Seven electron-deficient A_2 B type H_3-triarylcorroles have been synthesized and characterized. The solvent dependence of the electronic absorption and magnetic circular dichroism（MCD） spectra and a series of TD-DF...Seven electron-deficient A_2 B type H_3-triarylcorroles have been synthesized and characterized. The solvent dependence of the electronic absorption and magnetic circular dichroism（MCD） spectra and a series of TD-DFT calculations have been used to analyze trends in the electronic structures. Significant differences are observed in the optical spectra when solvents of differing polarity are used,which can be assigned to the effect of NH-tautomerism.展开更多
This paper reports on the n-type ZnS used as electron transport layer for the organic light-emitting diodes （OLEDs）. The naphthyl-substituted benzidine derivative （NPB） and tris （8-hydroxyquinoline） aluminium （...This paper reports on the n-type ZnS used as electron transport layer for the organic light-emitting diodes （OLEDs）. The naphthyl-substituted benzidine derivative （NPB） and tris （8-hydroxyquinoline） aluminium （Alq3） are used as the hole transport layer and the emitting layer respectively. The insertion of the n-type ZnS layer enhances the electron injection in the OLEDs. The study was carried out on OLEDs of structures： indium-tin-oxide （ITO）/NPB/Alq3/ZnS/LiF/AL, ITO/NPB/Alq3/LiF/AL and ITO/NPB/Alq3/AL. The luminance and efficiency of the device containing this electron transport layer are increased significantly over those obtained from conventional devices due to better carrier balance.展开更多
The advantages of nitride-based dual-wavelength light-emitting diodes （LEDs） with an InA1N electron blocking layer （EBL） are studied. The emission spectra, carrier concentration in the quantum wells （QWs）, energ...The advantages of nitride-based dual-wavelength light-emitting diodes （LEDs） with an InA1N electron blocking layer （EBL） are studied. The emission spectra, carrier concentration in the quantum wells （QWs）, energy band and internal quantum efficiency （IQE） are investigated. The simulation results indicate that an LED with an InA1N EBL performs better over a conventional LED with an A1GaN EBL and an LED with p-type-doped QW barriers. All of the advantages are due to the enhancement of carrier confinement and the lower electron leakage current. The simulation results also show that the efficiency droop is markedly improved and the luminous intensity is greatly enhanced when an InAlN EBL is used.展开更多
The electronic structures and optical properties of B3 ZnO series of Zn4X4-yMy（X ：O, S, Se or Te; M = N, Sb, C1 or I; y = 0 or 1） are studied by first-principles calculations using a pseudopotential plane-wave meth...The electronic structures and optical properties of B3 ZnO series of Zn4X4-yMy（X ：O, S, Se or Te; M = N, Sb, C1 or I; y = 0 or 1） are studied by first-principles calculations using a pseudopotential plane-wave method. The results show that Zn d-X p orbital interactions play an important role in the p-type doping tendency in zinc-based Ⅱ-Ⅵ semiconductors. In ZnX, with increasing atomic number of X, Zn d-X p orbital interactions decrease and Zn s-X p orbital interactions increase. Additionally, substituting group-V elements for X will reduce the Zn d-X p orbital interactions while substituting group-VII elements for X will increase the Zn d-X p orbital interactions. The results also show that group-V-doped ZnX and group-Ⅷ-doped ZnX exhibit different optical behaviours due to their different orbital interaction effects.展开更多
We have studied the cyclotron-resonance absorption and photoluminescence properties of the modulation n-doped ZnSe/BeTe/ZnSe type-Ⅱ quantum wells. It is shown that only the doped sample shows electron cyclotron-reson...We have studied the cyclotron-resonance absorption and photoluminescence properties of the modulation n-doped ZnSe/BeTe/ZnSe type-Ⅱ quantum wells. It is shown that only the doped sample shows electron cyclotron-resonance absorption. Also, the undoped sample shows two distinctive peaks in the spatially indirect photoluminescence spectra, and the doped one shows only one peak. The results reveal that the high concentration electrons accumulated in ZnSe quantum well layers from n-doped layers can tunnel through BeTe barrier from one well layer to the other. The electron concentration difference between these two well layers originating from the tunneling results in a new additional electric field, and can cancel out a built-in electric field as observed in the undoped structures.展开更多
Aluminium doped tin oxide films have been deposited onto glass substrates by using a simplified and low cost spray pyrolysis technique. The AI doping level varies between 0 and 30 at.% in the step of 5 at.%. The resis...Aluminium doped tin oxide films have been deposited onto glass substrates by using a simplified and low cost spray pyrolysis technique. The AI doping level varies between 0 and 30 at.% in the step of 5 at.%. The resistivity （p） is the minimum （0.38 Ω cm） for 20 at.% of AI doping. The possible mechanism behind the phenomenal zig-zag variation in resistivity with respect to AI doping is discussed in detail. The nature of conductivity changes from n-type to p-type when the AI doping level is 10 at.%. The results show that 20 at.% is the optimum doping level for good quality p-type SnO2：AI films suitable for transparent electronic devices.展开更多
基金financially supported by the National Natural Science Foundation of China(No.21171076)Natural Science Foundation of Jiangsu Province(No.BK20160499)to XL and WZ and an NRF of South Africa CSUR grant(uid:93627)to JM
文摘Seven electron-deficient A_2 B type H_3-triarylcorroles have been synthesized and characterized. The solvent dependence of the electronic absorption and magnetic circular dichroism（MCD） spectra and a series of TD-DFT calculations have been used to analyze trends in the electronic structures. Significant differences are observed in the optical spectra when solvents of differing polarity are used,which can be assigned to the effect of NH-tautomerism.
