Improvement of device efficiency for blue organic light emitting diodes by controlling the Cs2CO3-doped electron transport layer

This is the authors' abstract. We don't add key points for this paper.

The electronic transport properties of 1, 3, 5-tri(1-phenyl-1H-benzo[d]imidazol-2-yl)phenyl (TPBI) electron transporting layers (ETLs) have been investigated as a function of cesium carbonate (Cs2CO3) doping for organic light-emitting diodes (OLEDs). The current density-voltage and light emission characteristics were measured as a function of the Cs2CO3-doped ETL thickness. Cs2CO3-doped TPBI decreased OLED operating voltage by 26% and increased device luminance by 17% in a wide concentration range (3.5% to 10.5%) compared to undoped devices. The effects of 7% Cs2CO3-doped ETL thickness indicated that the operating voltage continuously decreased to 37% when the ETL thickness increased to 600 Å and luminance output continued to increase to 21% at ETL thickness 525 Å. The blue OLED can be optimized by adjusting the thicknesses of Cs2CO3-doped TPBI ETL to balance the electron and hole injection.