摘要
Novel and simplified bi-layer top-emitting white organic light emitting diodes(OLEDs)with dual co-host emitters have been simulated and analyzed.They consist of yellow-green emitting layer(EML)as electron transport layer(ETL)and blue EML as hole transport layer(HTL).Novelty of the device lies in simplification of tri-layer white OLED to a bi-layered device which is done by merging yellow-green EML with ETL and blue EML with HTL.The simulated devices show Commission Internationale de L’Eclairage(CIE)colour coordinates well within the emission range of white light.The results show that device A with 5,6,11,12-tetraphenylnaphthacene(rubrene)doped ETL has achieved the lowest luminance but longest excited state lifetime.Device D with tris-(8-hydroxyquinoline)aluminum:4-(dicyanomethylene)-2-t-butyle-6-(1,1,7,7-tetra-methyljulolidyl-9-enyl)4 H-pyran(Alq3:DCJTB)as ETL which emits yellow light and 2,7-bis[N,N-bis(4-methoxy-phenyl)amino]-9,9-spirobifluorene(MS-TPD):bis(2-methyl-8-quninolinato)-4-phenylphenolate alu-minium(BAlq)as HTL which is responsible for blue light emission is found to have best characteristics when compared to other simulated devices.It has a maximum luminance of 10000 cd/m2 and current efficiency of 15.25 cd/A,respectively,and CIE coordinates are at(0.329,0.319).The device is found to be compatible to be used in solid state lighting applications because of the low driving voltage of the device.