基金Project supported by the National Natural Science Foundation of China （Grant No 60476005）, the Scientific Research Foundation for Returned 0verseas Chinese Scholars, the State Education Ministry, the State Key Program for Basic Research of the Ministry of Science and Technology of China （Grant No 2003CB314707）, and the Key Project of National Natural Science Foundation of China （Grant No 50532090）.
文摘This paper reports on the n-type ZnS used as electron transport layer for the organic light-emitting diodes （OLEDs）. The naphthyl-substituted benzidine derivative （NPB） and tris （8-hydroxyquinoline） aluminium （Alq3） are used as the hole transport layer and the emitting layer respectively. The insertion of the n-type ZnS layer enhances the electron injection in the OLEDs. The study was carried out on OLEDs of structures： indium-tin-oxide （ITO）/NPB/Alq3/ZnS/LiF/AL, ITO/NPB/Alq3/LiF/AL and ITO/NPB/Alq3/AL. The luminance and efficiency of the device containing this electron transport layer are increased significantly over those obtained from conventional devices due to better carrier balance.
基金supported by the Project of Combination of Production and Research Guided by Ministry in 2009,China (Grant No. 2009B090300338)the Doctorate Foundation of the State Education Ministry of China (Grant No. 350163)the Crucial Field and Key Breakthrough Project of Guangdong Province and Hongkong,China (Grant No. 2007A010501008)
文摘The advantages of nitride-based dual-wavelength light-emitting diodes （LEDs） with an InA1N electron blocking layer （EBL） are studied. The emission spectra, carrier concentration in the quantum wells （QWs）, energy band and internal quantum efficiency （IQE） are investigated. The simulation results indicate that an LED with an InA1N EBL performs better over a conventional LED with an A1GaN EBL and an LED with p-type-doped QW barriers. All of the advantages are due to the enhancement of carrier confinement and the lower electron leakage current. The simulation results also show that the efficiency droop is markedly improved and the luminous intensity is greatly enhanced when an InAlN EBL is used.
基金Project supported by the National Natural Science Foundation of China （Grant No 10625416）.
文摘The electronic structures and optical properties of B3 ZnO series of Zn4X4-yMy（X ：O, S, Se or Te; M = N, Sb, C1 or I; y = 0 or 1） are studied by first-principles calculations using a pseudopotential plane-wave method. The results show that Zn d-X p orbital interactions play an important role in the p-type doping tendency in zinc-based Ⅱ-Ⅵ semiconductors. In ZnX, with increasing atomic number of X, Zn d-X p orbital interactions decrease and Zn s-X p orbital interactions increase. Additionally, substituting group-V elements for X will reduce the Zn d-X p orbital interactions while substituting group-VII elements for X will increase the Zn d-X p orbital interactions. The results also show that group-V-doped ZnX and group-Ⅷ-doped ZnX exhibit different optical behaviours due to their different orbital interaction effects.
基金Project supported by the National Natural Science Foundation of China (Grant Nos. 10844003 and 10874101)the Natural Science Foundation of Shandong Province,China (Grant No. Y2008A10)the National Basic Research Program of China (Grant No. 2009CB930503)
文摘We have studied the cyclotron-resonance absorption and photoluminescence properties of the modulation n-doped ZnSe/BeTe/ZnSe type-Ⅱ quantum wells. It is shown that only the doped sample shows electron cyclotron-resonance absorption. Also, the undoped sample shows two distinctive peaks in the spatially indirect photoluminescence spectra, and the doped one shows only one peak. The results reveal that the high concentration electrons accumulated in ZnSe quantum well layers from n-doped layers can tunnel through BeTe barrier from one well layer to the other. The electron concentration difference between these two well layers originating from the tunneling results in a new additional electric field, and can cancel out a built-in electric field as observed in the undoped structures.
基金Financial support from the University Grants Commission ofIndia through the Major Research Project(F.No.40-28/2011(SR))the DST Grant(D.O.No.SR/S2/CMP-35/2004)
文摘Aluminium doped tin oxide films have been deposited onto glass substrates by using a simplified and low cost spray pyrolysis technique. The AI doping level varies between 0 and 30 at.% in the step of 5 at.%. The resistivity （p） is the minimum （0.38 Ω cm） for 20 at.% of AI doping. The possible mechanism behind the phenomenal zig-zag variation in resistivity with respect to AI doping is discussed in detail. The nature of conductivity changes from n-type to p-type when the AI doping level is 10 at.%. The results show that 20 at.% is the optimum doping level for good quality p-type SnO2：AI films suitable for transparent electronic devices.
