Two-layer light emitting diodes prepared by the sol-gel route

We have elaborated organic-inorganic hybrid light-emitting diodes (HLED). These devices emitting in the green are formed of two hybrid thin layers, exhibiting different functionalities, which are sandwiched between indium-tin oxide (ITO) and metallic electrodes. These layers have been prepared from silane precursors modified with hole transporting units and light-emitting naphthalimide moieties by the sol-gel technique. The hole transporting sol-gel layers exhibit about the same charge mobility as organic polymers having equivalent active units. The maximum external quantum efficiency of the best diode using LiF/Al cathode is about 1% and the luminance reaches 4000 cd.m(-2). (C) 2000 Academie des sciences/Editions scientifiques et medicales Elsevier SAS.