The color-tunable white organic light-emitting diode (CT-WOLED) with wide correlation color temperature (CCT) has many advantages in optimizing the artificial light source to adapt to the human physiological cycle. Th...The color-tunable white organic light-emitting diode (CT-WOLED) with wide correlation color temperature (CCT) has many advantages in optimizing the artificial light source to adapt to the human physiological cycle. The research on the change trend of CCT and the law of extending the change range of CCT will help to further improve the performance of this kind of device. The present work fabricated a series of CT-WOLED devices with a simple structure, which are all composed of two ultra-thin phosphor layers (PO-01 and Flrpic) and a spacer interlayer. The yellow interface exciplex (TCTA/PO-T2T) formed between the spacer layer (PO-T2T) and transmission material (TCTA) in EML will decrease the CCT value at low voltage. The relationship between the energy transfer in EML and CCT change trend is investigated by adjusting the interface exciplexes and the thickness of the interlayer or the phosphor layer in devices A, B and C, respectively. The results demonstrate that a simple OLED device with an interlayer inserted between two ultra-thin phosphor layers can achieve a wider CCT span from 3359 K to 6451 K at voltage increases from 2.75 V to 8.25 V. .展开更多
The stable spectrum can be obtained when the voltage changes, which is a necessary condition for the white organic light emitting diode (WOLED) device to be widely used in the field of solid-state lighting. However, w...The stable spectrum can be obtained when the voltage changes, which is a necessary condition for the white organic light emitting diode (WOLED) device to be widely used in the field of solid-state lighting. However, with the increase of voltage, the movement of the recombination zone (RZ) is inevitable because the perfect bipolar host material is difficult to obtain, which will redistribute the energy in the light emitting layer (EML) and affect the stability of the spectrum. We fabricate a series of ternary hybrid WOLEDs with a simple structure by inserting ultra-thin PO-T2T into the blue exciplex (TCTA:TPBi) to form the green interface exciplex. Without considering the movement of RZ, device B2 realizes the dynamic balance energy distribution in EML and stable spectrum by controlling two processes of the Dexter energy transfer and exciton capture. By modifying the doping ratio of the host material, we also find that the broadened RZ is helpful to further improve the spectral stability of the device. When the voltage changes from 3 V to 7 V, the change range of color coordinates is only (0.026, 0.025).展开更多
This paper reports the fabrication of novel white organic light-emitting device（WOLED） by using a high efficiency blue fluorescent dye N-（4-（（E）-2-（6-（（E）-4-（diphenylamino）styryl）naphthalen-2-yl）vinyl）p...This paper reports the fabrication of novel white organic light-emitting device（WOLED） by using a high efficiency blue fluorescent dye N-（4-（（E）-2-（6-（（E）-4-（diphenylamino）styryl）naphthalen-2-yl）vinyl）phenyl）oN- phenylbenzenamine （N-BDAVBi） and a red phosphoresecent dye bis （1-（phenyl） isoquinoline） iridium （III） acetylanetonate （Ir（piq）2（acac））. The configuration of the device was ITO/PVK：TPD/CBP： N-BDAVBi /CBP/ BALq： Ir（piq）2（acac）/BCP/Alq3/LiF：AL. By adjusting the proportion of the dopants （N-BDAVBi, Ir（piq）2（acac）） in the light-emitting layer, white light with Commission Internationale de l＇Eclairage （CIE） coordinates of （0.35, 0.35） and a maximum luminance of 25350cd/m2 were obtained external quantum and current efficiency of 6.78% and between the two light-emitting layers and using BCP at an applied voltage of 22V. The WOLED exhibits maximum 12cd/A respectively. By placing an undoped spacer CBP layer as hole blocking layer, the colour stabilization slightly changed when the driving voltage increased from 6 to 22 V.展开更多
A white organic light emitting device(WOLED) combining the blue organic light emitting device with a red color conversion layer(CCL) is reported,which includes a fluorescent material N-(4-((E)-2-(6-((E)-4-(diphenylami...A white organic light emitting device(WOLED) combining the blue organic light emitting device with a red color conversion layer(CCL) is reported,which includes a fluorescent material N-(4-((E)-2-(6-((E)-4-(diphenylamino) styryl)naphtha len-2-yl)vinyl) phenyl)-N-phenylbenzenamine(N-BDAVBi) doped into 4,4'-N,N'-dicarbazole-biphenyl(CBP) as the blue light emitting layer,and the poly(2-methoxy-5-(2'-ethylhexoxy)-1,4-phenylene vinylene(MEH-PPV) as a red CCL.By optimizing the concentration of MEH-PPV in the CCL,a good white light emission is obtained,which shows that the stable CIE coordinates of(0.33,0.34) will have a slight change when the driving voltage is increased from 6 to 11 V.The maximum brightness and current efficiency of the optimized device are 11294 cd/m2 and 6.4 cd/A,respectively.展开更多
