You’ve likely heard of photovoltaic (PV) solar panels. But do you really know how photovoltaics work? Just how do those blue-colored surfaces convert sunlight into electricity? In other words, how do we tap into solar energy?
PV technology was “born” in 1854 through research of the Bell Telephone Company. Within a decade PV solar panels were being used on spacecraft. It wasn’t long before property owners in remote areas determined that they did not have to be connected to the grid in order to enjoy electricity – with installation of PV panels. From there, even grid-connected customers have decided to minimize or eliminate their monthly electricity bills by going solar.
So, let’s review how photovoltaics work!
PV solar cells convert UV light photons into electricity. Photovoltaics do this through two distinct functions. First, there is photogeneration of charge carriers (electrons and holes) in a light-absorbing material. Then, separation of the charge carriers to a conductive contact to transmit the electricity.
The following video is a good primer of how photovoltaics work:
The word “photovoltaic” is derived from “photo,” which means “light” and “voltaic” which means “electricity. A solar module is a group of cells connected electrically and packaged into a frame (commonly known as a solar panel) A number of solar panels grouped together is a solar array.
PV solar cells are made of semiconductor materials, like silicon, used most commonly these days. When sunlight hits a solar cell, some of the energy is absorbed by the semiconductor material; energy knocks electrons loose and they can then freely flow.
The electric field(s) of PV solar cells can force the freed electrons to flow in a certain direction. This flow is an electrical current. With metal contacts on the top and bottom of a PV cell, the current can be drawn away for power usage.
No matter how large or small it is, most silicon PV cells produce about 1/2 volt direct current (under open-circuit, no-load conditions). The output of a PV cell depends on its efficiency and size (surface area), and is proportional to the intensity of sunlight striking the surface of the cell.
While there are a number of factors that contribute to the amount of electricity that can be generated by a solar cell, a general understanding of how photovoltaics work is important in determining whether and how much to invest in a solar array.