Fluorescence/phosphorescence hybrid white organic light-emitting devices（WOLEDs） based on double emitting layers（EMLs） with high color stability are fabricated.The simplified EMLs consist of a non-doped blue therm...Fluorescence/phosphorescence hybrid white organic light-emitting devices（WOLEDs） based on double emitting layers（EMLs） with high color stability are fabricated.The simplified EMLs consist of a non-doped blue thermally activated delayed fluorescence（TADF） layer using 9,9-dimethyl-9,10-dihydroacridine-diphenylsulfone（DMAC-DPS） and an ultrathin non-doped yellow phosphorescence layer employing bis[2-（4-tertbutylphenyl）benzothiazolato-N,C2＇]iridium（acetylacetonate）（（tbt）_2Ir（acac））.Two kinds of materials of 4,7-diphenyl-1,10-phenanthroline（Bphen） and 1,3,5-tris（2-Nphenylbenzimidazolyl） benzene（TPBi） are selected as the electron transporting layer（ETL）,and the thickness of yellow EML is adjusted to optimize device performance.The device based on a 0.3-nm-thick yellow EML and Bphen exhibits high color stability with a slight Commission International de l＇Eclairage（CIE） coordinates variation of（0.017,0.009） at a luminance ranging from 52 cd/m^2 to 6998 cd/m^2.The TPBi-based device yields a high efficiency with a maximum external quantum efficiency（EQE）,current efficiency,and power efficiency of 10%,21.1 cd/A,and 21.3 lm/W,respectively.The ultrathin yellow EML suppresses hole trapping and short-radius Dexter energy transfer,so that Forster energy transfer（FRET）from DMAC-DPS to（tbt）_2Ir（acac） is dominant,which is beneficial to keep the color stable.The employment of TPBi with higher triplet excited state effectively alleviates the triplet exciton quenching by ETL to improve device efficiency.展开更多
In this paper,a white organic light-emitting device(WOLEDs) with multiple-emissive-layer structure has been fabricated.The device has a simple structure of indium tin oxide(ITO)/NPB(20 nm)//DPVBi(20 nm)/CDBP:x Ir(btp)...In this paper,a white organic light-emitting device(WOLEDs) with multiple-emissive-layer structure has been fabricated.The device has a simple structure of indium tin oxide(ITO)/NPB(20 nm)//DPVBi(20 nm)/CDBP:x Ir(btp)2acac(10 nm)/Alq3(25 nm)/BCP(5 nm)/Cs F(1 nm)/Al(150 nm)(x= 0.15,2.5 and 3.0 wt%),where NPB and BCP are used as the hole-injecting layer,electron transporting and hole blocking layer,respectively.White light emission was realized in an OLED with 2.5% Ir(btp)2acac doping concentration.The device exhibits peak efficiency of 1.93 cd/A at 9 V and maximum brightness of 7005 cd/m^2 at 14 V.The Commission International de I'Eclairage(CIE)(1931) coordinates of white emission are well within the white zone,which moves from(0.35,0.33) to(0.26,0.30) when the applied voltage is varied from 5 V to 14 V.展开更多