Tandem white organic light-emitting diodes(WOLEDs) are of great research interest since they can greatly boost the performance compared with the single-unit counterparts. However, their structures are more complicated...Tandem white organic light-emitting diodes(WOLEDs) are of great research interest since they can greatly boost the performance compared with the single-unit counterparts. However, their structures are more complicated than those of single-unit OLEDs. Besides, to achieve high performance, the doping technology is required to tandem OLEDs, particularly for tandem WOLEDs, further complicating the structures. Herein, doping-free tandem WOLEDs, for the first time, have been demonstrated. By managing an effective doping-free charge generation layer to interconnect doping-free emitting layers/charge transport layers, high-performance doping-free tandem WOLEDs have been developed. The blueyellow device accomplishes the simplified structure/short fabrication time/reduced cost/high efficiency/low efficiency roll-off/low voltage/high luminance trade-off, which cannot be achieved by previous tandem WOLEDs. Remarkably, the efficiency(81.2 cd A^(-1)) is ~2-fold higher than the highest efficiency of previous doping-free WOLEDs and even higher than those of some best doping tandem WOLEDs. The maximum luminance is 44,886 cd m^(-2), which is the highest for doping-free WOLEDs.Besides, the blue-red device can exhibit a color rendering index(CRI) of 67, which is even higher than that of some representative three-color tandem WOLEDs. Such findings may not only represent a significant step for doping-free WOLEDs, but unlock a novel avenue that doping-free tandem WOLEDs are promising to achieve the simplicity and high performance trade-off.展开更多
High luminous efficiency and high color rendering index(CRI) are both the foremost factors for white organic lightemitting diodes(WOLEDs) to serve as next generation solid-state lighting sources. In this paper, we sho...High luminous efficiency and high color rendering index(CRI) are both the foremost factors for white organic lightemitting diodes(WOLEDs) to serve as next generation solid-state lighting sources. In this paper, we show that both luminous efficiency and CRI can be improved by adjusting the green/red spectra of WOLEDs. With green emission spectra matching with the human photopic curve, the WOLEDs exhibit higher luminous efficiency and higher CRI. Theoretical calculation shows that by tuning the white emission spectra to maximally match with the human photopic curve, the luminous efficiency can be improved by 41.8% without altering the color coordinates, the color correlated temperature(CCT) and the external quantum efficiency(EQE) of the WOLEDs.展开更多
文摘The color-tunable white organic light-emitting diode (CT-WOLED) with wide correlation color temperature (CCT) has many advantages in optimizing the artificial light source to adapt to the human physiological cycle. The research on the change trend of CCT and the law of extending the change range of CCT will help to further improve the performance of this kind of device. The present work fabricated a series of CT-WOLED devices with a simple structure, which are all composed of two ultra-thin phosphor layers (PO-01 and Flrpic) and a spacer interlayer. The yellow interface exciplex (TCTA/PO-T2T) formed between the spacer layer (PO-T2T) and transmission material (TCTA) in EML will decrease the CCT value at low voltage. The relationship between the energy transfer in EML and CCT change trend is investigated by adjusting the interface exciplexes and the thickness of the interlayer or the phosphor layer in devices A, B and C, respectively. The results demonstrate that a simple OLED device with an interlayer inserted between two ultra-thin phosphor layers can achieve a wider CCT span from 3359 K to 6451 K at voltage increases from 2.75 V to 8.25 V. .
文摘The stable spectrum can be obtained when the voltage changes, which is a necessary condition for the white organic light emitting diode (WOLED) device to be widely used in the field of solid-state lighting. However, with the increase of voltage, the movement of the recombination zone (RZ) is inevitable because the perfect bipolar host material is difficult to obtain, which will redistribute the energy in the light emitting layer (EML) and affect the stability of the spectrum. We fabricate a series of ternary hybrid WOLEDs with a simple structure by inserting ultra-thin PO-T2T into the blue exciplex (TCTA:TPBi) to form the green interface exciplex. Without considering the movement of RZ, device B2 realizes the dynamic balance energy distribution in EML and stable spectrum by controlling two processes of the Dexter energy transfer and exciton capture. By modifying the doping ratio of the host material, we also find that the broadened RZ is helpful to further improve the spectral stability of the device. When the voltage changes from 3 V to 7 V, the change range of color coordinates is only (0.026, 0.025).
