Flourescent lights are what actually make plasma screens work.
"The central element in a fluorescent light is a plasma, a gas made up of free-flowing ions (electrically charged atoms) and electrons, Xenon and neon atoms, the atoms used in plasma screens, release light photons when they are excited.
Every pixel is made up of three separate subpixel cells, each with different colored phosphors. One subpixel has a red light phosphor, one subpixel has a green light phosphor and one subpixel has a blue light phosphor. These colors blend together to create the overall color of the pixel.By varying the pulses of current flowing through the different cells, the control system can increase or decrease the intensity of each subpixel color to create hundreds of different combinations of red, green and blue. In this way, the control system can produce colors across the entire spectrum.
The main advantage of plasma display technology is that you can produce a very wide screen using extremely thin materials. And because each pixel is lit individually, the image is very bright and looks good from almost every angle." (Harris, 2011)
Harris, Tom (2011)
How Plasma Displays Work