In this paper,we report on the fabrication of a top-emitting electrophosphorescent p-i-n white organic lightemitting diode on the basis of a low-reflectivity Sm/Ag semi-transparent cathode together with a thickness-op...In this paper,we report on the fabrication of a top-emitting electrophosphorescent p-i-n white organic lightemitting diode on the basis of a low-reflectivity Sm/Ag semi-transparent cathode together with a thickness-optimized ZnS out-coupling layer.With a 24-nm out-coupling layer,the reflectivity of the cathode is reduced to 8% at 492 nm and the mean reflectivity is 24% in the visible area.By introducing an efficient electron blocking layer tris（1phenylpyrazolato,N,C2 ＇）iridium（III）（Ir（ppz） 3） to confine the exciton recombination area,the current efficiency and the colour stability of the device are effectively improved.A white emission with the Ir（ppz） 3 layer exhibits a maximum current efficiency of 9.8 cd/A at 8 V,and the Commission Internationale de L＇Eclairage（CIE） chromaticity coordinates are almost constant during a large voltage change of 6 V-11 V.There is almost no viewing angular dependence in the spectrum when the viewing angle is no more than 45,with a CIE x,y coordinate variation of only（±0.0025,±0.0008）.Even at a large viewing angle（75）,the CIE x,y coordinate change is as small as（±0.0087,±0.0013）.展开更多
Indium tin oxide （ITO） ultrathin films were prepared on glass substrate by DC （direct current） magnetron sputtering technique with the assistance of H2O vapor to avoid potential surface damage. The film properties...Indium tin oxide （ITO） ultrathin films were prepared on glass substrate by DC （direct current） magnetron sputtering technique with the assistance of H2O vapor to avoid potential surface damage. The film properties were characterized by X-ray diffraction （XRD） technique, four-point probe method and spectrophotometer. The results show that the deposited ITO film with introduced H2O during sputtering process was almost amorphous. The average visible light transmission of 100 nm ITO film was around 85% and square resistivity was below 80 Ω/square. The film was used as the transparent anode to fabricate an inverted top-emitting organic light-emitting diodes （IT-OLEDs） with the structure of glass substrate/Alq3 （40 nm）/NPB （15 nm）/CuPc （x nm）/ITO anode （100 nm）, where the film thickness of CuPc was optimized. It was found that the luminance of this IT-OLEDs was improved from 25 cd/m^2 to more than 527 cd/m^2 by increasing the thickness of CuPc, and luminance efficiency of 0.24 lm/W at 100 cd/m^2 was obtained, which indicated that the optimized thickness of CuPc layer was around 15 nm.展开更多
In this paper we report on a high-contrast top-emitting organic light-emitting device utilizing a moderate-reflection contrast-enhancement stack and a high refractive index anti-reflection layer.The contrast-enhanceme...In this paper we report on a high-contrast top-emitting organic light-emitting device utilizing a moderate-reflection contrast-enhancement stack and a high refractive index anti-reflection layer.The contrast-enhancement stack consists of a thin metal anode layer,a dielectric bilayer,and a thick metal underlayer.The resulting device,with the optimized contrast-enhancement stack thicknesses of Ni（30 nm）/MgF 2（62 nm）/ZnS（16 nm）/Ni（20 nm） and the 25-nm-thick ZnS anti-reflection layer,achieves a luminous reflectance of 4.01% in the visible region and a maximum current efficiency of 0.99 cd/A（at 62.3 mA/cm 2） together with a very stable chromaticity.The contrast ratio reaches 561：1 at an on-state brightness of 1000 cd/m^2 under an ambient illumination of 140 lx.In addition,the anti-reflection layer can also enhance the transmissivity of the cathode and improve light out-coupling by the effective restraint of microcavity effects.展开更多
It is still challenging to obtain broadband emission covering visible light spectrum as much as possible with negligible angular dependence. In this work, we demonstrate a low driving voltage top-emitting white organi...It is still challenging to obtain broadband emission covering visible light spectrum as much as possible with negligible angular dependence. In this work, we demonstrate a low driving voltage top-emitting white organic light-emitting diode （TEWOLED） based on complementary blue and yellow phosphor emitters with negligible angular dependence. The bottom copper anode with medium reflectance, which is compatible with the standard complementary metal oxide semiconductor （CMOS） technology below 0.13 μm, and the semitransparent multi- layer Cs2CO3/AI/Cu cathode as a top electrode, are introduced to realize high-performance TEWOLED. Our TEWOLED achieves high efficiencies of 15.4callA and 12.1 1m/W at a practical brightness of lO00cd/m2 at low voltage of 4 V.展开更多
