10.1007/s11453-008-3022-5

Abstract

Y 2 O 2 S luminophors doped with Er 3+ and Yb 3+ 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 light-emitting 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 Y 2 O 2 S compound doped with 2 at % Er 3+ ions and 6 at % Yb 3+ 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 η = 1.2 lm/W at an applied voltage of 1.5 V.