rf magnetron-sputter-deposited ZnS:TbOF thin-film electroluminescent (EL) phosphors 1 mum +/- 10% thick were codoped with Ag, Cu, Ag+Cu, and Ce and tested with 60 Hz. trapezoidal voltage pulses. After annealing at 500 degreesC for 60 min, the EL brightness at 20 V above threshold, B-20, for Cu+Ag codoped ZnS:TbOF film was 67 cd/m(2) compared to 55 cd/m(2) for undoped ZnS:TbOF films. The B-40 of Ce codoped ZnS:TbOF films annealed at the same conditions was 144 cd/m(2) compared to 86 cd/m(2) for undoped ZnS:TbOF films. While the brightness increase of Cu+Ag codoped ZnS:TbOF film is attributed to improve crystallinity and increased surface roughness, the increase due to Ce codoping of ZnS:TbOF film is more likely, due to modified space charge in the ZnS:TbOF film.