HOW SOLAR PANELS CONVERT SUNLIGHT INTO ELECTRICITY

THE ROLE OF THE PHOTOELECTRIC EFFECT AND SILICON

One of the fundamental concepts that enable the conversion of solar energy to electricity is the photoelectric effect. Essentially, when light with solar energy above a certain threshold hits the surface of a metal, electrons that were previously bonded to the metal are knocked out. Electrons can be ejected from the metal because sunlight is composed of particles called photons, and each photon collides with an electron and uses some of its energy to dislodge it from the metal.

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While the photoelectric effect ensures that solar energy can be used to excite and dispel loose electrons in metals, solar panels must also have the ability to keep these stray electrons together by herding them into an electric current. To do this, scientists create an electrical imbalance by utilizing semiconductors such as silicon within solar cells to ensure that electrons will all flow in the same direction.  In particular, silicon infused with small quantities of other elements is used because these impurities create two different types of silicon essential to generating a current. Silicon bonded to elements that have one more valence electron is referred to as n-type silicon, while silicon bonded to elements that have one less valence electron is referred to as p-type silicon.  When these two types of silicon are placed side by side within a solar cell, the spare electrons found in the n-type silicon move to fill gaps in the p-type silicon, making the n-type silicon positively charged and the p-type silicon negatively charged. This difference in charge across the solar cell helps generate an electric field, which is responsible for positioning the electrons in ways that ensure they will flow together as an electric current. After a current is created, electricity can be transported effectively to areas that need it. 

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Watch this video to learn more: https://www.youtube.com/watch?v=L_q6LRgKpTw