A new rare earth complex Tb（p-CIBA）3phen was synthesized and introduced into organic tight emitting devices （OLEDs） as emitting material. The Tb（p-CIBA）3phen was doped into PVK to improve the filmforming and hol...A new rare earth complex Tb（p-CIBA）3phen was synthesized and introduced into organic tight emitting devices （OLEDs） as emitting material. The Tb（p-CIBA）3phen was doped into PVK to improve the filmforming and hole-transporting property. Two kinds of devices were fabricated. The device structure is as the following. Single-layer device： ITO/PVK： Tb （p-CIBA） 3 phen /LiF/Al; double-layer device： ITO/PVK： Tb（p-CIBA）3phen/AIQ/LiF/AI. The performances of both devices were investigated carefully. We found that the emission of PVK was completely restrained,and only the green emission was observed from the electroluminescence. The full width at half maximum （FWHM） was less than 10 nm. The highest EL brighthess of the single-layer device is 25.4 cd/cm^2 at a fixed bias of 18 V,and the highest EL brightness of the double-layer device reaches 234.8 cd/cm^2 at a voltage of 20 V.展开更多
An energy-saving light-emitting-diode(LED) street lamp was conducted. Based on the simulation by optical software TracePro,a physical street lamp system including 600 white LEDs was achieved. This system was operated ...An energy-saving light-emitting-diode(LED) street lamp was conducted. Based on the simulation by optical software TracePro,a physical street lamp system including 600 white LEDs was achieved. This system was operated under a constant current of 20 mA for each unit,and the electric power consumption of the whole lamp was only 42 W. Experimental results demonstrated that the total average illuminance reached 8.8 lx and the overall uniformity was 0.370 for a 30-m-long and 10-m-wide test area at a height of 8 m,which is fully acceptable for the current standard for sub-main road.展开更多
A simple model of the graded heterojunction in AlGaInP compound semiconductors was introduced to analyze the band profile. The band profiles are analyzed with the different grading ways but the same grading length and...A simple model of the graded heterojunction in AlGaInP compound semiconductors was introduced to analyze the band profile. The band profiles are analyzed with the different grading ways but the same grading length and under the different doping densities. The effect of the different grading lengths on the surplus of the potential of the spike to the potential of N region are also analyzed under the different doping densities.Through the experiments,it proves that the performances of high brightness light emitting diodes can be improved by the effects of the graded heterojunction.展开更多
Metal halide perovskite light emitting diodes(PeLEDs)have recently experienced rapid development due to the tunable emission wavelengths,narrow emission linewidth and low material cost.To achieve stateof-the-art perfo...Metal halide perovskite light emitting diodes(PeLEDs)have recently experienced rapid development due to the tunable emission wavelengths,narrow emission linewidth and low material cost.To achieve stateof-the-art performance,the high photoluminescence quantum yield(PLQY)of the active emission layer,the balanced charge injection,and the optimized optical extraction should be considered simultaneously.Multiple chemical passivation strategies have been provided as controllable and efficient methods to improve the PLQY of the perovskite layer.However,high luminance under large injection current and high external quantum efficiency(EQE)can hardly be achieved due to Auger recombination at high carrier density.Here,we decreased the electron injection barrier by tuning the Fermi-level of the perovskite,leading to a reduced turn on voltage.Through molecular doping of the hole injection material,a more balanced hole injection was achieved.At last,a device with modified charge injection realizes high luminance and quantum efficiency simultaneously.The best device exhibits luminance of 55,000 cd m^-2 EQE of 8.02%at the working voltage of 2.65 V,current density of 115 mA cm^-2,and shows EQE T50 stability around 160 min at 100 mA cm^-2 injection current density.展开更多
We demonstrate high-brightness blue organic light emitting diodes(OLEDs) using two types of guest-host systems. A series of blue OLEDs were fabricated using three organic emitters of dibenz anthracene(perylene), di(4-...We demonstrate high-brightness blue organic light emitting diodes(OLEDs) using two types of guest-host systems. A series of blue OLEDs were fabricated using three organic emitters of dibenz anthracene(perylene), di(4-fluorophenyl) amino-di(styryl) biphenyl(DSB) and 4,4'-bis[2-(9-ethyl-3-carbazolyl)vinyl]biphenyl(BCzV Bi) doped into two hosting materials of 4,4'-bis(9-carbazolyl) biphenyl(CBP) and 2-(4-biphenylyl)-5(4-tert-butyl-phenyl)-1,3,4-oxadiazole(PBD) as blue emitting layers, respectively. We achieve three kinds of devices with colors of deep-blue, pure-blue and sky-blue with the Commission Internationale de L'Eclairage(CIE) coordinates of(0.16, 0.10),(0.15, 0.15) and(0.17, 0.24), respectively, by employing PBD as host material. In addition, we present a microcavity device using the PBD guest-host system and achieve high-purity blue devices with narrowed spectrum.展开更多
基金Supported by National Natural Science Foundation of China (90201004) Beijing Science and Technology Foundation ( H030430020410)Hebei provice Natural Science Foundation (203148) .
