Why is silicon used in solar cells?

Importance of solar energy


The use of solar energy is a trend rapidly gaining popularity in India as it is available in large quantities in most parts of the country. More importantly, it is a renewable energy source that never goes out. While solar energy is readily available, using this energy for practical purposes is a tricky business. However, past research has shown that it can harness it into electricity, and the current research aims to convert all received energy into valuable electricity.



What is a photovoltaic cell?


Solar energy conversion into electricity is accomplished using the principle of the photovoltaic (PV) effect. The photovoltaic effect is converting solar energy into electricity through photovoltaic cells made of semiconductors such as silicon. When sunlight hits a photovoltaic cell, its components called photons absorb the received light energy and transfer that energy to electrons in the semiconductor material, which then flows as an electrical current. This current becomes the source of electricity. One of the most popular semiconductor materials for photovoltaic cells is silicon, which has properties that help generate electricity from solar energy.

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What is a silicon solar panel?


Solar panels made of silicon semiconductors are called silicon solar panels. Many photovoltaic cells gathered in an airtight panel act as solar energy collectors. Silicon semiconductors are popular because of their low weight-to-volume ratio, extended life cycle, robustness, and strength. Silicon semiconductors are easy to produce at a low cost.

Silicon solar panels come in different sizes to suit various applications. Silicon solar panels typically include 32, 36, 48, 60, 72, and 96 PV cells. Several of these panels can be connected in series or parallel for higher power, suitable for applications with high power requirements.

Types of Silicon Solar Panels Basically, there are three types of silicon solar panels, mainly classified according to the type of photovoltaic cells. They can be divided into monocrystalline, polycrystalline, and amorphous or thin-film solar panels. Each of them has different characteristics that can affect the output of the electricity produced.



Monocrystalline Solar Panels


Monocrystalline solar panels are made from photovoltaic cells cut from silicon ingots grown from a single crystal of pure silicon. When the cylindrical ingot is sliced, its round shape is square, giving the cell its distinctive octagonal shape. This shape distinguishes cells from cells made of polysilicon. In addition, the monocrystalline solar cells have uniform black color in all cells. The PV cells in the panels provide a better collecting surface due to the pyramidal pattern of the crystals. With proper handling and the addition of other materials, these cells can last up to 30 years or more and are more efficient than the other two types of silicon solar panels. Monocrystalline solar panels have efficiencies between 15-20%, the highest silicon-based solar panels.





Polycrystalline Solar Panels


Polycrystalline solar panels are made from photovoltaic cells cut from multiple silicon crystals. Pour molten silicon into square molds. The silicon is cut into squares after cooling in the mold. The perfect square shape differentiates polycrystalline cells from monocrystalline cells (octagonal). These have the same properties as monocrystalline solar panels but are less efficient at converting solar energy into electricity. These cells are cheaper than monocrystalline cells because there is less silicon waste.



Thin Film or Amorphous Solar Panels


Thin-film or amorphous solar panels include a substrate on which a thin layer of amorphous silicon is deposited. These are becoming more popular due to their mass production capabilities and use where the surface area for deploying panels is not limited. Amorphous solar panels are inefficient and used in small applications such as pocket calculators. But with new "stacking" techniques, layers can be combined to increase efficiency (6-8%). Due to the flexibility of amorphous solar panels, we can also use them in innovative ways on curved surfaces.



Silicon Solar Panel Applications


Almost 90% of solar energy applications use silicon solar panels to generate electricity. The many applications of silicon solar panels are as follows: In power plants, silicon solar panels provide the necessary energy to boil water and generate steam that can spin turbines to generate electricity. They can replace other non-renewable energy sources. In homes, silicon solar panels placed on roofs can serve as stand-alone systems for heating household water. These panels can also be a source of free electricity if they charge rechargeable batteries, which can then use to power a home. In commercial establishments, as in homes, silicon solar panels placed on the roof or backyard can be used as primary or backup power. Stand-alone solar power systems use silicon solar panels to power water pumps to pump to fields or elevated tanks in fields or homes. In swimming pools, silicon solar panels keep the water in the pool hot during the winter. Stand-alone systems using silicon solar panels can power streets, sidewalks, walkways, or backyards for lighting applications. They can also be used as portable flashlights.