Three methods including the atomic resolved density of state, charge difference density, and the transition density matrix are used to visualize metal to ligand charge transfer （MLCT） in ruthenium（II） ammine compl...Three methods including the atomic resolved density of state, charge difference density, and the transition density matrix are used to visualize metal to ligand charge transfer （MLCT） in ruthenium（II） ammine complex. The atomic resolved density of state shows that there is density of Ru on the HOMOs. All the density is localized on the ammine, which reveals that the excited electrons in the Ru complex are delocalized over the ammine ligand. The charge difference density shows that all the holes are localized on the Ru and the electrons on the ammine. The localization explains the MLCT on excitation. The transition density matrix shows that there is electron-hole coherence between Ru and ammine. These methods are also used to examine the MLCT in Os（bpy）2（p0p）Cl （＂Osp0p＂： bpy=2,2-bipyrldyl; p0p=4,4＇- bipyridyl） and the ligand-to-ligand charge transfer （LLCT） in Alq3. The calculated results show that these methods are powerful to examine MLCT and LLCT in the metal-ligand system.展开更多
The purpose of this work relates to study on the characteristics of ultra thin gate oxide (2 5nm thickness) and the effect of metal Al,Zr,and Ta contamination on GOI.The controlled metallic contamination experiments...The purpose of this work relates to study on the characteristics of ultra thin gate oxide (2 5nm thickness) and the effect of metal Al,Zr,and Ta contamination on GOI.The controlled metallic contamination experiments are carried out by depositing a few ppm contaminated metal and low pH solutions on the wafers.The maximum metal surface concentration is controlled at about 10 12 cm -2 level in order to simulate metal contamination during ultra clean processing.A ramped current stress for intrinsic charge to breakdown measurements with gate injection mode is used to examine the characteristics of these ultra thin gate oxides and the effect of metal contamination on GOI.It is the first time to investigate the influence of metal Zr and Ta contamination on 2 5nm ultra thin gate oxide.It is demonstrated that there is little effect of Al contamination on GOI,while Zr contamination is the most detrimental to GOI,and early breakdown has happened to wafers contaminated by Ta.展开更多
To elucidate the nature of low-lying triplet states and the effect of ligand modifica- tions on the excited-state properties of functional cationic iridium complexes, the solvent- dependent excited-state dynamics of t...To elucidate the nature of low-lying triplet states and the effect of ligand modifica- tions on the excited-state properties of functional cationic iridium complexes, the solvent- dependent excited-state dynamics of two phosphorescent cationic iridium（Ⅲ） complexes, namely [Ir（dph-oxd）2（bpy）]PF6 （1） and [Ir（dph-oxd）2（pzpy）]Pf6 （2）, were investigated by femtosecond and nanosecond transient absorption spectroscopy. Upon photoexcitation to the metal-to-ligand charge-transfer （MLCT） states, the excited-state dynamics shows a rapid process （τ-=0.7-3 ps） for the formation of solvent stabilized 3MLCT states, which significantly depends on the solvent polarity for both 1 and 2. Sequentially, a relatively slow process assigned to the vibrational cooling/geometrical relaxation and a long-lived phospho- rescent emissive state is identified. Due to the different excited-state electronic structures regulated by ancillary ligands, the solvation-induced stabilization of the 3MLCT state in 1 is faster than that in 2. The present results provide a better sight of excited-state relaxation dynamics of ligand-related iridium（Ⅲ） complexes and solvation effects on triplet manifolds.展开更多
A novel 3 D bismuth-organic framework(called Bi-TBAPy) single crystal was synthesized by employing 1,3,6,8-tetrakis(p-benzoic acid)pyrene(H4TBAPy) as an organic linker. The study demonstrates that the Bi-TBAPy not onl...A novel 3 D bismuth-organic framework(called Bi-TBAPy) single crystal was synthesized by employing 1,3,6,8-tetrakis(p-benzoic acid)pyrene(H4TBAPy) as an organic linker. The study demonstrates that the Bi-TBAPy not only possesses good chemical stability and suitable band edge positions for promising photocatalytic H2 evolution, but it also exhibits a typical ligand-to-metal charge transfer for favorable charge separation. The photocatalytic H2 evolution rates on the as-obtained Bi-TBAPy with different cocatalysts modified were examined with triethanolamine as the sacrificial reagent. Based on this, the hydrogen evolution rate of 140 μmol h-1 g-1 was obtained on the optimized sample with a loading of 2 wt% Pt as a cocatalyst. To the best of our knowledge, this is the first bismuth-based metal-organic framework(MOF) that functions as an effective photocatalyst for photocatalytic water reduction. Our study not only adds a new member to the family of photocatalyst materials, but also reveals the importance of cocatalyst modification in improving photocatalytic activity of MOFs.展开更多