ZnSeTe blue Cd-free quantum dot(QD)has emerged as a promising emitter for display applications due to its nontoxicity,tunable wavelength,and high efficiency.However,ZnSeTe-based quantum-dot light-emitting diodes(QLEDs...ZnSeTe blue Cd-free quantum dot(QD)has emerged as a promising emitter for display applications due to its nontoxicity,tunable wavelength,and high efficiency.However,ZnSeTe-based quantum-dot light-emitting diodes(QLEDs)usually exhibit unsaturated emissions with broad spectra.Herein,a top-emitting structure,equipped with a transparent indium-zinc-oxide(IZO)top electrode and an IZO phase tuning layer(PTL),is developed to modulate the emission spectra and the efficiency of the devices.Saturated blue emissions with color coordinates beyond Recommendation ITU-R BT.709(Rec.709)and near Rec.2020 standards are achieved.Moreover,benefiting from the improved outcoupling efficiency and the enhanced charge balance,the top-emitting QLED demonstrates a high external quantum efficiency of 15.14%,which is further improved to 18.16%by capping the devices with SiO2 nanospheres.Simulation analysis reveals that the surface plasmon polariton(SPP)losses are effectively reduced by applying a 100 nm PTL,leading to an outcoupling efficiency of 41.2%at a wavelength of 478 nm.Due to the simultaneously enhanced color saturation and efficiency,a high chroma efficiency(current efficiency/y coordinate in Commission Internationale de l'Eclairage chart)of 123 is obtained.The developed top-emitting architecture could enable the realization of efficient and saturated QLEDs for wide color gamut high-definition display applications.展开更多
Blue and white top-emitting organic light-emitting devices OLEDs with cavity effect have been fabricated. TBADN：3%DSAPh and Alq3：DCJTB/TBADN：TBPe/Alq3：C545 were used as emitting materials of microcavity OLEDs. On ...Blue and white top-emitting organic light-emitting devices OLEDs with cavity effect have been fabricated. TBADN：3%DSAPh and Alq3：DCJTB/TBADN：TBPe/Alq3：C545 were used as emitting materials of microcavity OLEDs. On a patterned glass substrate, silver was deposited as re？ective anode, and copper phthalocyanine （CuPc） layer as HIL and 4’-bis[N-（1-Naphthyl）- N-phenyl-amino]biphenyl （NPB） layer as HTL were made. Al/Ag thin films were made as semi-transparent cathode with a transmittance of about 30%. By changing the thickness of indium tin oxide ITO, deep blue with Commission Internationale de L’Eclairage chromaticity coordinates （CIEx,y） of （0.141, 0.049） was obtained on TBADN：3%DSAPh devices, and different color（red, blue and green）was obtained on Alq3：DCJTB/TBADN：TBPe/Alq3：C545 devices, full width at half maxima （FWHM） was only 17 nm. The spectral intensity and FWHM of emission in cavity devices have also been studied.展开更多
We have demonstrated a high perlbrmance top-emitting organic light-emitting diode （TEOLED） achieving a brightness of 1000 cd/m^2 at a low voltage of 3.4 V, a power efficiency of 55.2 lm/W at a brightness of 611cd/m^...We have demonstrated a high perlbrmance top-emitting organic light-emitting diode （TEOLED） achieving a brightness of 1000 cd/m^2 at a low voltage of 3.4 V, a power efficiency of 55.2 lm/W at a brightness of 611cd/m^2. and a low efficiency roll-off 5.1% calculated from the maximum efficiency value to that of 5000 cd/m^2. Such im- proved properties are controlled by electron injection from 7-diphenyl-1,10-phenanthroline （BPhen） into and trans- port by the 2,4,6-tris[3＇-（pyridin-3-yl）biphenyl-3-yl]-l,3,5-triazine （TmPPPyTz） layer along with hole injection from 4,4＇,4＂-tris（N-carbazolyl）diphenylamine （TcTa） directly into the fac-tris（2-phenylpyridine）iridium [lr（ppy）3] highest occupied molecular level （HOMO）, leading to direct carrier recombination and excitons formation on the phosphor dopants. Eventually we integrated our high performance TEOLEDs on complementary metal oxide semi- conductor （CMOS） substrates to realize super video graphics array （SVGA） OLED microdisplays.展开更多
