White organic light-emitting diodes(WOLEDs)have several desirable features,but their commercialization is hindered by the poor stability of blue light emitters and high production costs due to complicated device struc...White organic light-emitting diodes(WOLEDs)have several desirable features,but their commercialization is hindered by the poor stability of blue light emitters and high production costs due to complicated device structures.Herein,we investigate a standard blue emitting hole transporting material(HTM)N,N'-bis(naphthalen-1-yl)-N,N'-bis(phenyl)benzidine(NPB)and its exciplex emission upon combining with a suitable electron transporting material(ETM),3-(biphenyl-4-yl)-5-(4-tert-butylphenyl)-4-phenyl-4H-1,2,4-triazole(TAZ).Blue and yellow OLEDs with simple device structures are developed by using a blend layer,NPB:TAZ,as a blue emitter as well as a host for yellow phosphorescent dopant iridium(III)bis(4-phenylthieno[3,2-c]pyridinato-N,C2')acetylacetonate(PO-01).Strategic device design then exploits the ambipolar charge transport properties of tetracene as a spacer layer to connect these blue and yellow emitting units.The tetracene-linked device demonstrates more promising results compared to those using a conventional charge generation layer(CGL).Judicious choice of the spacer prevents exciton difusion from the blue emitter unit,yet facilitates charge carrier transport to the yellow emitter unit to enable additional exciplex formation.This complementary behavior of the spacer improves the blue emission properties concomitantly yielding reasonable yellow emission.The overall white light emission properties are enhanced,achieving CIE coordinates(0.36,0.39)and color temperature(4643 K)similar to daylight.Employing intermolecular exciplex emission in OLEDs simplifes the device architecture via its dual functionality as a host and as an emitter.展开更多
基金support by DST-SERB,Govt.of India(CRG/2020/003699)CKV and KNNU acknowledge support from DST-AISRF program of the Department of Science and Technology,Government of India(DST/INT/AUS/P-74/2017)support from Council of Scientifc and Industrial Research(CSIR),Government of India for the award of a research fellowship.AKS acknowledges support from DST-INSPIRE for the award of a research fellowship.
文摘White organic light-emitting diodes(WOLEDs)have several desirable features,but their commercialization is hindered by the poor stability of blue light emitters and high production costs due to complicated device structures.Herein,we investigate a standard blue emitting hole transporting material(HTM)N,N'-bis(naphthalen-1-yl)-N,N'-bis(phenyl)benzidine(NPB)and its exciplex emission upon combining with a suitable electron transporting material(ETM),3-(biphenyl-4-yl)-5-(4-tert-butylphenyl)-4-phenyl-4H-1,2,4-triazole(TAZ).Blue and yellow OLEDs with simple device structures are developed by using a blend layer,NPB:TAZ,as a blue emitter as well as a host for yellow phosphorescent dopant iridium(III)bis(4-phenylthieno[3,2-c]pyridinato-N,C2')acetylacetonate(PO-01).Strategic device design then exploits the ambipolar charge transport properties of tetracene as a spacer layer to connect these blue and yellow emitting units.The tetracene-linked device demonstrates more promising results compared to those using a conventional charge generation layer(CGL).Judicious choice of the spacer prevents exciton difusion from the blue emitter unit,yet facilitates charge carrier transport to the yellow emitter unit to enable additional exciplex formation.This complementary behavior of the spacer improves the blue emission properties concomitantly yielding reasonable yellow emission.The overall white light emission properties are enhanced,achieving CIE coordinates(0.36,0.39)and color temperature(4643 K)similar to daylight.Employing intermolecular exciplex emission in OLEDs simplifes the device architecture via its dual functionality as a host and as an emitter.