A detailed understanding of the composition,buffering capacity,surface charge property,and metals leaching behavior of bauxite residue is the key to improved management,both in reducing the environmental impact and us...A detailed understanding of the composition,buffering capacity,surface charge property,and metals leaching behavior of bauxite residue is the key to improved management,both in reducing the environmental impact and using the material as an industrial by-product for other applications.In this study,physical,chemical,and surface charge properties of bauxite residue derived from a combined process were investigated.Results indicated that the main alkaline solids in bauxite residue were katoite,sodalite,and calcite.These minerals also lead to a higher acid neutralizing capacity of bauxite residue.Acid neutralizing capacity(ANC)to pH 7.0 of this residue is about 0.9 mol H^+/kg solid.Meanwhile,the Fe-,Al-,and Si-containing minerals in bauxite residue resulted in an active surface;The isoelectric point(IEP)and point of zero charge(PZC)were 7.88 and 7.65,respectively.This also leads to a fact that most of the metals in bauxite residue were adsorbed by these surface charged solids,which makes the metals not readily move under natural or even moderately acidic conditions.The leaching behavior of metals as a function of pH indicated that the metals in bauxite residue present low release concentrations(pH>3).展开更多
Charge carriers in organic semiconductor are different from that of traditional inorganic semiconductor. Based on three-current model, considering electrical field effect, we present a theoretical model to discuss spi...Charge carriers in organic semiconductor are different from that of traditional inorganic semiconductor. Based on three-current model, considering electrical field effect, we present a theoretical model to discuss spin-polarized injection from ferromagnetic electrode into organic semiconductor by analyzing electrochemical potential both in ferromagnetic electrode and organic semiconductors. The calculated result of this model shows effects of electrode＇s spin polarization, equilibrium value of polarons ratio, interracial conductance, bulk conductivity of materials and electrical field. It is found that we could get decent spin polarization with common ferromagnetic electrode by increasing equilibrium value of polarons ratio. We also find that large and matched bulk conductivity of organic semiconductor and electrode, small spin-dependent interracial conductance, and enough large electrical field are critical factors for increasing spin polarization.展开更多
Photocatalytic hydrogen production based on semiconductor photocatalysts has been considered as one of the most promising strategies to resolve the global energy shortage.Graphitic carbon nitride(g‐C3N4)has been a st...Photocatalytic hydrogen production based on semiconductor photocatalysts has been considered as one of the most promising strategies to resolve the global energy shortage.Graphitic carbon nitride(g‐C3N4)has been a star visible‐light photocatalyst in this field due to its various advantages.However,pristine g‐C3N4usually exhibits limited activity.Herein,to enhance the performance of g‐C3N4,alkali metal ion(Li+,Na+,or K+)‐doped g‐C3N4are prepared via facile high‐temperature treatment.The prepared samples are characterized and analyzed using the technique of XRD,ICP‐AES,SEM,UV‐vis DRS,BET,XPS,PL,TRPL,photoelectrochemical measurements,photocatalytic tests,etc.The resultant doped photocatalysts show enhanced visible‐light photocatalytic activities for hydrogen production,benefiting from the increased specific surface areas(which provide more active sites),decreased band gaps for extended visible‐light absorption,and improved electronic structures for efficient charge transfer.In particular,because of the optimal tuning of both microstructure and electronic structure,the Na‐doped g‐C3N4shows the most effective utilization of photogenerated electrons during the water reduction process.As a result,the highest photocatalytic performance is achieved over the Na‐doped g‐C3N4photocatalyst(18.7?mol/h),3.7times that of pristine g‐C3N4(5.0?mol/h).This work gives a systematic study for the understanding of doping effect of alkali metals in semiconductor photocatalysis.展开更多
The principle of the two carriers contributing to carry the pixel signal charges is firstly presented,and then the bipolar junction photogate transistor(BJPT)with high performance is proposed for the CMOS image sensor...The principle of the two carriers contributing to carry the pixel signal charges is firstly presented,and then the bipolar junction photogate transistor(BJPT)with high performance is proposed for the CMOS image sensor.The numerical analytical model of the photo-charge transfer for the bipolar junction photogate is established in detail. Some numerical simulations are obtained under 0.6 μm CMOS process,which show that its readout rate increases exponentially with the increase of the photo-charge at applied voltage.展开更多
基金supported by the National Natural Science Foundation of China(51603185,51673174)Zhejiang Provincial Natural Science Foundation of China(LQ19E030016,LY19E030006,LZ17E030001)+1 种基金China Postdoctoral Science Foundation(2018M632498)the Zhejiang Provincial Postdoctoral fellowship,China(Z71101009)~~
基金This work was supported by National Natural Science Foundation of China （No.10505001, No.10875055, and No.10874234） and the Educational Department of Liaoning Province （No.2008228）.