Emission characteristics of top emitting organic light-emitting devices （TOLEDs） with Ag as reflective anode, Al/Ag as semitransparent cathode and 90 160 nm [N-（1-naphthyl）-N-phenyl-amino] biphenyl/tris-（8-hydrox...Emission characteristics of top emitting organic light-emitting devices （TOLEDs） with Ag as reflective anode, Al/Ag as semitransparent cathode and 90 160 nm [N-（1-naphthyl）-N-phenyl-amino] biphenyl/tris-（8-hydroxy quinoline） aluminum （NPB/Alq3） sandwiched in the electrodes are examined. The electroluminescence （EL） spectra of the TOLEDs are simulated based on the Fabry-Perot cavity theory. And the resonant modes in cavity structure of TOLEDs is discussed and clarified which can accurately describe the work principle of the devices. A fairly good match between calculated values and experimental data is achieved at different emission colors from bluish green to orange.展开更多
Natural resource scarcity,fossil fuel energy consumption,and total greenhouse gas emissions are critical issues that require immediate attention.With the global population steadily increasing and economies expanding,t...Natural resource scarcity,fossil fuel energy consumption,and total greenhouse gas emissions are critical issues that require immediate attention.With the global population steadily increasing and economies expanding,the demand for natural resources,particularly fossil fuels,has experienced an unprecedented surge.This surge in consumption is directly linked to the alarming rise in greenhouse gas emissions.The study examines the nexus between agricultural nitrous oxide emissions and natural resource scarcity,taking into account the dynamics of agriculture,forestry,fishing value addition,fossil fuels,and total greenhouse gas emissions in top-emitting countries between 1971 and 2020.Natural resource scarcity positively correlates with agriculture,forestry,fishing,fossil fuel energy consumption,and total greenhouse gas emissions.There is a decrease in natural resource scarcity in countries that emit agricultural nitrous oxide,forestry,fishing emissions,fossil fuel energy consumption,and greenhouse gas emissions.Policy-makers may promote sustainable development,mitigate climate change,and ensure the longterm viability of agricultural systems by addressing the dynamics of agriculture,forestry,and fishing value addition in top-emitting countries.Through strategic policy interventions,supported by technology transfer,capacity building,and market-based instruments,the agricultural,forestry,and fishing sector can achieve a more sustainable future while addressing the challenges of natural resource scarcity.展开更多
基金Project supported by the Science Fund of the Ministry of Science and Technology,China (Grant No. 2009CB930600)the National Natural Science Foundation of China (Grants Nos. 60907047,61274065,and 60977024)+4 种基金the Key Project of the Chinese Ministryof Education (Grants Nos. 104246 and 707032)the Research Fund for the Doctoral Program of Higher Education Institutions,China (Grant Nos. 20093223120003 and 20093223110003)the Natural Science Foundation of Jiangsu Province and the Higher Education Institutions of Jiangsu Province,China (Grants Nos. BK2009423,SJ209003,10KJB510013,and 11KJD510003)the Fok Ying-Tong Education Foundation,China (Grant No. 111051)the "Qing Lan" Program of Jiangsu Province and the "Pandeng"Project of Nanjing University of Posts and Telecommunications,China (Grant Nos. NY210015,NY211069,and NY210040)
文摘In this paper,we report on the fabrication of a top-emitting electrophosphorescent p-i-n white organic lightemitting diode on the basis of a low-reflectivity Sm/Ag semi-transparent cathode together with a thickness-optimized ZnS out-coupling layer.With a 24-nm out-coupling layer,the reflectivity of the cathode is reduced to 8% at 492 nm and the mean reflectivity is 24% in the visible area.By introducing an efficient electron blocking layer tris（1phenylpyrazolato,N,C2 ＇）iridium（III）（Ir（ppz） 3） to confine the exciton recombination area,the current efficiency and the colour stability of the device are effectively improved.A white emission with the Ir（ppz） 3 layer exhibits a maximum current efficiency of 9.8 cd/A at 8 V,and the Commission Internationale de L＇Eclairage（CIE） chromaticity coordinates are almost constant during a large voltage change of 6 V-11 V.There is almost no viewing angular dependence in the spectrum when the viewing angle is no more than 45,with a CIE x,y coordinate variation of only（±0.0025,±0.0008）.Even at a large viewing angle（75）,the CIE x,y coordinate change is as small as（±0.0087,±0.0013）.
基金supported by the National Natural Science Foundation of China under Grants No.60425101Young Excellence Project of University of Electronic Science and Technology of China(UESTC-060206)project.