文摘A new rare earth complex Tb（p-CIBA）3phen was synthesized and introduced into organic tight emitting devices （OLEDs） as emitting material. The Tb（p-CIBA）3phen was doped into PVK to improve the filmforming and hole-transporting property. Two kinds of devices were fabricated. The device structure is as the following. Single-layer device： ITO/PVK： Tb （p-CIBA） 3 phen /LiF/Al; double-layer device： ITO/PVK： Tb（p-CIBA）3phen/AIQ/LiF/AI. The performances of both devices were investigated carefully. We found that the emission of PVK was completely restrained,and only the green emission was observed from the electroluminescence. The full width at half maximum （FWHM） was less than 10 nm. The highest EL brighthess of the single-layer device is 25.4 cd/cm^2 at a fixed bias of 18 V,and the highest EL brightness of the double-layer device reaches 234.8 cd/cm^2 at a voltage of 20 V.
文摘An energy-saving light-emitting-diode(LED) street lamp was conducted. Based on the simulation by optical software TracePro,a physical street lamp system including 600 white LEDs was achieved. This system was operated under a constant current of 20 mA for each unit,and the electric power consumption of the whole lamp was only 42 W. Experimental results demonstrated that the total average illuminance reached 8.8 lx and the overall uniformity was 0.370 for a 30-m-long and 10-m-wide test area at a height of 8 m,which is fully acceptable for the current standard for sub-main road.
文摘A simple model of the graded heterojunction in AlGaInP compound semiconductors was introduced to analyze the band profile. The band profiles are analyzed with the different grading ways but the same grading length and under the different doping densities. The effect of the different grading lengths on the surplus of the potential of the spike to the potential of N region are also analyzed under the different doping densities.Through the experiments,it proves that the performances of high brightness light emitting diodes can be improved by the effects of the graded heterojunction.
基金in part supported by Research Grants Council of Hong Kong,particularly,via Grant Nos.Ao E/P-03/08,T23-407/13-N,Ao E/P-02/12,14207515,14204616CUHK Group Research Scheme,and ITS/088/17 by Innovation and Technology Commission,Hong Kong SAR Governmentthe National Natural Science Foundation of China for the support,particularly,via Grant No.61229401。
文摘Metal halide perovskite light emitting diodes(PeLEDs)have recently experienced rapid development due to the tunable emission wavelengths,narrow emission linewidth and low material cost.To achieve stateof-the-art performance,the high photoluminescence quantum yield(PLQY)of the active emission layer,the balanced charge injection,and the optimized optical extraction should be considered simultaneously.Multiple chemical passivation strategies have been provided as controllable and efficient methods to improve the PLQY of the perovskite layer.However,high luminance under large injection current and high external quantum efficiency(EQE)can hardly be achieved due to Auger recombination at high carrier density.Here,we decreased the electron injection barrier by tuning the Fermi-level of the perovskite,leading to a reduced turn on voltage.Through molecular doping of the hole injection material,a more balanced hole injection was achieved.At last,a device with modified charge injection realizes high luminance and quantum efficiency simultaneously.The best device exhibits luminance of 55,000 cd m^-2 EQE of 8.02%at the working voltage of 2.65 V,current density of 115 mA cm^-2,and shows EQE T50 stability around 160 min at 100 mA cm^-2 injection current density.
基金supported by the National Natural Science Foundation of China(Nos.51505270 and 61504077)the National Basic Research Program of China(No.2015CB655005)the Project of Science and Technology Commission of Shanghai Municipality(No.15590500500)
文摘We demonstrate high-brightness blue organic light emitting diodes(OLEDs) using two types of guest-host systems. A series of blue OLEDs were fabricated using three organic emitters of dibenz anthracene(perylene), di(4-fluorophenyl) amino-di(styryl) biphenyl(DSB) and 4,4'-bis[2-(9-ethyl-3-carbazolyl)vinyl]biphenyl(BCzV Bi) doped into two hosting materials of 4,4'-bis(9-carbazolyl) biphenyl(CBP) and 2-(4-biphenylyl)-5(4-tert-butyl-phenyl)-1,3,4-oxadiazole(PBD) as blue emitting layers, respectively. We achieve three kinds of devices with colors of deep-blue, pure-blue and sky-blue with the Commission Internationale de L'Eclairage(CIE) coordinates of(0.16, 0.10),(0.15, 0.15) and(0.17, 0.24), respectively, by employing PBD as host material. In addition, we present a microcavity device using the PBD guest-host system and achieve high-purity blue devices with narrowed spectrum.
