heres some info on what you're after:
In reply to:
Today, the most common luminescent product is Indiglo Night-light by Timex. This is a very safe method of lighting a watch dial. A watch battery supplies the energy to keep the dial lit. The substance used in Indiglo night-light is a mixture of ZnS and copper. A microchip converts an electrical charge from the watch battery to a higher voltage. This voltage is applied to the ZnS-Cu mixture, exciting the electrons. This microchip induces an alternating current that essentially turns the voltage on and off, allowing the electrons to return to the ground state. As electrons return to the ground state, energy is released in the form of light.
So Indiglo is the product you're after - and its pretty nice looking light, but it needs a microprocessor or electronics to drive it. and the voltage may be higher than 5v