This work presents novel field emission organic light emitting diodes(FEOLEDs) with dynode,in which an organic EL light-emitting layer is used instead of an inorganic phosphor thin film in the field emission display(F...This work presents novel field emission organic light emitting diodes(FEOLEDs) with dynode,in which an organic EL light-emitting layer is used instead of an inorganic phosphor thin film in the field emission display(FED).The proposed FEOLEDs introduce field emission electrons into organic light emitting diodes(OLEDs),which exhibit a higher luminous efficiency than conventional OLED.The field emission electrons emitted from the carbon nanotubes(CNTs) cathode and to be amplified by impact the dynode in vacuum.These field emission electrons are injected into the multi-layer organic materials of OLED to increase the electron density.Additionally,the proposed FEOLED increase the luminance of OLED from 10 820 cd/m2 to 24 782 cd/m2 by raising the current density of OLED from an external electron source.The role of FEOLED is to add the quantity of electrons-holes pairs in OLED,which increase the exciton and further increase the luminous efficiency of OLED.Under the same operating current density,the FEOLED exhibits a higher luminous efficiency than that of OLED.展开更多
We report on white organic light-emitting diodes （WOLEDs） based on polyvinylcarbazole （PVK） doped with 1,1-bis（（di-4-tolylamino）phenyl）cyclohexane （TAPC） and perylene, and investigate the luminescence mechan...We report on white organic light-emitting diodes （WOLEDs） based on polyvinylcarbazole （PVK） doped with 1,1-bis（（di-4-tolylamino）phenyl）cyclohexane （TAPC） and perylene, and investigate the luminescence mechanism of the devices. The chromaticity of light emission can be tuned by adjusting the concentration of the dopants. White light with the Commission Internationale de L＇Eclairage （CIE） coordinates of （0.33, 0.34） is achieved by mixing the yellow electromer emission of TAPC and the blue monomer emission of perylene from the device ITO/PVK： TAPC： perylene （100：9：1 in wt.） （100 nm）/tris-（8-hydroxyquinoline aluminum （Alq3） （10 nm）/A1. The device exhibits a maximal luminance of 3727 cd/m2 and a current efficiency of 2 cd/A.展开更多
Organic light emitting diodes employing magnesium doped electron acceptor 3, 4, 9, 10 perylenetetracarboxylic dianhydride （Mg：PTCDA） as electron injection layer and silver as cathode were demonstrated. As compared ...Organic light emitting diodes employing magnesium doped electron acceptor 3, 4, 9, 10 perylenetetracarboxylic dianhydride （Mg：PTCDA） as electron injection layer and silver as cathode were demonstrated. As compared to Mg ： Ag cathode, the combination of the Mg ： PTCDA layer and silver provided enhanced electron injection into tris （8- quinolinolato） aluminium. The device with 1 ： 2 Mg ： PTCDA and Ag showed an increase of about 12% in the maximum current efficiency, mainly due to the improved hole-electron balance, and an increase of about 28% in the maximum power efficiency, as compared to the control device using Mg ： Ag cathode. The properties of Mg ： PTCDA composites were studied as well.展开更多
In this study the performance of organic light-emitting diodes （OLEDs） are enhanced significantly, which is based on dual electron transporting layers （13phen/CuPc）. By adjusting the thicknesses of Bphen and CuPc,...In this study the performance of organic light-emitting diodes （OLEDs） are enhanced significantly, which is based on dual electron transporting layers （13phen/CuPc）. By adjusting the thicknesses of Bphen and CuPc, the maximal luminescence, the maximal current efficiency, and the maximal power efficiency of the device reach 17570 cd/m^2 at 11 V, and 5.39 cd/A and 3.39 lm/W at 3.37 mA/cm^2 respectively, which are enhanced approximately by 33.4%, 39.3%, and 68.9%, respectively, compared with those of the device using Bphen only for an electron transporting layer. These results may provide some valuable references for improving the electron injection and the transportation of OLED.展开更多
