Improved electron injection in organic light-emitting devices with a lithium acetylacetonate [Li(acac)]/aluminium bilayer cathode
Data(s) |
2007
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Resumo |
Lithium acetylacetonate [Li(acac)] covered with aluminium was used as an efficient electron injection layer in organic light-emitting devices (OLEDs) consisting of NPB as the hole transport layer and Alq(3) as the electron transport and light emitting layer, resulting in lower turn- on voltage and increased current efficiency. The turn- on voltage (the voltage at a luminance of 1 cd m(-2)) was decreased from 5.5 V for the LiF/Al and 4.4 V for Ca/Al to 4.0 V for Li(acac)/Al, and the device current efficiency was enhanced from 4.71 and 5.2 to 7.0 cd A(-1). The performance tolerance to the layer thickness of Li(acac) is also better than that of the device with LiF. LiF can only be used when deposited as an ultra- thin layer because of its highly insulating nature, while the Li(acac) can be as thick as 5 nm without significantly affecting the EL performance. We suppose that the free lithium released from Li(acac) improves the electron injection when Li(acac) is covered with an Al cathode. |
Identificador | |
Idioma(s) |
英语 |
Fonte |
Shi SW;Ma DG;Peng JB.Improved electron injection in organic light-emitting devices with a lithium acetylacetonate [Li(acac)]/aluminium bilayer cathode,SEMICONDUCTOR SCIENCE AND TECHNOLOGY,2007 ,22(3):249-252 |
Palavras-Chave | #ELECTROLUMINESCENT DEVICES #AL/LIF ELECTRODE #BUFFER-LAYER #DIODES #ENHANCEMENT #MECHANISMS #ALUMINUM |
Tipo |
期刊论文 |