Fluorescent Materials

Mrs. L. Fox

What is Fluorescence?

• The emission of electromagnetic radiation, especially of visible light, stimulated in a substance by the absorption of incident radiation and persisting only as long as the stimulating radiation is continued.

Fluorescent Lamps

• A fluorescent lamp converts electrical power into useful light more efficiently than an incandescent lamp.

• Lower energy cost typically offsets the higher initial cost of the lamp.

• They are also cooler than incandescent lights

Other Types of Fluorescent Lights

How Does This Type of Light Differ From Regular Light Bulbs?

• The main difference between these sources is the process of exciting the atoms.

• In an incandescent light source, such as an ordinary light bulb or gas lamp, atoms are excited by heat; in a light stick, atoms are excited by a chemical reaction.

Other Things That Glow

• Fluorescent molecules tend to have rigid structures and delocalized electrons. Examples of common materials that MIGHT contain fluorescent molecules include:

• White Paper • Petroleum Jelly• US $20 Bill

Modern US $20 bills contain a security strip near one edge that glows bright green under a black light.

• Tonic Water

• Body Fluids• Vitamins• Chlorophyll• Antifreeze• Laundry Detergents

Tooth Whiteners

• JellyfishSome Minerals and GemsBanana Spots

Phosphorescence

• Is a specific type of photoluminescence related to fluorescence.

• It releases the radiation more slowly• Example include:– glow-in-the-dark toys– Paint– clock dials

Triboluminescence

• Is an optical phenomenon in which light is generated through the breaking of chemical bonds in a material when it is pulled apart, ripped, scratched, crushed, or rubbed

• Examples:– Wintergreen candy– Ripping apart adhesive tapes

Chemiluminescence

• Is the emission of light (luminescence), as the result of a chemical reaction.

• There may also be limited emission of heat.

Bioluminescence

• That light that is emitted from living (or once living) organisms.

• This is a type of chemiluminescence.– Examples:• Jellyfish• Some algae (diatoms)• Fluorescent fish