Several highly efficient iridium-complex polymer light-emitting devices （PLEDs） are fabricated, with a newly synthesized blue conjugated polymer, poly[（9,9-bis（4-（2-ethylhexyloxy）phenyl）-fluorene）-co-（3,7-dib...Several highly efficient iridium-complex polymer light-emitting devices （PLEDs） are fabricated, with a newly synthesized blue conjugated polymer, poly[（9,9-bis（4-（2-ethylhexyloxy）phenyl）-fluorene）-co-（3,7-dibenziothiene-S,S- dioxide15）] （PPF-3,TSO15）, chosen as host. High luminous efficiencies of 7.4 cd.A-1 and 27.4 cd.A-1 are achieved in red and green PLEDs, respectively, by optimizing the doping concentrations of red phosphorescent dye iridium bis（1- phenylisoquinoline） （acetylacetonate） （Ir（piq）） and green phosphorescent dye iridium tris（2-（4-tolyl）pyridinato-N, C2＇） （Ir（mppy）3）.Furthermore, highly efficient white PLEDs （WPLEDs） with the Commission Internationale de l＇Eclairage （CIE） coordinates of （0.35, 0.38） are successfully produced by carefully controlling the doping concentration of the irid- ium complex. The obtained WPLEDs show maximal efficiencies of 14.4 cd.A-1 and 10.1 lm.W-1, which are comparable to those of incandescent bulbs. Moreover, the electroluminescent spectrum of the white device with an initial luminance of about 1000 cd.m-2 is stable, subject to constant applied current stress, indicating that good device stability can be obtained in this system.展开更多
A systematic study has been conducted on microcavity organic light emitting diodes(OLEDs)based on green,red and blue phosphorescent emitters to elucidate the microcavity effects for different color emitters.We found t...A systematic study has been conducted on microcavity organic light emitting diodes(OLEDs)based on green,red and blue phosphorescent emitters to elucidate the microcavity effects for different color emitters.We found that the luminance output is determined by the reflectivity of the semitransparent electrode and the photopic response of the green,red and blue emitters.While the luminance enhancements of blue and red phosphorescent microcavity devices are small,a current efficiency as high as 224 cd A21 is obtained in the green phosphorescent microcavity OLEDs.展开更多
Electroluminescence （EL） characteristics have been studied for a hybrid tandem white organic light emitting diode （OLED） with a blue emitting fluorescent EL1 unit based on BCzVBi and a yellow emitting phosphoresce...Electroluminescence （EL） characteristics have been studied for a hybrid tandem white organic light emitting diode （OLED） with a blue emitting fluorescent EL1 unit based on BCzVBi and a yellow emitting phosphorescent EL2 unit based on （fbi）2Ir（acac）, where a MoO3 layer is inserted between EL1 and EL2 units as charge generation layer （CGL）. Maximum current and power efficiencies of 68.1 cd/A and 29.2 lm/W were obtained, respectively, while the current and power efficiencies at luminance of 1000 cd/m2 were 68.0 cd/A and 24.6 lm/W. The yellow emission appears from about 4.5 V firstly, while the blue emission starts to appear from about 5.4 V. It was found that charge generation from CGL of MoO3/NPB bilayer occurred at high voltages of above 5.4 V but not at low voltages below 5.2 V.展开更多
