There is much glow in the dark products in the market nowadays, from mobile phone covers to toys. If you have seen any of these products, you know that they all have to be “charged”. You hold them up to a light for a few minutes, and then take them to a dark place where they glow for several hours.
All glow in the dark products contains phosphors. A phosphor is a substance that radiates visible light after being energized. The two places where we most commonly see phosphors are on a TV screen or computer monitor and in fluorescent lights. In a TV screen, an electron beam strikes the phosphor to energize it. In a fluorescent light, ultraviolet light energizes the phosphor. In both cases, what we see is visible light.