By using p-bis（p - N, N-diphenyl-aminostyryl）benzene doped 2-tert-butyl-9, 10-bis-β-naphthyl）-anthracene as an emitting layer, we fabricate a high-efficiency and long-lifetime blue organic light emitting diode wit...By using p-bis（p - N, N-diphenyl-aminostyryl）benzene doped 2-tert-butyl-9, 10-bis-β-naphthyl）-anthracene as an emitting layer, we fabricate a high-efficiency and long-lifetime blue organic light emitting diode with a maximum external quantum efficiency of 6.19% and a stable lifetime at a high initial current density of 0.0375 A/cm2. We demonstrate that the change in the thicknesses of organic layers affects the operating voltage and luminous efficiency greater than the lifetime. The lifetime being independent of thickness is beneficial in achieving high-quality full-colour display devices and white lighting sources with multi-emitters.展开更多
Organic field-effect transistors(OFETs) based on organic micro-/nanocrystals have been widely reported with charge carrier mobility exceeding 1.0 cm^2V^(-1)s^(-1), demonstrating great potential for high-performance, l...Organic field-effect transistors(OFETs) based on organic micro-/nanocrystals have been widely reported with charge carrier mobility exceeding 1.0 cm^2V^(-1)s^(-1), demonstrating great potential for high-performance, low-cost organic electronic applications. However, fabrication of large-area organic micro-/nanocrystal arrays with consistent crystal growth direction has posed a significant technical challenge. Here, we describe a solution-processed dip-coating technique to grow large-area, aligned 9,10-bis(phenylethynyl) anthracene(BPEA) and 6,13-bis(triisopropylsilylethynyl) pentacene(TIPSPEN) single-crystalline nanoribbon arrays. The method is scalable to a 5 9 10 cm^2 wafer substrate, with around 60% of the wafer surface covered by aligned crystals. The quality of crystals can be easily controlled by tuning the dip-coating speed. Furthermore, OFETs based on well-aligned BPEA and TIPS-PEN single-crystalline nanoribbons were constructed.By optimizing channel lengths and using appropriate metallic electrodes, the BPEA and TIPS-PEN-based OFETs showed hole mobility exceeding 2.0 cm^2V^(-1)s^(-1)(average mobility 1.2 cm^2V^(-1)s^(-1)) and 3.0 cm^2V^(-1)s^(-1)(average mobility2.0 cm^2V^(-1)s^(-1)), respectively. They both have a high on/off ratio(I_(on)/I_(off))>10~9. The performance can well satisfy the requirements for light-emitting diodes driving.展开更多
The AlGaN-based deep ultraviolet light-emitting diodes（LED） with double electron blocking layers（d-EBLs） on both sides of the active region are investigated theoretically. They possess many excellent performances ...The AlGaN-based deep ultraviolet light-emitting diodes（LED） with double electron blocking layers（d-EBLs） on both sides of the active region are investigated theoretically. They possess many excellent performances compared with the conventional structure with only a single electron blocking layer, such as a higher recombination rate, improved light output power and internal quantum efficiency（IQE）. The reasons can be concluded as follows. On the one hand, the weakened electrostatic field within the quantum wells（QWs） enhances the electron–hole spatial overlap in QWs, and therefore increases the probability of radioactive recombination. On the other hand, the added n-AlGaN layer can not only prevent holes from overflowing into the n-side region but also act as another electron source, providing more electrons.展开更多
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
Thin films and thin film devices have a ubiquitous presence in numerous conventional and emerging technologies. This is because of the recent advances in nanotechnology, the development of functional and smart materia...Thin films and thin film devices have a ubiquitous presence in numerous conventional and emerging technologies. This is because of the recent advances in nanotechnology, the development of functional and smart materials,conducting polymers, molecular semiconductors, carbon nanotubes, and graphene, and the employment of unique properties of thin films and ultrathin films, such as high surface area, controlled nanostructure for effective charge transfer, and special physical and chemical properties, to develop new thin film devices. This paper is therefore intended to provide a concise critical review and research