The nanorod structure is an alternative scheme to develop high-efficiency deep ultraviolet light-emitting diodes(DUV LEDs). In this paper, we first report the electrically injected 274-nm AlGaN nanorod array DUV LEDs ...The nanorod structure is an alternative scheme to develop high-efficiency deep ultraviolet light-emitting diodes(DUV LEDs). In this paper, we first report the electrically injected 274-nm AlGaN nanorod array DUV LEDs fabricated by the nanosphere lithography and dry-etching technique. Nanorod DUV LED devices with good electrical properties are successfully realized. Compared to planar DUV LEDs, nanorod DUV LEDs present>2.5 times improvement in light output power and external quantum efficiency. The internal quantum efficiency of nanorod LEDs increases by 1.2 times due to the transformation of carriers from the exciton to the free electron–hole, possibly driven by the interface state effect of the nanorod sidewall surface. In addition, the nanorod array significantly facilitates photons escaping from the interior of LEDs along the vertical direction, contributing to improved light extraction efficiency. A three-dimensional finite-different time-domain simulation is performed to analyze further in detail the TE-and TM-polarized photon extraction mechanisms of the nanostructure. Our results demonstrate the nanorod structure is a good candidate for high-efficiency DUV emitters.展开更多
The development of highly efficient and durable oxygen evolution reaction(OER)catalysts for seawater electrolysis is of great importance for applications.Here,an amorphous FeMoO_(4) nanorod array on Ni foam is reporte...The development of highly efficient and durable oxygen evolution reaction(OER)catalysts for seawater electrolysis is of great importance for applications.Here,an amorphous FeMoO_(4) nanorod array on Ni foam is reported as a highly active OER electrocatalyst in alkaline seawater,requiring only overpotentials of 303 and 332 mV to achieve 100 and 300 mA·cm^(-2),respectively.Moreover,it shows strong long-term electrochemical durability for at least 50 h.展开更多
Low optical absorption and photocorrosion are two crucial issues limiting the practical applications of zinc oxide(ZnO)-based photocatalysts.In this paper,we report the fabrication of graphitic-carbon-mediated ZnO nan...Low optical absorption and photocorrosion are two crucial issues limiting the practical applications of zinc oxide(ZnO)-based photocatalysts.In this paper,we report the fabrication of graphitic-carbon-mediated ZnO nanorod arrays(NRAs)with enhanced photocatalytic activity and photostability for CO2 reduction under visible light irradiation.ZnO NRA/C-x(x=005,01,02,and 03)nanohybrids are prepared by calcining pre-synthesized ZnO NRAs with different amounts of glucose(0.05,0.1,0.2,and 0.3 g)as a carbon source via a hydrothermal method.X-ray photoelectron spectroscopy reveals that the obtained ZnO NRA/C-x nanohybrids are imparted with the effects of both carbon doping and carbon coating,as evidenced by the detected C-O-Zn bond and the C-C,C-O and C=O bonds,respectively.While the basic structure of ZnO remains unchanged,the UV-Vis absorption spectra show increased absorbance owing to the carbon doping effect in the ZnO NRA/C-x nanohybrids.The photoluminescence(PL)intensities of ZnO NRA/C-x nanohybrids are lower than that of bare ZnO NRA,indicating that the graphitic carbon layer coated on the surface of the ZnO NRA significantly enhances the charge carrier separation and transport,which in turn enhances the photoelectrochemical property and photocatalytic activity of the ZnO NRA/C-x nanohybrids for CO2 reduction.More importantly,a long-term reaction of photocatalytic CO2 reduction demonstrates that the photostability of ZnO NRA/C-x nanohybrids is significantly increased in comparison with the bare ZnO NRA.展开更多
Lithium-sulfur(Li-S)batteries have been regarded as promising energy-storage systems,due to their high theoretical capacity and energy density.However,the carbonaceous sulfur hosts suffer from weak binding force betwe...Lithium-sulfur(Li-S)batteries have been regarded as promising energy-storage systems,due to their high theoretical capacity and energy density.However,the carbonaceous sulfur hosts suffer from weak binding force between the hosts and polysulfides,restricting the cyclic stability of sulfur electrode.Meantime,the presence of binder and conductive agent in the traditional electrode reduces its energy density.This study demonstrates that titanium nitride(TiN)nanorod array on carbon cloth(CC)is employed as a flexible host for highly stable Li-S batteries via solvothermal synthesis-nitridation strategy.On the one hand,the flexible integrated network composed of three-dimensional TiN nanorod array and CC significantly improves the conductivity,increases the electron transport and electrolyte penetration of cathode.On the other hand,the 3D structure of TiN/CC and the enhanced polarity of TiN effectively strengthen the physical and chemical double adsorption for polysulfides.As a result,the combination of TiN nanorod array and CC synergistic ally promotes sulfur utilization and electrochemical performances of S@TiN/CC cathode.A discharge capacity of1015.2 mAh·g^(-1)at 0.5C after 250 cycles and 604.1mAh·g^(-1)at 3C after 250 cycles is realized.Under a larger current density of 5C,the resulting S@TiN/CC cathode maintains a high discharge capacity of 666.6 mAh·g^(-1)and the Coulombic efficiency of about 100%.展开更多