文摘Three methods including the atomic resolved density of state, charge difference density, and the transition density matrix are used to visualize metal to ligand charge transfer （MLCT） in ruthenium（II） ammine complex. The atomic resolved density of state shows that there is density of Ru on the HOMOs. All the density is localized on the ammine, which reveals that the excited electrons in the Ru complex are delocalized over the ammine ligand. The charge difference density shows that all the holes are localized on the Ru and the electrons on the ammine. The localization explains the MLCT on excitation. The transition density matrix shows that there is electron-hole coherence between Ru and ammine. These methods are also used to examine the MLCT in Os（bpy）2（p0p）Cl （＂Osp0p＂： bpy=2,2-bipyrldyl; p0p=4,4＇- bipyridyl） and the ligand-to-ligand charge transfer （LLCT） in Alq3. The calculated results show that these methods are powerful to examine MLCT and LLCT in the metal-ligand system.
文摘The purpose of this work relates to study on the characteristics of ultra thin gate oxide (2 5nm thickness) and the effect of metal Al,Zr,and Ta contamination on GOI.The controlled metallic contamination experiments are carried out by depositing a few ppm contaminated metal and low pH solutions on the wafers.The maximum metal surface concentration is controlled at about 10 12 cm -2 level in order to simulate metal contamination during ultra clean processing.A ramped current stress for intrinsic charge to breakdown measurements with gate injection mode is used to examine the characteristics of these ultra thin gate oxides and the effect of metal contamination on GOI.It is the first time to investigate the influence of metal Zr and Ta contamination on 2 5nm ultra thin gate oxide.It is demonstrated that there is little effect of Al contamination on GOI,while Zr contamination is the most detrimental to GOI,and early breakdown has happened to wafers contaminated by Ta.
文摘To elucidate the nature of low-lying triplet states and the effect of ligand modifica- tions on the excited-state properties of functional cationic iridium complexes, the solvent- dependent excited-state dynamics of two phosphorescent cationic iridium（Ⅲ） complexes, namely [Ir（dph-oxd）2（bpy）]PF6 （1） and [Ir（dph-oxd）2（pzpy）]Pf6 （2）, were investigated by femtosecond and nanosecond transient absorption spectroscopy. Upon photoexcitation to the metal-to-ligand charge-transfer （MLCT） states, the excited-state dynamics shows a rapid process （τ-=0.7-3 ps） for the formation of solvent stabilized 3MLCT states, which significantly depends on the solvent polarity for both 1 and 2. Sequentially, a relatively slow process assigned to the vibrational cooling/geometrical relaxation and a long-lived phospho- rescent emissive state is identified. Due to the different excited-state electronic structures regulated by ancillary ligands, the solvation-induced stabilization of the 3MLCT state in 1 is faster than that in 2. The present results provide a better sight of excited-state relaxation dynamics of ligand-related iridium（Ⅲ） complexes and solvation effects on triplet manifolds.
基金supported by the National Natural Science Foundation of China(21633009,21522306,21633010)DICP&QIBEBT(UN201805)the Dalian Science Foundation for Distinguished Young Scholars(2017RJ02)~~
文摘A novel 3 D bismuth-organic framework(called Bi-TBAPy) single crystal was synthesized by employing 1,3,6,8-tetrakis(p-benzoic acid)pyrene(H4TBAPy) as an organic linker. The study demonstrates that the Bi-TBAPy not only possesses good chemical stability and suitable band edge positions for promising photocatalytic H2 evolution, but it also exhibits a typical ligand-to-metal charge transfer for favorable charge separation. The photocatalytic H2 evolution rates on the as-obtained Bi-TBAPy with different cocatalysts modified were examined with triethanolamine as the sacrificial reagent. Based on this, the hydrogen evolution rate of 140 μmol h-1 g-1 was obtained on the optimized sample with a loading of 2 wt% Pt as a cocatalyst. To the best of our knowledge, this is the first bismuth-based metal-organic framework(MOF) that functions as an effective photocatalyst for photocatalytic water reduction. Our study not only adds a new member to the family of photocatalyst materials, but also reveals the importance of cocatalyst modification in improving photocatalytic activity of MOFs.