directions on most thin film devices, including thin film transistors, data storage memory, solar cells, organic light-emitting diodes, thermoelectric devices, smart materials, sensors, and actuators. The thin film devices may consist of organic, inorganic, and composite thin layers, and share similar functionality, properties, and fabrication routes. Therefore, due to the multidisciplinary nature of thin film devices, knowledge and advances already made in one area may be applicable to other similar areas. Owing to the importance of developing low-cost, scalable, and vacuum-free fabrication routes, this paper focuses on thin film devices that may be processed and deposited from solution.展开更多
We fabricate a kind of novel efficient blue fluorescent organic light emitting device（OLED） based on p-n heterojunctions composed of hole transporting layer（HTL） N,N ＇-bis（naphthalen-1-yl）-N,N ＇-bis（phenyl）-...We fabricate a kind of novel efficient blue fluorescent organic light emitting device（OLED） based on p-n heterojunctions composed of hole transporting layer（HTL） N,N ＇-bis（naphthalen-1-yl）-N,N ＇-bis（phenyl）-benzidine（NPB） and electron transporting layer（ETL） 4,7-diphnenyl-1,10-phenanthroline（BPhen）,into which a new blue material,DNCA（a derivation of N 6,N 6,N 12,N 12-tetrap-tolylchrysene-6,12-diamine）,is partially doped simultaneously,and double emitting layers are configured.With a turn-on voltage of 2.6 V at 1 cd/m 2,this type of OLED presents a maximum luminance efficiency（η max） of 8.83 cd/A at 5.818 mA/cm 2 and a maximum luminance of over 40000 cd/m 2.Meanwhile,the Commission Internationale De L＇Eclairage（CIE） coordinates of this device change slightly from（0.13,0.27） to（0.13,0.23） as the driving voltage increases from 3 V to 11 V.This improvement in the electroluminescent characteristics is attributed mainly to the ideal p-n heterojunction which can confine and distribute excitons evenly on two sides of the heterojunction interface so as to improve the carrier combination rate and expand the light-emitting region.展开更多
基金the I-Shou University,Taiwan,for financially supporting this research under Contract No.ISU99-01-06Taiwan Science Council under Contract No.NSC98-2218-E-214-001 and 98-2221-E-214-003-MY3
文摘This work presents novel field emission organic light emitting diodes(FEOLEDs) with dynode,in which an organic EL light-emitting layer is used instead of an inorganic phosphor thin film in the field emission display(FED).The proposed FEOLEDs introduce field emission electrons into organic light emitting diodes(OLEDs),which exhibit a higher luminous efficiency than conventional OLED.The field emission electrons emitted from the carbon nanotubes(CNTs) cathode and to be amplified by impact the dynode in vacuum.These field emission electrons are injected into the multi-layer organic materials of OLED to increase the electron density.Additionally,the proposed FEOLED increase the luminance of OLED from 10 820 cd/m2 to 24 782 cd/m2 by raising the current density of OLED from an external electron source.The role of FEOLED is to add the quantity of electrons-holes pairs in OLED,which increase the exciton and further increase the luminous efficiency of OLED.Under the same operating current density,the FEOLED exhibits a higher luminous efficiency than that of OLED.
基金Project supported by the National Natural Science Foundation of China (Grant Nos. 61177017,61125505,60978061,61077022,61036007,and 60877005)the 111 Project (Grant No. B08002)
文摘We report on white organic light-emitting diodes （WOLEDs） based on polyvinylcarbazole （PVK） doped with 1,1-bis（（di-4-tolylamino）phenyl）cyclohexane （TAPC） and perylene, and investigate the luminescence mechanism of the devices. The chromaticity of light emission can be tuned by adjusting the concentration of the dopants. White light with the Commission Internationale de L＇Eclairage （CIE） coordinates of （0.33, 0.34） is achieved by mixing the yellow electromer emission of TAPC and the blue monomer emission of perylene from the device ITO/PVK： TAPC： perylene （100：9：1 in wt.） （100 nm）/tris-（8-hydroxyquinoline aluminum （Alq3） （10 nm）/A1. The device exhibits a maximal luminance of 3727 cd/m2 and a current efficiency of 2 cd/A.