采用真空热蒸镀方法以4,4′-bis(carbazol-9-yl)biphenyl(CBP)为主体材料、以bis[2-(4-tert-butylphenyl)benzothiazolato-N,C2′]iridium(acetylacetonate)[(t-bt)2Ir(acac)]磷光染料为掺杂剂构成黄色发光层,制备了高效白光的有机电致...采用真空热蒸镀方法以4,4′-bis(carbazol-9-yl)biphenyl(CBP)为主体材料、以bis[2-(4-tert-butylphenyl)benzothiazolato-N,C2′]iridium(acetylacetonate)[(t-bt)2Ir(acac)]磷光染料为掺杂剂构成黄色发光层,制备了高效白光的有机电致发光器件(OLEDs).OLEDs的器件结构为indium tin oxide(ITO)/N,N′-bis-(1-naphthyl)-N,N′-biphenyl-1,1′-biphenyl-4,4′-diamine(NPB)/CBP:(t-bt)2Ir(acac)/NPB/2,9-dimethyl-4,7-diphenyl-1,10-phenanthroline(BCP)/8-hydroxyquinoline aluminum(Alq3)/Mg∶Ag,从ITO阳极开始的第一层NPB为空穴传输层,第二层超薄的NPB为蓝色发光层,BCP为空穴阻挡层和激子阻挡层,Alq3为电子传输层.结果表明,器件电压在3V启亮,在16.5V时,器件的最高亮度达到15460cd·m-2;在4V时,器件达到最大流明效率为7.5lm·W-1,器件启亮后所发出的白光光谱在低电压时随电压变化有稍微的移动,但是都在白光范围内变化.在电压达到8V后Commission Internationale de l′Eclairage(国际照明委员会)(CIE)色坐标为(0.33,0.32),并且光谱及色坐标稳定,不随电压变化而改变,与最佳的白光坐标(0.33,0.33)几乎重合.同时,从机理上解释了光谱移动和效率衰减的原因,并探讨了载流子陷阱和能量传递的关系.展开更多
基金Project supported by the National Natural Science Foundation of China(Grant Nos.61675041 and 61605253)the Foundation for Innovation Research Groups of the National Natural Science Foundation of China(Grant No.61421002)the Science&Technology Department Program of Sichuan Province,China(Grant No.2016HH0027)
文摘Fluorescence/phosphorescence hybrid white organic light-emitting devices（WOLEDs） based on double emitting layers（EMLs） with high color stability are fabricated.The simplified EMLs consist of a non-doped blue thermally activated delayed fluorescence（TADF） layer using 9,9-dimethyl-9,10-dihydroacridine-diphenylsulfone（DMAC-DPS） and an ultrathin non-doped yellow phosphorescence layer employing bis[2-（4-tertbutylphenyl）benzothiazolato-N,C2＇]iridium（acetylacetonate）（（tbt）_2Ir（acac））.Two kinds of materials of 4,7-diphenyl-1,10-phenanthroline（Bphen） and 1,3,5-tris（2-Nphenylbenzimidazolyl） benzene（TPBi） are selected as the electron transporting layer（ETL）,and the thickness of yellow EML is adjusted to optimize device performance.The device based on a 0.3-nm-thick yellow EML and Bphen exhibits high color stability with a slight Commission International de l＇Eclairage（CIE） coordinates variation of（0.017,0.009） at a luminance ranging from 52 cd/m^2 to 6998 cd/m^2.The TPBi-based device yields a high efficiency with a maximum external quantum efficiency（EQE）,current efficiency,and power efficiency of 10%,21.1 cd/A,and 21.3 lm/W,respectively.The ultrathin yellow EML suppresses hole trapping and short-radius Dexter energy transfer,so that Forster energy transfer（FRET）from DMAC-DPS to（tbt）_2Ir（acac） is dominant,which is beneficial to keep the color stable.The employment of TPBi with higher triplet excited state effectively alleviates the triplet exciton quenching by ETL to improve device efficiency.
文摘In this paper,a white organic light-emitting device(WOLEDs) with multiple-emissive-layer structure has been fabricated.The device has a simple structure of indium tin oxide(ITO)/NPB(20 nm)//DPVBi(20 nm)/CDBP:x Ir(btp)2acac(10 nm)/Alq3(25 nm)/BCP(5 nm)/Cs F(1 nm)/Al(150 nm)(x= 0.15,2.5 and 3.0 wt%),where NPB and BCP are used as the hole-injecting layer,electron transporting and hole blocking layer,respectively.White light emission was realized in an OLED with 2.5% Ir(btp)2acac doping concentration.The device exhibits peak efficiency of 1.93 cd/A at 9 V and maximum brightness of 7005 cd/m^2 at 14 V.The Commission International de I'Eclairage(CIE)(1931) coordinates of white emission are well within the white zone,which moves from(0.35,0.33) to(0.26,0.30) when the applied voltage is varied from 5 V to 14 V.
