Electronic structures and electron-injection mechanisms of cesium-carbonate-incorporated cathode structures for organic light-emitting devices

Abstract

In this letter, we investigate electronic structures and electron-injection mechanisms of the effective cathode structures for organic light-emitting devices incorporating cesium carbonate ͑Cs 2 CO 3 ͒, either deposited as an individual thin injection layer or doped into the organic electron-transport layers. The electronic structures and the interface chemistry studied by ultraviolet and x-ray photoemission spectroscopy show that the enhanced electron injection is associated with strong n-doping effects and increase of electron concentrations in the electron-transport layer induced by Cs 2 CO 3. Since such a reaction occurs without the presence of metals, cathode structures incorporating Cs 2 CO 3 may be applied to a wide range of electrode materials.

Rubidium-Carbonate-Doped 4,7-Diphenyl-1,10-phenanthroline Electron Transporting Layer for High-Efficiency p-i-n Organic Light Emitting Diodes

“…Alkali metals such as Li and Cs 5-7 or alkali metal carbonate like Cs 2 CO 3 14,15 have been applied as n-dopants. However, limited work [14][15][16] has been carried out for the application of a metal carbonate-based n-doping system, requiring further research and development on the efficient n-doping system.In this work, we report on the electrical properties and possible charge-transport mechanisms of a newly developed rubidium carbonate ͑Rb 2 CO 3 ͒-doped ETL system by means of a single carrier device test and photoemission spectroscopy analysis. Highefficiency p-i-n OLEDs are also fabricated using the developed n-doping system.…”

“…Alkali metals such as Li and Cs [5][6][7] or alkali metal carbonate like Cs 2 CO 3 14,15 have been applied as n-dopants. However, limited work [14][15][16] has been carried out for the application of a metal carbonate-based n-doping system, requiring further research and development on the efficient n-doping system.…”

Reduction of the dark current in a P3HT-based organic photodiode with a ytterbium-fluoride buffer layer for electron transport

“…The device without the ETL showed that contact between P3HT: PC 60 BM and Al is not suitable since the deposition of Al damages the organic surface [20]. With respect to ETL properties, YbF 3 is suitable for covering the P3HT:PC 60 BM due to its larger optimum thickness compared to LiF and other ETL materials [21,22]. With respect to illuminated conditions, the device with YbF 3 performed the best, recording an E.Q.E of 53.73%, while the device with LiF recorded an E.Q.E of 48.81% at 520nm, as shown in Fig.…”

Modifications of ZnO Interlayer to Improve the Power Conversion Efficiency of Organic Photovoltaic Cells

“…Additionally, various n type electron extraction layers have been developed, such as zinc oxide [30,31], lithium fluoride [32], titanium dioxide [27] and cesium carbonate [33,34].…”