文摘Organic light emitting diodes employing magnesium doped electron acceptor 3, 4, 9, 10 perylenetetracarboxylic dianhydride （Mg：PTCDA） as electron injection layer and silver as cathode were demonstrated. As compared to Mg ： Ag cathode, the combination of the Mg ： PTCDA layer and silver provided enhanced electron injection into tris （8- quinolinolato） aluminium. The device with 1 ： 2 Mg ： PTCDA and Ag showed an increase of about 12% in the maximum current efficiency, mainly due to the improved hole-electron balance, and an increase of about 28% in the maximum power efficiency, as compared to the control device using Mg ： Ag cathode. The properties of Mg ： PTCDA composites were studied as well.
基金Project supported by the National Natural Science Foundation of China (Grant Nos. 60906022 and 60876046)the Tianjin Natural Science Foundation of China (Grant No. 10JCYBJC01100)
文摘In this study the performance of organic light-emitting diodes （OLEDs） are enhanced significantly, which is based on dual electron transporting layers （13phen/CuPc）. By adjusting the thicknesses of Bphen and CuPc, the maximal luminescence, the maximal current efficiency, and the maximal power efficiency of the device reach 17570 cd/m^2 at 11 V, and 5.39 cd/A and 3.39 lm/W at 3.37 mA/cm^2 respectively, which are enhanced approximately by 33.4%, 39.3%, and 68.9%, respectively, compared with those of the device using Bphen only for an electron transporting layer. These results may provide some valuable references for improving the electron injection and the transportation of OLED.
基金Project supported by the Science Fund of Science and Technology Commission of Shanghai Municipality,China (GrantNo. 10dz1140502)the Innovation Key Project of Education Commission of Shanghai Municipality,China (Grant No. 12ZZ091)the National Natural Science Foundation of China (Grant Nos. 61006005 and 61136003)
文摘By using p-bis（p - N, N-diphenyl-aminostyryl）benzene doped 2-tert-butyl-9, 10-bis-β-naphthyl）-anthracene as an emitting layer, we fabricate a high-efficiency and long-lifetime blue organic light emitting diode with a maximum external quantum efficiency of 6.19% and a stable lifetime at a high initial current density of 0.0375 A/cm2. We demonstrate that the change in the thicknesses of organic layers affects the operating voltage and luminous efficiency greater than the lifetime. The lifetime being independent of thickness is beneficial in achieving high-quality full-colour display devices and white lighting sources with multi-emitters.
基金supported by the National Basic Research Program of China(2013CB933500)National Natural Science Foundation of China(Grant Nos.61422403,51672180,51622306,21673151)+2 种基金Qing Lan ProjectCollaborative Innovation Center of Suzhou Nano Science and Technology(NANO-CIC)the Priority Academic Program Development of Jiangsu Higher Education Institutions(PAPD)
文摘Organic field-effect transistors(OFETs) based on organic micro-/nanocrystals have been widely reported with charge carrier mobility exceeding 1.0 cm^2V^(-1)s^(-1), demonstrating great potential for high-performance, low-cost organic electronic applications. However, fabrication of large-area organic micro-/nanocrystal arrays with consistent crystal growth direction has posed a significant technical challenge. Here, we describe a solution-processed dip-coating technique to grow large-area, aligned 9,10-bis(phenylethynyl) anthracene(BPEA) and 6,13-bis(triisopropylsilylethynyl) pentacene(TIPSPEN) single-crystalline nanoribbon arrays. The method is scalable to a 5 9 10 cm^2 wafer substrate, with around 60% of the wafer surface covered by aligned crystals. The quality of crystals can be easily controlled by tuning the dip-coating speed. Furthermore, OFETs based on well-aligned BPEA and TIPS-PEN single-crystalline nanoribbons were constructed.By optimizing channel lengths and using appropriate metallic electrodes, the BPEA and TIPS-PEN-based OFETs showed hole mobility exceeding 2.0 cm^2V^(-1)s^(-1)(average mobility 1.2 cm^2V^(-1)s^(-1)) and 3.0 cm^2V^(-1)s^(-1)(average mobility2.0 cm^2V^(-1)s^(-1)), respectively. They both have a high on/off ratio(I_(on)/I_(off))>10~9. The performance can well satisfy the requirements for light-emitting diodes driving.
