Naked Science Forum

Non Life Sciences => Chemistry => Topic started by: ScientificSorcerer on 07/11/2013 00:11:50

Title: What makes phosphors glow?
Post by: ScientificSorcerer on 07/11/2013 00:11:50

     ~ Phosphors and Phosphorescence ~

                                          (https://www.thenakedscientists.com/forum/proxy.php?request=http%3A%2F%2Fupload.wikimedia.org%2Fwikipedia%2Fcommons%2F1%2F12%2FFluorescent_minerals_hg.jpg&hash=caca450210d0b0261be1f18c826bbd92)

I have recently been attempting to understand how certain chemicals glow in the dark, glow under UV light and glow when exited by electricity. I have had some success in understanding most of it but I can't seem to find out one thing. and that's the solid materials which glow when exited by electricity. From what I understand when an atom's electrons "discharge" after being electrified (jump down a power level) they emit a photon. I know that this is the mechanism behind neon and florescent lights.

But what I want to know is are there any solid materials (not gas) which glow when exited by electricity, I believe that such materials exist because the inside of cathode rays are coated in some kind of powder which glows when the electron beam hits it (electrically exiting the powder).

The reason why I want to know this is because I want to see if a current can be passed through the material to make it glow. and to see if my tesla coil can induce a current in the material through induction to make it glow. is that possible?

I really want to know what these materials are called and how they work so if any readers know what these types of materials are called or how they work your help and advice would be greatly appreciated.

Title: Re: phosphors!
Post by: evan_au on 07/11/2013 08:42:18

It is called electroluminescence (http://en.wikipedia.org/wiki/Electroluminescence).

Some types are semiconductors, operating from low-voltage DC.
Other types are insulating powders, activated by an AC supply. This type would be more suitable for activation by a Tesla coil - but the voltage may too high, and cause electrical breakdown of the panel.

A challenge with these displays is to provide an electrical supply (usually through a metal, usually reflective) while letting the light out (transparent). Materials like indium tin oxide can meet these apparently conflicting requirements, at least at low currents.

Title: Re: What makes phosphors glow?
Post by: ScientificSorcerer on 08/11/2013 08:11:11

Thank you evan_au you really helped me out, your statement gave me the right key words to continue my research into the field, your help is greatly appreciated.