An Enhanced Long Persistent Red Phosphor: CaS:Eu{sup}(2+),Tm{sup}(3+),Ce{sup}(3+)

摘要

Calcium sulfide singly and/or codoped with Eu{sup}(2+), Ce{sup}(3+) and Tm{sup}(3+) phosphors were prepared by using a solid state chemical reaction method. Emission and excitation spectra of the samples were investigated. CaS:Eu{sup}(2+) emission was found at 648nm and CaS:Ce{sup}(3+) emission was found at 515nm. CaS:Eu{sup}(2+),Tm{sup}(3+) was long persistent and the persistence time was～1 hour. By the doping Ce{sup}(3+), CaS:Eu{sup}(2+),Tm{sup}(3+),Ce{sup}(3+) persisted 22% longer than that of CaS:Eu{sup}(2+),Tm{sup}(3+). Strong energy transfer from Ce{sup}(3+) to Eu{sup}(2+) was found at a low doping concentration 0.1%. The brightness of Eu{sup}(2+) emission was enhanced for about 20% by codoping with Ce{sup}(3+).