基金Project supported by the Special Strategic Emerging Industries of Guangdong Province,China(Grant No.2012A080304006)the Major Scientific and Technological Projects of Zhongshan City,Guangdong Province,China(Grant No.2014A2FC204)the Forefront of Technology Innovation and Key Technology Projects of Guangdong Province,China(Grant Nos.2014B010121001 and 2014B010119004)
文摘The AlGaN-based deep ultraviolet light-emitting diodes（LED） with double electron blocking layers（d-EBLs） on both sides of the active region are investigated theoretically. They possess many excellent performances compared with the conventional structure with only a single electron blocking layer, such as a higher recombination rate, improved light output power and internal quantum efficiency（IQE）. The reasons can be concluded as follows. On the one hand, the weakened electrostatic field within the quantum wells（QWs） enhances the electron–hole spatial overlap in QWs, and therefore increases the probability of radioactive recombination. On the other hand, the added n-AlGaN layer can not only prevent holes from overflowing into the n-side region but also act as another electron source, providing more electrons.
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Research funding from the Shanghai Municipal Education Commission in the framework of the oriental scholar and distinguished professor designationfunding from the National Natural Science Foundation of China(NSFC)
文摘Thin films and thin film devices have a ubiquitous presence in numerous conventional and emerging technologies. This is because of the recent advances in nanotechnology, the development of functional and smart materials,conducting polymers, molecular semiconductors, carbon nanotubes, and graphene, and the employment of unique properties of thin films and ultrathin films, such as high surface area, controlled nanostructure for effective charge transfer, and special physical and chemical properties, to develop new thin film devices. This paper is therefore intended to provide a concise critical review and research directions on most thin film devices, including thin film transistors, data storage memory, solar cells, organic light-emitting diodes, thermoelectric devices, smart materials, sensors, and actuators. The thin film devices may consist of organic, inorganic, and composite thin layers, and share similar functionality, properties, and fabrication routes. Therefore, due to the multidisciplinary nature of thin film devices, knowledge and advances already made in one area may be applicable to other similar areas. Owing to the importance of developing low-cost, scalable, and vacuum-free fabrication routes, this paper focuses on thin film devices that may be processed and deposited from solution.
基金Project supported by the National Natural Science Foundation of China (Grant Nos. 60906022 and 60876046)the Tianjin Natural Science Foundation,China (Grant No. 10JCYBJC01100)
文摘We fabricate a kind of novel efficient blue fluorescent organic light emitting device（OLED） based on p-n heterojunctions composed of hole transporting layer（HTL） N,N ＇-bis（naphthalen-1-yl）-N,N ＇-bis（phenyl）-benzidine（NPB） and electron transporting layer（ETL） 4,7-diphnenyl-1,10-phenanthroline（BPhen）,into which a new blue material,DNCA（a derivation of N 6,N 6,N 12,N 12-tetrap-tolylchrysene-6,12-diamine）,is partially doped simultaneously,and double emitting layers are configured.With a turn-on voltage of 2.6 V at 1 cd/m 2,this type of OLED presents a maximum luminance efficiency（η max） of 8.83 cd/A at 5.818 mA/cm 2 and a maximum luminance of over 40000 cd/m 2.Meanwhile,the Commission Internationale De L＇Eclairage（CIE） coordinates of this device change slightly from（0.13,0.27） to（0.13,0.23） as the driving voltage increases from 3 V to 11 V.This improvement in the electroluminescent characteristics is attributed mainly to the ideal p-n heterojunction which can confine and distribute excitons evenly on two sides of the heterojunction interface so as to improve the carrier combination rate and expand the light-emitting region.
