Low Driving Voltage and High Efficiency Blue Phosphorescent OLED
| Autor: | Yu-Hao Liu, 劉育豪 |
|---|---|
| Rok vydání: | 2012 |
| Druh dokumentu: | 學位論文 ; thesis |
| Popis: | 100 In this thesis, we use various oxadiazole small molecular, there is 2-phenyl-5-(4-(triphenylsilyl)phenyl)-1,3,4-oxadiazole(SiOXD-1)、diphenylbis(4-(5-phenyl-1,3,4-oxadiazol-2-yl)phenyl)silane(SiOXD-2) and 2,5-bis(4-(triphenylsilyl)phenyl)-1,3,4-oxadiazole(DiSiOXD). Because its wide energy gap can be use as emitting layer(EML) in our organic light-emitting diodes(OLED). For optimizing the low driving voltage and high efficiency OLED that we compared the three kind OXD materials with dopant FIrpic as EML in various concentration. And change three kind of electron transport materials to reduce the driving voltage. The ETL are 3-(4-Biphenylyl) -4- phenyl- 5-tert-butylphenyl-1,2.4-triazole,TAZ)、 2,5-bis(4-(triphenylsilyl)phenyl)-1,3,4-oxadiazole(DiSiOXD) 、4,7-diphenyl-1,10-phenanthroline(BPhen). In this project, we obtained a high efficiency 42.3 cd/A、32.9 lm/W and EQE 14.1%. The device structure is NPB(50 nm)/mCP(10 nm)/15%FIirpic:DiSiOXD(30 nm)/DiSiOXD(20 nm)/TAZ(20 nm). In order to reduce the driving voltage, we use the Tungsten Oxide(WO3) as the hole injection layer (HIL). Observed the electrical change in the different WO3 thinkness. In this way, we obtained an excellent efficiency and low driving voltage 26.3 cd/A、20.7 lm/W and EQE 7.66%. The device structure is WO3 (1 nm)/mCP(60 nm)/15%FIirpic:DiSiOXD(30 nm)/DiSiOXD(35 nm)/BPhen(5 nm). In order to increase the efficiency, we use the double emitting-layer as EML.The host is mCP another host is DiSiOXD, both dopant by FIrpic .In this case, we obtained a high efficiency and low driving voltage 35.3 cd/A、27.7 lm/W and EQE 9.95%. The device structure is WO3(1 nm)/mCP(40nm)/9%FIrpic:mCP(20nm)/15%FIrpic:DiSiOXD(30nm)/ DiSiOXD(35 nm)/BPhen(5 nm). |
| Databáze: | Networked Digital Library of Theses & Dissertations |
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