文摘This paper reports the fabrication of novel white organic light-emitting device（WOLED） by using a high efficiency blue fluorescent dye N-（4-（（E）-2-（6-（（E）-4-（diphenylamino）styryl）naphthalen-2-yl）vinyl）phenyl）oN- phenylbenzenamine （N-BDAVBi） and a red phosphoresecent dye bis （1-（phenyl） isoquinoline） iridium （III） acetylanetonate （Ir（piq）2（acac））. The configuration of the device was ITO/PVK：TPD/CBP： N-BDAVBi /CBP/ BALq： Ir（piq）2（acac）/BCP/Alq3/LiF：AL. By adjusting the proportion of the dopants （N-BDAVBi, Ir（piq）2（acac）） in the light-emitting layer, white light with Commission Internationale de l＇Eclairage （CIE） coordinates of （0.35, 0.35） and a maximum luminance of 25350cd/m2 were obtained external quantum and current efficiency of 6.78% and between the two light-emitting layers and using BCP at an applied voltage of 22V. The WOLED exhibits maximum 12cd/A respectively. By placing an undoped spacer CBP layer as hole blocking layer, the colour stabilization slightly changed when the driving voltage increased from 6 to 22 V.
基金supported by the National Natural Science Foundation of China (No. 60906022)the Scientific Developing Foundation of Tianjin Education Commission (No. 20070805)
文摘A white organic light emitting device(WOLED) combining the blue organic light emitting device with a red color conversion layer(CCL) is reported,which includes a fluorescent material N-(4-((E)-2-(6-((E)-4-(diphenylamino) styryl)naphtha len-2-yl)vinyl) phenyl)-N-phenylbenzenamine(N-BDAVBi) doped into 4,4'-N,N'-dicarbazole-biphenyl(CBP) as the blue light emitting layer,and the poly(2-methoxy-5-(2'-ethylhexoxy)-1,4-phenylene vinylene(MEH-PPV) as a red CCL.By optimizing the concentration of MEH-PPV in the CCL,a good white light emission is obtained,which shows that the stable CIE coordinates of(0.33,0.34) will have a slight change when the driving voltage is increased from 6 to 11 V.The maximum brightness and current efficiency of the optimized device are 11294 cd/m2 and 6.4 cd/A,respectively.
基金supported by the National Basic Research Program of China(2015CB655004)the National Natural Science Foundation of China(61401156,U1601651,and U1301243)+3 种基金Pearl Rive S&T Nova Program of Guangzhou(201710010066,201610010052)the Fundamental Research Funds for the Central Universities(2017MS008)China Postdoctoral Science Foundation(2017T100627)Tiptop Scientific and Technical Innovative Youth Talents of Guangdong Special Support Program(2015TQ01C777,2016TQ03C331)
文摘Tandem white organic light-emitting diodes(WOLEDs) are of great research interest since they can greatly boost the performance compared with the single-unit counterparts. However, their structures are more complicated than those of single-unit OLEDs. Besides, to achieve high performance, the doping technology is required to tandem OLEDs, particularly for tandem WOLEDs, further complicating the structures. Herein, doping-free tandem WOLEDs, for the first time, have been demonstrated. By managing an effective doping-free charge generation layer to interconnect doping-free emitting layers/charge transport layers, high-performance doping-free tandem WOLEDs have been developed. The blueyellow device accomplishes the simplified structure/short fabrication time/reduced cost/high efficiency/low efficiency roll-off/low voltage/high luminance trade-off, which cannot be achieved by previous tandem WOLEDs. Remarkably, the efficiency(81.2 cd A^(-1)) is ~2-fold higher than the highest efficiency of previous doping-free WOLEDs and even higher than those of some best doping tandem WOLEDs. The maximum luminance is 44,886 cd m^(-2), which is the highest for doping-free WOLEDs.Besides, the blue-red device can exhibit a color rendering index(CRI) of 67, which is even higher than that of some representative three-color tandem WOLEDs. Such findings may not only represent a significant step for doping-free WOLEDs, but unlock a novel avenue that doping-free tandem WOLEDs are promising to achieve the simplicity and high performance trade-off.
基金supported by the National Natural Science Foundation of China(No.61405089)the Innovation of Science and Technology Committee of Shenzhen(No.JCYJ20140417105742713)
文摘High luminous efficiency and high color rendering index(CRI) are both the foremost factors for white organic lightemitting diodes(WOLEDs) to serve as next generation solid-state lighting sources. In this paper, we show that both luminous efficiency and CRI can be improved by adjusting the green/red spectra of WOLEDs. With green emission spectra matching with the human photopic curve, the WOLEDs exhibit higher luminous efficiency and higher CRI. Theoretical calculation shows that by tuning the white emission spectra to maximally match with the human photopic curve, the luminous efficiency can be improved by 41.8% without altering the color coordinates, the color correlated temperature(CCT) and the external quantum efficiency(EQE) of the WOLEDs.
