Organic/inorganic heterostructures for enhanced electroluminescence

In this work, organic/inorganic heterostructure electroluminescence devices are fabricated, in which the inorganic layers (ZnO, ZnS) act as the electron transfer layer and the hole blocking layer. Compared to single-organic-layer (MEH-PPV) devices, the heterostructure devices have a significantly enhanced luminous efficiency. The influences of the electric field and the barrier potential on the improvements in performance are analyzed in detail. The results are: (i) the introduction of the inorganic layer makes the injection of electrons easier; (ii) the hole current density is enhanced by the increase of the electric field in the organic layer due to a high dielectric constant of the inorganic layer and accumulation of electrons at the inorganic/organic interface; (iii) the electron-hole current density balance is improved. (c) 2007 Elsevier Ltd. All rights reserved.