Y2O2S luminophors doped with Er3+ and Yb3+ ions are produced by means of solid-phase synthesis and deposited onto standard AL123A infrared light-emitting diodes. When excited with 940 nm radiation from a lioht-emittin-diode, the structures exhibit intense visible up-conversion luminescence. A maximal brightness of 2340 cd/m(2) of green and red up-conversion luminescence at corresponding wavelengths around 550 and 600 nm is observed for the Y2O2S compound doped with 2 at % Er3+ ions and 6 at % Yb3+ ions. The ratio of the intensity of green (or red) up-conversion luminescence to the intensity of infrared Stokes luminescence increases with increasing applied voltage. The efficiency of visible emission of the light-emitting diode structures is eta = 1.2 lm/W at an applied voltage of 1.5 V.