What is the Difference Between Fluorescence and Luminescence?

Fluorescence and luminescence are two forms of photoluminescence, which is the emission of light when a substance absorbs light energy. The main differences between fluorescence and luminescence are:

• Timescale: In fluorescence, the absorption and emission of light occur almost immediately, with a very short lifetime of the excited state (10⁻⁹ to 10⁻⁶ seconds). In luminescence, the emission of light can vary in duration, and it does not necessarily have to be immediate.
• Energy: Fluorescence always involves light energy, while luminescence can involve either light or heat energy.
• Definition: Fluorescence is the absorption of energy by atoms or molecules followed by the emission of light, while luminescence is a spontaneous emission of light by a substance not resulting from heat.

In summary, fluorescence is a rapid process where light energy is absorbed and immediately re-emitted, while luminescence is a broader term that encompasses the emission of light without heat and can have varying timescales for the emission process.

Comparative Table: Fluorescence vs Luminescence

Here is a table comparing the differences between fluorescence and luminescence:

In summary, fluorescence is a type of luminescence where a substance immediately reemits absorbed radiation, while luminescence involves the emission of light from a non-heated substance due to other causes, such as chemical or electrical energy.