Efficient Organic Light Emitting Diodes Using Solution-Processed Alkali Metal Carbonate Doped ZnO as Electron Injection Layer

Abstract

In this study, we demonstrate highly efficient, inverted organic light-emitting diodes (IOLEDs) using solution-processed alkali metal carbonate doped ZnO as an electron injection layer (EIL) and tris-(8-hydroxyquinoline) aluminum (Alq 3 ) as an emitter layer. In order to enhance the electron injection efficiency of the IOLEDs, the ZnO EIL layers were modified by doping various alkali metal carbonate materials, including Li 2 CO 3 , Na 2 CO 3 , K 2 CO 3 , and Cs 2 CO 3 , using the low-temperature wet-chemical method. Compared to the control neat ZnO EIL-based IOLEDs, the alkali metal carbonate doped ZnO EIL-based IOLEDs possess obviously improved device performance. An optimal current efficiency of 6.04 cd A −1 were realized from the K 2 CO 3 doped ZnO EIL based IOLED, which is 54% improved compared to that of the neat ZnO EIL based device. The enhancement is ascribed to the increased electron mobility and reduced barrier height for more efficient electron injection. Our results indicate that alkali metal carbonate doped ZnO has promising potential for application in highly efficient solution-processed OLEDs.

Adsorptive potential of ZnO/SiO2 nanorods prepared via the sol–gel method for the removal of Pb(II) and Cd(II) from petroleum refinery wastewater

“…This is within the standard value of 23.0 eV for Zn 2+ 62 . A similar value (23.00 eV) has been reported previously 63 for ZnO nanoparticles, though obtained with different synthetic methods. This result confirms that the Zn exists mostly as Zn 2+ surrounded by the O 2− oxidation state in the hexagonal wurtzite ZnO form.…”

Inverted device architecture for high efficiency single-layer organic light-emitting diodes with imbalanced charge transport

“…For a single-layer OLED, efficient charge injection via ohmic contacts is a crucial prerequisite, since blocking layers are absent 9 . For an inverted OLED, a low work function transparent bottom electrode is thus required 15 . Several attractive options for such bottom electrodes have been published, among which is a ZnO electrode with a thin polyethyleneimine layer to reduce the work function down to 3.1 eV 16 .…”

Effect of Carbonate Source on the Dehydrofluorination Process in Polyvinylidene Fluoride/Alkali Metal Carbonate Composites

“…In addition, the variation of the carbonate source may exert a significant influence on the dehydrofluorination reactions and thus the final properties of activated carbon, because of the distinct properties of the carbonates caused by the difference in the cations. For instance, it has been reported that ZnO films doped with various alkaline metal carbonates showed quite different electron mobilities and work functions, which could lead to different electron injection properties of these devices and differences in the device performance. , Moreover, the incorporation of ion-rich materials in the composite can provide faster ion transport when the composite is charged . In particular, smaller ions can easily disperse to be adsorbed in the nanopores of AC and contribute to increasing the charging and discharging rates of the electrode.…”