基金Projects(41501350,41461071,31860170)supported by the National Natural Science Foundation of China
文摘A detailed understanding of the composition,buffering capacity,surface charge property,and metals leaching behavior of bauxite residue is the key to improved management,both in reducing the environmental impact and using the material as an industrial by-product for other applications.In this study,physical,chemical,and surface charge properties of bauxite residue derived from a combined process were investigated.Results indicated that the main alkaline solids in bauxite residue were katoite,sodalite,and calcite.These minerals also lead to a higher acid neutralizing capacity of bauxite residue.Acid neutralizing capacity(ANC)to pH 7.0 of this residue is about 0.9 mol H^+/kg solid.Meanwhile,the Fe-,Al-,and Si-containing minerals in bauxite residue resulted in an active surface;The isoelectric point(IEP)and point of zero charge(PZC)were 7.88 and 7.65,respectively.This also leads to a fact that most of the metals in bauxite residue were adsorbed by these surface charged solids,which makes the metals not readily move under natural or even moderately acidic conditions.The leaching behavior of metals as a function of pH indicated that the metals in bauxite residue present low release concentrations(pH>3).
基金Supported by the Natural Science Foundation of Shandong Province under Grant No.Y2006A18 the Key Programme of Nature Foundation of Shandong Jianzhu University under Grant No.XZ050102
文摘Charge carriers in organic semiconductor are different from that of traditional inorganic semiconductor. Based on three-current model, considering electrical field effect, we present a theoretical model to discuss spin-polarized injection from ferromagnetic electrode into organic semiconductor by analyzing electrochemical potential both in ferromagnetic electrode and organic semiconductors. The calculated result of this model shows effects of electrode＇s spin polarization, equilibrium value of polarons ratio, interracial conductance, bulk conductivity of materials and electrical field. It is found that we could get decent spin polarization with common ferromagnetic electrode by increasing equilibrium value of polarons ratio. We also find that large and matched bulk conductivity of organic semiconductor and electrode, small spin-dependent interracial conductance, and enough large electrical field are critical factors for increasing spin polarization.
基金supported by the National Natural Science Foundation of of China(51472191,21407115,21773179)the Natural Science Foundation of Hubei Province of China(2017CFA031)the Opening Project of Key Laboratory of Optoelectronic Chemical Materials and Devices,Ministry of Education(JDGD-201509)~~
文摘Photocatalytic hydrogen production based on semiconductor photocatalysts has been considered as one of the most promising strategies to resolve the global energy shortage.Graphitic carbon nitride(g‐C3N4)has been a star visible‐light photocatalyst in this field due to its various advantages.However,pristine g‐C3N4usually exhibits limited activity.Herein,to enhance the performance of g‐C3N4,alkali metal ion(Li+,Na+,or K+)‐doped g‐C3N4are prepared via facile high‐temperature treatment.The prepared samples are characterized and analyzed using the technique of XRD,ICP‐AES,SEM,UV‐vis DRS,BET,XPS,PL,TRPL,photoelectrochemical measurements,photocatalytic tests,etc.The resultant doped photocatalysts show enhanced visible‐light photocatalytic activities for hydrogen production,benefiting from the increased specific surface areas(which provide more active sites),decreased band gaps for extended visible‐light absorption,and improved electronic structures for efficient charge transfer.In particular,because of the optimal tuning of both microstructure and electronic structure,the Na‐doped g‐C3N4shows the most effective utilization of photogenerated electrons during the water reduction process.As a result,the highest photocatalytic performance is achieved over the Na‐doped g‐C3N4photocatalyst(18.7?mol/h),3.7times that of pristine g‐C3N4(5.0?mol/h).This work gives a systematic study for the understanding of doping effect of alkali metals in semiconductor photocatalysis.
文摘The principle of the two carriers contributing to carry the pixel signal charges is firstly presented,and then the bipolar junction photogate transistor(BJPT)with high performance is proposed for the CMOS image sensor.The numerical analytical model of the photo-charge transfer for the bipolar junction photogate is established in detail. Some numerical simulations are obtained under 0.6 μm CMOS process,which show that its readout rate increases exponentially with the increase of the photo-charge at applied voltage.