基金Project supported by the National Basic Research Program of China (Grant No. 2009CB623602)the National Natural Science Foundation of China (Grant No. U0634003)
文摘Several highly efficient iridium-complex polymer light-emitting devices （PLEDs） are fabricated, with a newly synthesized blue conjugated polymer, poly[（9,9-bis（4-（2-ethylhexyloxy）phenyl）-fluorene）-co-（3,7-dibenziothiene-S,S- dioxide15）] （PPF-3,TSO15）, chosen as host. High luminous efficiencies of 7.4 cd.A-1 and 27.4 cd.A-1 are achieved in red and green PLEDs, respectively, by optimizing the doping concentrations of red phosphorescent dye iridium bis（1- phenylisoquinoline） （acetylacetonate） （Ir（piq）） and green phosphorescent dye iridium tris（2-（4-tolyl）pyridinato-N, C2＇） （Ir（mppy）3）.Furthermore, highly efficient white PLEDs （WPLEDs） with the Commission Internationale de l＇Eclairage （CIE） coordinates of （0.35, 0.38） are successfully produced by carefully controlling the doping concentration of the irid- ium complex. The obtained WPLEDs show maximal efficiencies of 14.4 cd.A-1 and 10.1 lm.W-1, which are comparable to those of incandescent bulbs. Moreover, the electroluminescent spectrum of the white device with an initial luminance of about 1000 cd.m-2 is stable, subject to constant applied current stress, indicating that good device stability can be obtained in this system.
文摘A systematic study has been conducted on microcavity organic light emitting diodes(OLEDs)based on green,red and blue phosphorescent emitters to elucidate the microcavity effects for different color emitters.We found that the luminance output is determined by the reflectivity of the semitransparent electrode and the photopic response of the green,red and blue emitters.While the luminance enhancements of blue and red phosphorescent microcavity devices are small,a current efficiency as high as 224 cd A21 is obtained in the green phosphorescent microcavity OLEDs.
文摘Electroluminescence （EL） characteristics have been studied for a hybrid tandem white organic light emitting diode （OLED） with a blue emitting fluorescent EL1 unit based on BCzVBi and a yellow emitting phosphorescent EL2 unit based on （fbi）2Ir（acac）, where a MoO3 layer is inserted between EL1 and EL2 units as charge generation layer （CGL）. Maximum current and power efficiencies of 68.1 cd/A and 29.2 lm/W were obtained, respectively, while the current and power efficiencies at luminance of 1000 cd/m2 were 68.0 cd/A and 24.6 lm/W. The yellow emission appears from about 4.5 V firstly, while the blue emission starts to appear from about 5.4 V. It was found that charge generation from CGL of MoO3/NPB bilayer occurred at high voltages of above 5.4 V but not at low voltages below 5.2 V.
文摘采用真空热蒸镀方法以4,4′-bis(carbazol-9-yl)biphenyl(CBP)为主体材料、以bis[2-(4-tert-butylphenyl)benzothiazolato-N,C2′]iridium(acetylacetonate)[(t-bt)2Ir(acac)]磷光染料为掺杂剂构成黄色发光层,制备了高效白光的有机电致发光器件(OLEDs).OLEDs的器件结构为indium tin oxide(ITO)/N,N′-bis-(1-naphthyl)-N,N′-biphenyl-1,1′-biphenyl-4,4′-diamine(NPB)/CBP:(t-bt)2Ir(acac)/NPB/2,9-dimethyl-4,7-diphenyl-1,10-phenanthroline(BCP)/8-hydroxyquinoline aluminum(Alq3)/Mg∶Ag,从ITO阳极开始的第一层NPB为空穴传输层,第二层超薄的NPB为蓝色发光层,BCP为空穴阻挡层和激子阻挡层,Alq3为电子传输层.结果表明,器件电压在3V启亮,在16.5V时,器件的最高亮度达到15460cd·m-2;在4V时,器件达到最大流明效率为7.5lm·W-1,器件启亮后所发出的白光光谱在低电压时随电压变化有稍微的移动,但是都在白光范围内变化.在电压达到8V后Commission Internationale de l′Eclairage(国际照明委员会)(CIE)色坐标为(0.33,0.32),并且光谱及色坐标稳定,不随电压变化而改变,与最佳的白光坐标(0.33,0.33)几乎重合.同时,从机理上解释了光谱移动和效率衰减的原因,并探讨了载流子陷阱和能量传递的关系.
