Electroluminescence in thin-film CaS:Ce

Abstract

We report a double insulated CaS:Ce thin-film electroluminescent (EL) device which emits a bright green EL due to Ce 3 + luminescent centers, being characteristic of parity allowed 5d-4f transitions. A brightness level of 500 cd/m2 and emission efficiency of 0.11 Im/W have been obtained under 5-kHz sinusoidal voltage excitation. The CaS:Ce thin film has been fabricated by coevaporation of CaS and sulfur.

Luminescence in Sulfides: A Rich History and a Bright Future

“…In the middle of the 1980s it became clear that rare earth doping of ZnS would not lead to sufficiently bright EL materials. As a result, several new activator-host combinations were tested and found to yield bright emission, CaS:Ce (green) [ 56 ], SrS:Ce (blue-green) [ 57 ], CaS:Eu (red) [ 58 ] and SrS:Eu (orange) [ 59 ] being the most successful combinations. In these phosphors, the luminescent ions are Eu 2+ and Ce 3+ .…”

Optical properties of Ce3+-doped KLuS2 phosphor

“…It was also showed that CaS:Eu 2 þ , Tm 3 þ , Ce 3 þ can be used as an enhanced long persistent red phosphor [6] with a strong energy transfer from Ce 3 þ to Eu 2 þ found at a low doping concentration. A double insulated CaS:Ce thin-film electroluminescent (EL) device emitting a bright green EL due to the Ce 3 þ luminescent centre has been reported [7]. SrS doped by Ce 3 þ and co-doped by Pb 2 þ or Cl À , Na þ also gained attention mainly due to possibility of being used as thin films in electroluminescence devices [8][9][10].…”

Microstructure and characterization of electron-trapping stimulable phosphor SrS:(Eu,Sm) thin film on glass

“…13 The addition of sulfur results in increased crystallite size and reduced stress. The thermal coefficient of the phosphor film is larger than that of the glass substrate; i.e., tensile stress in the film is expected upon cooling from the deposition temperature.…”