I noticed this technology that appeared online regarding Tritium lamps. Now Tritium lamps would actually work off of phosphorous I think or some excitation of another gas by the Tritium radioactivity. Here is an interesting sight for lamps that are active for 25 years they say.
Tritium Light Source - Green - $49.00 : United Nuclear , Scientific Equipment & Supplies, United Nuclear , Scientific Equipment & Supplies
Tritium Light Source - Green - $49.00 : United Nuclear , Scientific Equipment & Supplies, United Nuclear , Scientific Equipment & Supplies