form a single crystal. Monocrystalline silicon solar cells are generally more expensive , but they offer a higher efficiency , making them ideal for installations where space is limited.

THE Polycrystalline silicon is made up of several small silicon crystals , which gives it a shimmering appearance. It is obtained by melting pure silicon with doping materials and then allowing it to cool rapidly, thus the productivity of the process is higher. Silicon solar cells Polycrystalline silicon panels are cheaper to produce than monocrystalline silicon panels, but they have slightly lower efficiency . The production of polycrystalline silicon panels is becoming increasingly marginal.

THE amorphous silicon is a non-crystalline material which does not have a regular structure. It is made by depositing silicon on a substrate at relatively low temperatures. Amorphous silicon solar cells are flexible and can be used in applications where flexibility and light weight are important, but they have lower efficiency than crystalline silicon cells.

Manufacturing process of silicon solar panels

Step 1: Extraction and purification of silicon

Silicon is extracted from silica present in sand ⏳ or quartz. It then undergoes a purification process to remove impurities and obtain high purity silicon necessary for the manufacture of solar cells.

Step 2: Formation of silicon ingots

THE silicon is purified, usually by chemical process. This silicon purified is then melted at temperatures above 1400C. 🥵

In the case of the polycrystalline silicon cell manufacturing process, molten silicon is poured into molds to form large parallelepiped blocks which will be cut into smaller blocks called ingots.

In the case of the manufacturing process of cells based on monocrystalline silicon (most common) , a single crystal of silicon is drawn from the molten silicon bath in the form of a bar with a circular section and a diameter of around twenty centimetres. Once cooled, these large bars are also cut into parallelepiped-shaped ingots.

Step 3: Cutting the ingots into thin slices (wafers)

The ingots are then cut into thin slices, called wafers, approximately 180 to 200 micrometers thick using a diamond wire.

Step 4: Functionalization of silicon wafers into photovoltaic cells

The wafers are textured by chemical treatment so that the surface catches the light. They are then treated with dopants to create a pn junction. This is the stage where a photovoltaic cell is obtained. able to deliver a current when exposed to sunlight. ☀️

Step 5: Assembling the solar cells and manufacturing the panels

THE Solar cells are assembled in series and parallel to form cell ribbons , which are then encapsulated in protective materials such as ethylene vinyl acetate (EVA) and glass to protect them from mechanical or chemical attack.

A box with an electronic component called a diode, which prevents the current from flowing in the opposite direction in the panel, is added as well as cables and connectors. We are then in the presence of a solar panel.

The advantages of silicon in solar panels

Silicon has many advantages for the manufacture of solar panels, making it a preferred choice for converting solar energy into electricity. ⚡️

Energy efficiency

High efficiency of silicon solar cells : Silicon solar cells offer high efficiency in converting solar energy into electricity. They are able to capture and convert a large amount of sunlight due to the electrical properties of silicon and the adaptation of the semiconducting character of silicon to the frequency band of the solar spectrum.

Want to know how solar energy is an inexhaustible resource? Let yourself be tempted by reading our article on the subject.

Recent improvements in silicon technology : Continuous advances are being made in silicon technology, which is helping to improve the efficiency of solar cells. Techniques such as selective doping, back-passivated contacts, and more sophisticated cell structures are helping to increase the overall efficiency of silicon solar panels. Cells currently on the market have efficiencies of around 21%. while the theoretical maximum yield for the silicon material is 28% . (for a solar irradiation of 1000Wm² at midday, a solar panel can therefore collect up to 210W/m².) In terms of orientation value, we can say that a current solar panel has a peak power in standard laboratory conditions of 400W on a surface area of around 2m²).

Durability and reliability

Long life of silicon solar panels : Silicon solar panels are renowned for their long-term durability. They can operate efficiently for several decades with minimal maintenance. This makes them a cost-effective and sustainable investment for solar energy production.

Resistance to weather and environmental conditions : Silicon is a stable and durable material. Silicon solar panels are designed to withstand harsh environmental conditions, including temperature fluctuations, high winds, harsh weather, freezing temperatures, and corrosion. They are often certified for their resistance to extreme weather conditions.

Cost and accessibility

Abundant availability of silicon : Silicon is one of the most abundant materials on Earth 🌍. Its widespread availability makes it an economically viable and environmentally sustainable choice for manufacturing solar panels. The growing demand for solar energy has also led to an increase in silicon production, which has contributed to lower costs.

Reduced manufacturing and installation costs : Over the years, the manufacturing costs of silicon solar panels have decreased significantly thanks to technological advances and optimization of production processes. This has made solar energy more accessible and competitive compared to other energy sources.

In conclusion, silicon is a essential material used in the solar panel industry due to its unique properties as a semiconductor. It offers high energy efficiency, long-term durability and abundant availability, making it an ideal choice for solar power generation.

In the context of the Oscaro Power's quality solar panels , silicon plays a key role in the manufacturing of their premium products. By using high-quality silicon and focusing on technological innovation, Oscaro Power selects reliable, high-performance and durable solar panels.

By investing in quality solar panels like those offered by Oscaro Power, users can enjoy the benefits of silicon, including high energy efficiency, long-term durability and a positive contribution to the environment. These solar panels are an eco-responsible solution for greener and more sustainable energy production.

In short, Oscaro Power’s silicon and quality solar panels are a winning combination for those looking to harness solar energy efficiently, reliably and in an environmentally friendly manner. It is through continued advances in the solar industry and innovative solutions like those offered by Oscaro Power that we can look forward to a more sustainable and energy-responsible future.

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