文摘Indium tin oxide （ITO） ultrathin films were prepared on glass substrate by DC （direct current） magnetron sputtering technique with the assistance of H2O vapor to avoid potential surface damage. The film properties were characterized by X-ray diffraction （XRD） technique, four-point probe method and spectrophotometer. The results show that the deposited ITO film with introduced H2O during sputtering process was almost amorphous. The average visible light transmission of 100 nm ITO film was around 85% and square resistivity was below 80 Ω/square. The film was used as the transparent anode to fabricate an inverted top-emitting organic light-emitting diodes （IT-OLEDs） with the structure of glass substrate/Alq3 （40 nm）/NPB （15 nm）/CuPc （x nm）/ITO anode （100 nm）, where the film thickness of CuPc was optimized. It was found that the luminance of this IT-OLEDs was improved from 25 cd/m^2 to more than 527 cd/m^2 by increasing the thickness of CuPc, and luminance efficiency of 0.24 lm/W at 100 cd/m^2 was obtained, which indicated that the optimized thickness of CuPc layer was around 15 nm.
基金Project supported by the State Key Development Program for Basic Research of China (Grant No. 2009CB930600)the National Natural Science Foundation of China (Grant Nos. 60907047,61274065,60977024,21101095,20974046,21003076,51173081,and 61136003)+3 种基金the Specialized Research Foundation for the Doctoral Program of Higher Education,China (Grant No. 20093223120003)the Natural Science Foundation of Institutions of Higher Education of Jiangsu Province,China (Grant Nos. SJ209003,09KJB150009,10KJB510013,and TJ209035)the "Qing Lan" Program of Jiangsu Province,Chinathe Program of Nanjing University of Posts and Telecommunications,China (Grant Nos. NY210015,NY211069,and NY210040)
文摘In this paper we report on a high-contrast top-emitting organic light-emitting device utilizing a moderate-reflection contrast-enhancement stack and a high refractive index anti-reflection layer.The contrast-enhancement stack consists of a thin metal anode layer,a dielectric bilayer,and a thick metal underlayer.The resulting device,with the optimized contrast-enhancement stack thicknesses of Ni（30 nm）/MgF 2（62 nm）/ZnS（16 nm）/Ni（20 nm） and the 25-nm-thick ZnS anti-reflection layer,achieves a luminous reflectance of 4.01% in the visible region and a maximum current efficiency of 0.99 cd/A（at 62.3 mA/cm 2） together with a very stable chromaticity.The contrast ratio reaches 561：1 at an on-state brightness of 1000 cd/m^2 under an ambient illumination of 140 lx.In addition,the anti-reflection layer can also enhance the transmissivity of the cathode and improve light out-coupling by the effective restraint of microcavity effects.
基金Supported by the National Basic Research Program of China under Grant No 2010CB327701the National Natural Science Foundation of China under Grant No 61275033
文摘It is still challenging to obtain broadband emission covering visible light spectrum as much as possible with negligible angular dependence. In this work, we demonstrate a low driving voltage top-emitting white organic light-emitting diode （TEWOLED） based on complementary blue and yellow phosphor emitters with negligible angular dependence. The bottom copper anode with medium reflectance, which is compatible with the standard complementary metal oxide semiconductor （CMOS） technology below 0.13 μm, and the semitransparent multi- layer Cs2CO3/AI/Cu cathode as a top electrode, are introduced to realize high-performance TEWOLED. Our TEWOLED achieves high efficiencies of 15.4callA and 12.1 1m/W at a practical brightness of lO00cd/m2 at low voltage of 4 V.
基金supported by the National Natural Science Foundation of China(No.62174075)Shenzhen Science and Technology Program(Nos.JCYJ20210324105400002 and JCYJ20220530113809022)the Guangdong University Research Program(No.2020ZDZX3062).
文摘ZnSeTe blue Cd-free quantum dot(QD)has emerged as a promising emitter for display applications due to its nontoxicity,tunable wavelength,and high efficiency.However,ZnSeTe-based quantum-dot light-emitting diodes(QLEDs)usually exhibit unsaturated emissions with broad spectra.Herein,a top-emitting structure,equipped with a transparent indium-zinc-oxide(IZO)top electrode and an IZO phase tuning layer(PTL),is developed to modulate the emission spectra and the efficiency of the devices.Saturated blue emissions with color coordinates beyond Recommendation ITU-R BT.709(Rec.709)and near Rec.2020 standards are achieved.Moreover,benefiting from the improved outcoupling efficiency and the enhanced charge balance,the top-emitting QLED demonstrates a high external quantum efficiency of 15.14%,which is further improved to 18.16%by capping the devices with SiO2 nanospheres.Simulation analysis reveals that the surface plasmon polariton(SPP)losses are effectively reduced by applying a 100 nm PTL,leading to an outcoupling efficiency of 41.2%at a wavelength of 478 nm.Due to the simultaneously enhanced color saturation and efficiency,a high chroma efficiency(current efficiency/y coordinate in Commission Internationale de l'Eclairage chart)of 123 is obtained.The developed top-emitting architecture could enable the realization of efficient and saturated QLEDs for wide color gamut high-definition display applications.
