The InGaN/GaN blue light emitting diode（LED） is numerically investigated using a triangular-shaped quantum well model,which involves analysis on its energy band,carrier concentration,overlap of electron and hole wav...The InGaN/GaN blue light emitting diode（LED） is numerically investigated using a triangular-shaped quantum well model,which involves analysis on its energy band,carrier concentration,overlap of electron and hole wave functions,radiative recombination rate,and internal quantum efficiency.The simulation results reveal that the InGaN/GaN blue light emitting diode with triangular quantum wells exhibits a higher radiative recombination rate than the conventional light emitting diode with rectangular quantum wells due to the enhanced overlap of electron and hole wave functions（above 90%） under the polarization field.Consequently,the efficiency droop is only 18% in the light emitting diode with triangular-shaped quantum wells,which is three times lower than that in a conventional LED.展开更多
In the present study, graphene photonic crystals are employed to enhance the light extraction efficiency（LEE） of two-color, red and blue, light-emitting diode（LED）. The transmission characteristics of one-dimensio...In the present study, graphene photonic crystals are employed to enhance the light extraction efficiency（LEE） of two-color, red and blue, light-emitting diode（LED）. The transmission characteristics of one-dimensional（1D） Fibonacci graphene photonic crystal LED（FGPC-LED） are investigated by using the transfer matrix method and the scaling study is presented. We analyzed the influence of period, thickness, and permittivity in the structure to enhance the LEE. The transmission spectrum of 1D FGPC has been optimized in detail. In addition, the effects of the angle of incidence and the state of polarization are investigated. As the main result, we found the optimum values of relevant parameters to enhance the extraction of red and blue light from an LED as well as provide perfect omnidirectional and high peak transmission filters for the TE and TM modes.展开更多
Copolymers containing alternating flexible aliphatic blocks and rigid poly (p-phenylenevinylene) (PPV) blocks were synthesized and characterized. It was found that the fluorescent intensity increases with increasing l...Copolymers containing alternating flexible aliphatic blocks and rigid poly (p-phenylenevinylene) (PPV) blocks were synthesized and characterized. It was found that the fluorescent intensity increases with increasing length of the flexible blocks. Bright blue-light emitting diodes were fabricated using PPV copolymers as electroluminescent layers. The devices show 190 cd/m2 light-emitting brightness at 460 nm and 15 V turn-on voltage. The effects of oxadiawle derivative PBD and tris(8-hydroxyquinoline) aluminum Alq3 electron-transporting layers on the luminance and stability of the devices are discussed.展开更多
基金Project supported by the National Natural Science Foundation of China (Grant Nos. 61076013,51102003,and 60990313)the National Basic Research Program of China (Grant No. 2012CB619304)the Specialized Research Fund for the Doctoral Program of Higher Education,China (Grant No. 20100001120014)
文摘The InGaN/GaN blue light emitting diode（LED） is numerically investigated using a triangular-shaped quantum well model,which involves analysis on its energy band,carrier concentration,overlap of electron and hole wave functions,radiative recombination rate,and internal quantum efficiency.The simulation results reveal that the InGaN/GaN blue light emitting diode with triangular quantum wells exhibits a higher radiative recombination rate than the conventional light emitting diode with rectangular quantum wells due to the enhanced overlap of electron and hole wave functions（above 90%） under the polarization field.Consequently,the efficiency droop is only 18% in the light emitting diode with triangular-shaped quantum wells,which is three times lower than that in a conventional LED.
文摘In the present study, graphene photonic crystals are employed to enhance the light extraction efficiency（LEE） of two-color, red and blue, light-emitting diode（LED）. The transmission characteristics of one-dimensional（1D） Fibonacci graphene photonic crystal LED（FGPC-LED） are investigated by using the transfer matrix method and the scaling study is presented. We analyzed the influence of period, thickness, and permittivity in the structure to enhance the LEE. The transmission spectrum of 1D FGPC has been optimized in detail. In addition, the effects of the angle of incidence and the state of polarization are investigated. As the main result, we found the optimum values of relevant parameters to enhance the extraction of red and blue light from an LED as well as provide perfect omnidirectional and high peak transmission filters for the TE and TM modes.
文摘Copolymers containing alternating flexible aliphatic blocks and rigid poly (p-phenylenevinylene) (PPV) blocks were synthesized and characterized. It was found that the fluorescent intensity increases with increasing length of the flexible blocks. Bright blue-light emitting diodes were fabricated using PPV copolymers as electroluminescent layers. The devices show 190 cd/m2 light-emitting brightness at 460 nm and 15 V turn-on voltage. The effects of oxadiawle derivative PBD and tris(8-hydroxyquinoline) aluminum Alq3 electron-transporting layers on the luminance and stability of the devices are discussed.
基金supported by the National Key Basic Research Program of China(973)(2015CB932202,2012CB933301)National Natural Science Foundation of China(61274065,51173081,61136003,BZ2010043,51372119,51172110,21304047,21373114,21003076)+7 种基金Innovation Team of the Ministry of Education of China(IRT1148)Ministry of Education Humanities and Social Science Research Projects,China(13YJCZH091)Natural Science Foundation of Jiangsu Province,China(BK20141424)Priority Academic Program Development of Jiangsu Provincial Higher Education Institutions,China(YX030001)Ordinary University Graduate Student Practical Innovation Projects of Jiangsu Province,China(SJLX15_0390)Pandeng Project of Nanjing University of Posts and Telecommunications,China(NY214085)Open Foundation from Jilin UniversityChina(IOSKL2015KF32)~~
