Electronic device comprising at least one light emitting layer between an anode (10, 20) and a silver cathode (13, 25), the device further comprising between the cathode (13, 25) and the anode (10, 20) at least one mixed layer comprising (i) at least one covalent electron transport matrix compound which is a compound comprising elements bound together mostly by covalent bonds comprising at least one polar group selected from phosphine oxide group or diazole group, (ii) in elemental form, an electropositive element selected from substantially non-radioactive alkali metals, alkaline earth metals, rare earth metals, and transition metals of the fourth period of the Periodic table having proton numbers 22,23,24,25,26,27,28,29; characterized in that the reduction potential of the electron transport matrix compound, if measured by cyclic voltammetry under the same conditions, has the value which is more negative than the value obtained for tris(2-benzo[d]thiazol-2-yl)phenoxyaluminum, preferably more negative than for 9,9',10,10'-tetraphenyl-2,2'-bianthracene or 2,9-di([1,1'-biphenyl]-4-yl)-4,7-diphenyl-1,10-phenanthroline, more preferably more negative than for 2,4,7,9-tetraphenyl-1,10-phenanthroline, even more preferably more negative than for 9,10-di(naphthalen-2-yl)-2-phenylanthracene, even more preferably more negative than for 2,9-bis(2-methoxyphenyl)-4,7-diphenyl-1,10-phenanthroline, even more preferably more negative than for 9,9'-spirobi[fluorene]-2,7-diylbis(diphenylphosphine oxide), even more preferably more negative than for 4,7-diphenyl-1,10-phenanthroline, even more preferably more negative than for 1,3,5-tris(1-phenyl-1H-benzimidazol-2-yl)benzene, most preferably more negative than for pyrene and still preferably more negative than the value obtained for [1,1'-binaphthalen]-2,2'-diylbis(diphenylphosphine oxide). (i) at least one covalent electron transport matrix compound which is a compound comprising elements bound together mostly by covalent bonds comprising at least one polar group selected from phosphine oxide group or diazole group, (ii) in elemental form, an electropositive element selected from substantially non-radioactive alkali metals, alkaline earth metals, rare earth metals, and transition metals of the fourth period of the Periodic table having proton numbers 22,23,24,25,26,27,28,29; characterized in that the reduction potential of the electron transport matrix compound, if measured by cyclic voltammetry under the same conditions, has the value which is more negative than the value obtained for tris(2-benzo[d]thiazol-2-yl)phenoxyaluminum, preferably more negative than for 9,9',10,10'-tetraphenyl-2,2'-bianthracene or 2,9-di([1,1'-biphenyl]-4-yl)-4,7-diphenyl-1,10-phenanthroline, more preferably more negative than for 2,4,7,9-tetraphenyl-1,10-phenanthroline, even more preferably more negative than for 9,10-di(naphthalen-2-yl)-2-phenylanthracene, even more preferably more negative than for 2,9-bis(2-methoxyphenyl)-4,7-diphenyl-1,10-phenanthroline, even more preferably more negative than for 9,9'-spirobi[fluorene]-2,7-diylbis(diphenylphosphine oxide), even more preferably more negative than for 4,7-diphenyl-1,10-phenanthroline, even more preferably more negative than for 1,3,5-tris(1-phenyl-1H-benzimidazol-2-yl)benzene, most preferably more negative than for pyrene and still preferably more negative than the value obtained for [1,1'-binaphthalen]-2,2'-diylbis(diphenylphosphine oxide).