Alkali metal acetates as effective electron injection layers for organic electroluminescent devices

Design of Hole Blocking Layer with Electron Transport Channels for High Performance Polymer Light‐Emitting Diodes

“…[1,2] However, the stability and performance of PLEDs are in needs of further improvement due to imbalanced hole and electron fluxes and poor charge injection efficiency. Therefore, considerable efforts have been devoted to the studies on interfacial engineering for improving the device performance, which include modifications of indium tin oxide (ITO), [3,4] use of alkaline metal fluorides [5,6] and inorganic salt [7][8][9][10][11] as cathode, and incorporation of hole blocking/electron transport layer. [12,13] The various materials, like low work function metals Ca and Ba, [14,15] thin insulator layers LiF and CsF both covered with Al, [5,6] composite cathodes LiF and CsF both covered with Ca, [16] and inorganic salts CH 3 COOCs, NaOH, and Cs 2 CO 3 all covered with Al, [7][8][9][10][11] were all used as an electron injection layer/cathode in an attempt to enhance the electron injection in the OLEDs or PLEDs.…”

Dual role of LiF as a hole-injection buffer in organic light-emitting diodes

“…[2][3][4][5][6][7][8][9][10][11][12][13] It has been found that the introduction of thin layers of insulating buffers, including LiF, NaCl, alkali metal acetates, CsF, poly͑methyl methacrylate͒ ͑PMMA͒, Al 2 O 3 , sodium stearate, 2-8 between electrodes and organic layers, is an effective way to enhance the current injection and lower the operating voltage. In the case of using LiF or CsF as the buffer, dissociation of the alkali halide and subsequent ''doping'' of the alkali into the organic was suggested as a possible mechanism leading to the enhanced electron injection.…”

“…It can be seen that the current characteristics of H-OLEDs are similar to those reported literatures. [2][3][4][5][6][7][8]10,11 That means the hole injection is increased with the thickness of the LiF buffer in the thin range ͑0.1-7.0 nm͒ and decreased gradually in the thick one ͑7.0-11.0 nm͒. Hence, there is an optimal thickness of 7.0 nm for the hole injection, which dramatically enhances the hole injection and reduces the operating voltage.…”

Organic Semiconductor Electroluminescent Materials

“…The typical electron injection materials are alkali metal compounds and alkaline earth metal compound [29][30][31], such as Li 2 O, Cs 2 CO 3 , CH 3 COOM (M=Li, Na, K, Rb, Cs), LiF, CsF, and so on. The most popular electron injection material is LiF [32,33], which is still widely used at the present day.…”