Organic Light-Emitting Diodes by Doping Liq into an Electron Transport Layer
具有新型电子传输层的有机薄膜电致发光器件

Organic light emitting diodes (OLEDs) incorporating an n-doping transport layer comprised of 8-hydroxy-quinolinato lithium (Liq) doped into 4'7- diphyenyl-1,10-phenanthroline (BPhen) as ETL and a p-doping transport layer that includes tetrafluro-tetracyano-quinodimethane (F4- TCNQ) doped into 4,4',4"-tris (3-methylphenylphenylamono) triphenylamine (m-MTDATA) are demonstrated. In order to examine the improvement in the conductivity of transport layers,hole-only and electron-only devices are fabricated. The current and power efficiency of organic light-emitting diodes are improved significantly after introducing an n-doping (BPhen33wt% Liq) layer as an electron transport layer (ETL) and a p-doping layer composed of m-MTDATA and F4- TCNQ as a hole transport layer (HTL). Compared with the control device (without doping) ,the current efficiency and power efficiency of the most efficient device (device C) are enhanced by approximately 51% and 89%, respectively, while driving voltage is reduced by 29%. This improvement is attributed to the improved conductivity of the transport layers that leads to efficient charge balance in the emission zone.