The main difference between fluorescence and phosphorescence is that fluorescence occurs and ceases rapidly, whereas phosphorescence takes longer to glow and slowly ceases after removal of the source.

Fluorescence vs Phosphorescence

When an atom or a molecule absorbs energy, it becomes excited which is of high energy and unstable state. As we know, each atom or molecule wants to be stable, so it emits energy in the form of radiation or photons to return to its fundamental state that makes the element glow, which is known as photoluminescence. There are two types of photoluminescence, that is, fluorescence and phosphorescence. In both types, the energy of the emitted photons is less than that of the absorbed photons and the emission has a longer wavelength than the incident light. But they differ in the duration of the process. Fluorescence occurs much faster than phosphorescence. It occurs rapidly and ceases rapidly after removal from the source. Moreover, during phosphorescence, The emission of radiation takes a long time to start and remains for some time even after the source is removed. So the time period between emission and absorption of energy is short in fluorescence but comparatively long in phosphorescence. In fluorescence, the absorption process changes the transition from the ground to the excited singlet state without changing the direction of the spin. On the other hand, during the phosphorescence absorption process involves the transition from the state of to the excited triplet and also changes the direction of the spin. The fluorescence of gemstones, including talc, gypsum, vitamins, chlorophyll extract and jellyfish, etc., are examples of fluorescence, while the glow from toys, watches, etc., after turning off the light in the room, are examples of phosphorescence. the time period between emission and absorption of energy is short in fluorescence but comparatively long in phosphorescence. In fluorescence, the absorption process changes the transition from the ground to the excited singlet state without changing the direction of the spin. On the other hand, during the phosphorescence absorption process involves the transition from the state of to the excited triplet and also changes the direction of the spin. The fluorescence of gemstones, including talc, gypsum, vitamins, chlorophyll extract and Jellyfish, etc., are examples of fluorescence, while the glow from toys, watches, etc., after turning off the light in the room, are examples of phosphorescence. the time period between emission and absorption of energy is short in fluorescence but comparatively long in phosphorescence. In fluorescence, the absorption process changes the transition from the ground to the excited singlet state without changing the direction of the spin. On the other hand, during the phosphorescence absorption process involves the transition from the state of to the excited triplet and also changes the direction of the spin. The fluorescence of gemstones, including talc, gypsum, vitamins, chlorophyll extract and Jellyfish, etc., are examples of fluorescence, while the glow from toys, watches, etc., after turning off the light in the room, are examples of phosphorescence. The absorption process changes the transition from the ground to the excited singlet state without changing the direction of rotation. On the other hand, during the phosphorescence absorption process involves the transition from the state of to the excited triplet and also changes the direction of the spin. The fluorescence of gemstones, including talc, gypsum, vitamins, chlorophyll extract and Jellyfish, etc., are examples of fluorescence, while the glow from toys, watches, etc., after turning off the light in the room, are examples of phosphorescence. The absorption process changes the transition from the ground to the excited singlet state without changing the direction of rotation. On the other hand, during the phosphorescence absorption process involves the transition from the state of to the excited triplet and also changes the direction of the spin.Fluorescence of gemstones, including talc, gypsum, vitamins,

Comparative chart

What is fluorescence?

Fluorescence occurs when electrons travel from their low-energy ground state to a high-energy excited state. These electrons keep their spin the same as in the ground state, but when they emit energy when they return to the ground state. This energy has a longer wavelength than that absorbed. We can see bright light if this longest wavelength is within the visible spectrum. The time interval between absorption and emission of energy is very short and, suddenly, emission ceases by eliminating the excitation source.

What is phosphorescence?

Phosphorescence is like fluorescence, but the spin changes when the electron goes into the excited state. Electrons rotate in a specific direction based on magnetic moment. When a compound shows phosphorescence, its electron has received enough additional energy to change the direction of the spin. This change in a spin makes the emission live for a long time because it takes longer for the electron to release all its energy.

Key differences

1. A type of photoluminescence in which the absorption of energy by an atom or molecule is followed by a rapid release of energy is known as fluorescence, while a type of photoluminescence in which the absorption of energy by an atom or molecule is followed by a slow release of energy is known as phosphorescence.
2. During fluorescence, the emission of energy or light ceases suddenly upon removal of the excitation source, on the other hand, the emission of energy or light remains for some time in phosphorescence even after removal of the excitation source.
3. The excited atom has a short life in fluorescence before its transition to the low energy state, on the contrary, the excited atom has a long life in phosphorescence before its transition to the low energy state.
4. The time interval between absorption and emission of radiation is very short in fluorescence on the other hand; the time interval between absorption and emission of phosphorescent radiation is comparatively long.
5. The absorption process during fluorescence changes the transition from the ground state to the excited singlet state, whereas in the absorption process by phosphorescence it involves the transition from the ground state to the excited triplet state.
6. The direction of rotation does not change during fluorescence; on the other hand, phosphorescence changes the direction of rotation.
7. During fluorescence, the emission has a longer wavelength than incident light, whereas in phosphorescence, the emission has a longer wavelength than fluorescence.
8. A fluorescent material provides immediate flash or post-excitation glow on the other side; a phosphorescent material appears to glow in the dark.
9. Gemstone fluorescence, including talcum, gypsum, vitamins, chlorophyll extract and jellyfish, etc., are examples of fluorescence while, the glow of toys and clock dials after turning off the light in the room and the sign that lights up at night, etc. are the examples of phosphorescence.

Final Thought

The above discussion summarizes that fluorescence and phosphorescence are the two types of photoluminescence. Fluorescence does not change the spin of electrons and occurs and stops rapidly, while phosphorescence changes the spin of electrons and takes time to occur and stop.