基金supported by the National Natural Science Foundation of China (No. 60477014)
文摘Blue and white top-emitting organic light-emitting devices OLEDs with cavity effect have been fabricated. TBADN：3%DSAPh and Alq3：DCJTB/TBADN：TBPe/Alq3：C545 were used as emitting materials of microcavity OLEDs. On a patterned glass substrate, silver was deposited as re？ective anode, and copper phthalocyanine （CuPc） layer as HIL and 4’-bis[N-（1-Naphthyl）- N-phenyl-amino]biphenyl （NPB） layer as HTL were made. Al/Ag thin films were made as semi-transparent cathode with a transmittance of about 30%. By changing the thickness of indium tin oxide ITO, deep blue with Commission Internationale de L’Eclairage chromaticity coordinates （CIEx,y） of （0.141, 0.049） was obtained on TBADN：3%DSAPh devices, and different color（red, blue and green）was obtained on Alq3：DCJTB/TBADN：TBPe/Alq3：C545 devices, full width at half maxima （FWHM） was only 17 nm. The spectral intensity and FWHM of emission in cavity devices have also been studied.
文摘We have demonstrated a high perlbrmance top-emitting organic light-emitting diode （TEOLED） achieving a brightness of 1000 cd/m^2 at a low voltage of 3.4 V, a power efficiency of 55.2 lm/W at a brightness of 611cd/m^2. and a low efficiency roll-off 5.1% calculated from the maximum efficiency value to that of 5000 cd/m^2. Such im- proved properties are controlled by electron injection from 7-diphenyl-1,10-phenanthroline （BPhen） into and trans- port by the 2,4,6-tris[3＇-（pyridin-3-yl）biphenyl-3-yl]-l,3,5-triazine （TmPPPyTz） layer along with hole injection from 4,4＇,4＂-tris（N-carbazolyl）diphenylamine （TcTa） directly into the fac-tris（2-phenylpyridine）iridium [lr（ppy）3] highest occupied molecular level （HOMO）, leading to direct carrier recombination and excitons formation on the phosphor dopants. Eventually we integrated our high performance TEOLEDs on complementary metal oxide semi- conductor （CMOS） substrates to realize super video graphics array （SVGA） OLED microdisplays.
基金Project supported by the Science and Technology Commission of Shanghai Municipality(Grant No.09ZR1411900)the National High-Technology Research and Development Program of China(Grant No.2010AA03A337)
文摘Emission characteristics of top emitting organic light-emitting devices （TOLEDs） with Ag as reflective anode, Al/Ag as semitransparent cathode and 90 160 nm [N-（1-naphthyl）-N-phenyl-amino] biphenyl/tris-（8-hydroxy quinoline） aluminum （NPB/Alq3） sandwiched in the electrodes are examined. The electroluminescence （EL） spectra of the TOLEDs are simulated based on the Fabry-Perot cavity theory. And the resonant modes in cavity structure of TOLEDs is discussed and clarified which can accurately describe the work principle of the devices. A fairly good match between calculated values and experimental data is achieved at different emission colors from bluish green to orange.
文摘Natural resource scarcity,fossil fuel energy consumption,and total greenhouse gas emissions are critical issues that require immediate attention.With the global population steadily increasing and economies expanding,the demand for natural resources,particularly fossil fuels,has experienced an unprecedented surge.This surge in consumption is directly linked to the alarming rise in greenhouse gas emissions.The study examines the nexus between agricultural nitrous oxide emissions and natural resource scarcity,taking into account the dynamics of agriculture,forestry,fishing value addition,fossil fuels,and total greenhouse gas emissions in top-emitting countries between 1971 and 2020.Natural resource scarcity positively correlates with agriculture,forestry,fishing,fossil fuel energy consumption,and total greenhouse gas emissions.There is a decrease in natural resource scarcity in countries that emit agricultural nitrous oxide,forestry,fishing emissions,fossil fuel energy consumption,and greenhouse gas emissions.Policy-makers may promote sustainable development,mitigate climate change,and ensure the longterm viability of agricultural systems by addressing the dynamics of agriculture,forestry,and fishing value addition in top-emitting countries.Through strategic policy interventions,supported by technology transfer,capacity building,and market-based instruments,the agricultural,forestry,and fishing sector can achieve a more sustainable future while addressing the challenges of natural resource scarcity.
