| abstract |
An opto-electrical device comprising: an anode electrode (10); a cathode electrode (11); and an opto-electrically active region (12) located between the electrodes; the cathode electrode including a first layer (15) comprising a compound of a group 1, group 2 or transition metal; a second layer (16) comprising a material having a work function below 3.5 eV; and a third layer (17) spaced from the opto-electrically active region by the first and second layers and having a work function above 3.5 eV. |