How a Photovoltaic Cell WorksThanks to the boundless supply of sunshine in Central Arizona, installing solar panels can significantly reduce your electricity bills. You’ve surely seen these rectangular glass panels on roofs around town, but have you ever stopped to think how they work?

Unlike solar water heaters, which transfer the sunlight’s energy as heat, solar panels work through the interaction of sunlight with semiconductor materials in a photovoltaic cell to create electricity. Each panel is made up of many of these individual cells. Each cell is a sandwich of glass, two types of semiconductor and positive/negative terminals that ultimately collect and transport the electricity into your home.

Photons are the fundamental particle of electromagnetic energy. We see them as light. These massless particles travel from the sun at the speed of light. If they happen to hit a photovoltaic cell, this is what happens:

  • First, the photon travels through the protective layer of transparent glass. Not all photons make it through. Depending on the wavelength of the photon and the materials used in the photovoltaic cell, they might be reflected back into space.
  • The photon reaches the first semiconductor. It’s called the n-type layer because it has an abundance of negatively charged electrons in it.
  • The photon excites these electrons, which causes them to pass through the junction separating the n-type layer of semiconductor from the p-type (for positive) layer.
  • The p-type layer has an abundance of electron holes, which are the opposite of electrons.
  • The excited electrons from the n-type layer travel to the p-type layer (as the holes move the opposite direction) by the electromotive force.
  • Some of these electrons pass through to the positive/negative terminals on either side of the cell – which, after inverting, is the electricity you can use in your home.
In simpler terms, for those who missed physics class: energy from the sun excites the atoms in the photovoltaic cell, which in turn makes usable electric current.For more information on how solar power can reduce your electricity bill in the greater Phoenix area, contact Wolff Mechanical. With 20 years of experience, we know the answers.

Our goal is to help educate our customers in the Phoenix Valley area of Arizona about energy and home comfort issues (specific to HVAC systems). 

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