One-dimensional structure of ZnO nanorod arrays on nanocrystalline TiO2/ITO conductive glass substrates has been fabricated by cathodic reduction electrochemical deposition methods in the three-electrode system,with z...One-dimensional structure of ZnO nanorod arrays on nanocrystalline TiO2/ITO conductive glass substrates has been fabricated by cathodic reduction electrochemical deposition methods in the three-electrode system,with zinc nitrate aqueous solution as the electrolyte,and were characterized by X-ray diffraction (XRD),scanning electron microscopy (SEM),energy-dispersive X-ray (EDX) and photoluminescence (PL) spectra.The effects of film substrates,electrolyte concentration,deposition time,and methenamine (HMT) addition on ZnO deposition and its luminescent property were investigated in detail.The results show that,compared with on the ITO glass substrate,ZnO is much easily achieved by electrochemical deposition on the TiO2 nanoparticle thin films.ZnO is hexagonally structured wurtzite with the c-axis preferred growth,and further forms nanorod arrays vertically on the substrates.It is favorable to the growth of ZnO to extend the deposition time,to increase the electrolyte concentration,and to add a certain amount of HMT in the system,consequently improving the crystallinity and orientation of ZnO arrays.It is demonstrated that the obtained ZnO arrays with high crystallinity and good orientation display strong band-edge UV (375 nm) and weak surface-state-related green (520 nm) emission peaks.展开更多
Wettability manipulation of glancing angle deposited Fe/Co/Ni nanorod arrays was realized by X-ray irradiation in ultra-high vacuum chamber. Reversible transition was also purchased by alternating ethanol immersion an...Wettability manipulation of glancing angle deposited Fe/Co/Ni nanorod arrays was realized by X-ray irradiation in ultra-high vacuum chamber. Reversible transition was also purchased by alternating ethanol immersion and X-ray irradiation. Alkyl group adsorption-desorption mechanism and corresponding morphology depen- dence of wettability manipulation were revealed.展开更多
基金National Key R&D Program of China(2016YFB0400800)National Natural Science Foundation of China(61875187,61527814,61674147,U1505253)+1 种基金Beijing Nova Program(Z181100006218007)Youth Innovation Promotion Association of the Chinese Academy of Sciences(2017157)
文摘The nanorod structure is an alternative scheme to develop high-efficiency deep ultraviolet light-emitting diodes(DUV LEDs). In this paper, we first report the electrically injected 274-nm AlGaN nanorod array DUV LEDs fabricated by the nanosphere lithography and dry-etching technique. Nanorod DUV LED devices with good electrical properties are successfully realized. Compared to planar DUV LEDs, nanorod DUV LEDs present>2.5 times improvement in light output power and external quantum efficiency. The internal quantum efficiency of nanorod LEDs increases by 1.2 times due to the transformation of carriers from the exciton to the free electron–hole, possibly driven by the interface state effect of the nanorod sidewall surface. In addition, the nanorod array significantly facilitates photons escaping from the interior of LEDs along the vertical direction, contributing to improved light extraction efficiency. A three-dimensional finite-different time-domain simulation is performed to analyze further in detail the TE-and TM-polarized photon extraction mechanisms of the nanostructure. Our results demonstrate the nanorod structure is a good candidate for high-efficiency DUV emitters.
基金The authors extend their appreciation to the Deanship of Scientific Research at King Khalid University for funding support through large group Research Project(No.RGP2/257/44).
文摘The development of highly efficient and durable oxygen evolution reaction(OER)catalysts for seawater electrolysis is of great importance for applications.Here,an amorphous FeMoO_(4) nanorod array on Ni foam is reported as a highly active OER electrocatalyst in alkaline seawater,requiring only overpotentials of 303 and 332 mV to achieve 100 and 300 mA·cm^(-2),respectively.Moreover,it shows strong long-term electrochemical durability for at least 50 h.
文摘Low optical absorption and photocorrosion are two crucial issues limiting the practical applications of zinc oxide(ZnO)-based photocatalysts.In this paper,we report the fabrication of graphitic-carbon-mediated ZnO nanorod arrays(NRAs)with enhanced photocatalytic activity and photostability for CO2 reduction under visible light irradiation.ZnO NRA/C-x(x=005,01,02,and 03)nanohybrids are prepared by calcining pre-synthesized ZnO NRAs with different amounts of glucose(0.05,0.1,0.2,and 0.3 g)as a carbon source via a hydrothermal method.X-ray photoelectron spectroscopy reveals that the obtained ZnO NRA/C-x nanohybrids are imparted with the effects of both carbon doping and carbon coating,as evidenced by the detected C-O-Zn bond and the C-C,C-O and C=O bonds,respectively.While the basic structure of ZnO remains unchanged,the UV-Vis absorption spectra show increased absorbance owing to the carbon doping effect in the ZnO NRA/C-x nanohybrids.The photoluminescence(PL)intensities of ZnO NRA/C-x nanohybrids are lower than that of bare ZnO NRA,indicating that the graphitic carbon layer coated on the surface of the ZnO NRA significantly enhances the charge carrier separation and transport,which in turn enhances the photoelectrochemical property and photocatalytic activity of the ZnO NRA/C-x nanohybrids for CO2 reduction.More importantly,a long-term reaction of photocatalytic CO2 reduction demonstrates that the photostability of ZnO NRA/C-x nanohybrids is significantly increased in comparison with the bare ZnO NRA.
基金financially supported by the National Natural Science Foundation of China (Nos.22179064,91963119,21805140,51772157,21905141,22203046 and62174087)China Postdoctoral Science Foundation (No.2018M642287)+2 种基金Jiangsu Province Postdoctoral Research Grant Program (No.2018K156C)Jiangsu National Synergetic Innovation Center for Advanced Materials (SICAM)the Synergetic Innovation Center for Organic Electronics and Information Displays。
文摘Lithium-sulfur(Li-S)batteries have been regarded as promising energy-storage systems,due to their high theoretical capacity and energy density.However,the carbonaceous sulfur hosts suffer from weak binding force between the hosts and polysulfides,restricting the cyclic stability of sulfur electrode.Meantime,the presence of binder and conductive agent in the traditional electrode reduces its energy density.This study demonstrates that titanium nitride(TiN)nanorod array on carbon cloth(CC)is employed as a flexible host for highly stable Li-S batteries via solvothermal synthesis-nitridation strategy.On the one hand,the flexible integrated network composed of three-dimensional TiN nanorod array and CC significantly improves the conductivity,increases the electron transport and electrolyte penetration of cathode.On the other hand,the 3D structure of TiN/CC and the enhanced polarity of TiN effectively strengthen the physical and chemical double adsorption for polysulfides.As a result,the combination of TiN nanorod array and CC synergistic ally promotes sulfur utilization and electrochemical performances of S@TiN/CC cathode.A discharge capacity of1015.2 mAh·g^(-1)at 0.5C after 250 cycles and 604.1mAh·g^(-1)at 3C after 250 cycles is realized.Under a larger current density of 5C,the resulting S@TiN/CC cathode maintains a high discharge capacity of 666.6 mAh·g^(-1)and the Coulombic efficiency of about 100%.
基金supported by the program for New Century Excellent Talents in Universities (NCET-07-259)the Key Project of Science & Technology Research of the Ministry of Education of China (207027)the Science Foundation of Excellent Youth of Heilongjiang Province of China (JC200701)
文摘One-dimensional structure of ZnO nanorod arrays on nanocrystalline TiO2/ITO conductive glass substrates has been fabricated by cathodic reduction electrochemical deposition methods in the three-electrode system,with zinc nitrate aqueous solution as the electrolyte,and were characterized by X-ray diffraction (XRD),scanning electron microscopy (SEM),energy-dispersive X-ray (EDX) and photoluminescence (PL) spectra.The effects of film substrates,electrolyte concentration,deposition time,and methenamine (HMT) addition on ZnO deposition and its luminescent property were investigated in detail.The results show that,compared with on the ITO glass substrate,ZnO is much easily achieved by electrochemical deposition on the TiO2 nanoparticle thin films.ZnO is hexagonally structured wurtzite with the c-axis preferred growth,and further forms nanorod arrays vertically on the substrates.It is favorable to the growth of ZnO to extend the deposition time,to increase the electrolyte concentration,and to add a certain amount of HMT in the system,consequently improving the crystallinity and orientation of ZnO arrays.It is demonstrated that the obtained ZnO arrays with high crystallinity and good orientation display strong band-edge UV (375 nm) and weak surface-state-related green (520 nm) emission peaks.
文摘Wettability manipulation of glancing angle deposited Fe/Co/Ni nanorod arrays was realized by X-ray irradiation in ultra-high vacuum chamber. Reversible transition was also purchased by alternating ethanol immersion and X-ray irradiation. Alkyl group adsorption-desorption mechanism and corresponding morphology depen- dence of wettability manipulation were revealed.
