n—GaAs（100）,Si（111）表面修饰卟啉分子的光致界面电荷转移…

利用表面光电压谱研究了四碘化四－（４－三甲胺苯基）卟啉（ＴＴＭＡＰＰＩＨ２）修饰ｎ－ＧａＡＳ（１００）和ｎ－Ｓｉ（１１１）半导体表面的光致界面电荷转移特性。结果表明，ｎ－ＧａＡｓ（１００）表面修饰ＴＴＭＡＰＰＩＨ２分子的光致界面电荷转移效率远比ｎ－Ｓｉ（１１１）表面修饰的高，并且发现在该卟啉分子的非吸收区也有明显的光致界面电荷转移现象，而与ｎ－Ｓｉ（１１１）间则没有这种转移特性。用电化学测量和ＵＶ     

CuTSPc分子膜/p-Si(111)界面的光致电荷转移及其机制研究

本文利用L-B技术,在p-Si(111)基底上铺展了单层厚度只有6Å的CuTSPc超薄分子膜(简称超分子膜)和具有C₁₈脂链间隙的CuTSPc L-B膜两种膜系,首次观察到了CuTSPc分子膜在这种特定界面中的表面光电压谱。并且发现,当CuTSPc仅为一个单分子层时,这两种膜系的表面光伏效应最强。我们的研究结果表明,只有紧邻半导体基底的一个单分子层厚度的染料分子对光致界面电荷转移起关键作用。最后在实验上证实这种电荷转移是电荷直接注入机制,而非间接注入机制。     

四苯基卟啉质子化结构变化的理论研究(Ⅱ)——五氟苯基及吡咯环上氟的取代基效应

卟啉的衍生物在DNA螺旋中的嵌入并堆积具有高选择性.为考察5,10,15,20-四(五氟苯基)卟啉(TF₅-PPH₂)和2,3,7,8,12,13,17,18-八氟-5,10,15,20-四(五氟苯基)卟啉(F₂₈TPPH₂)中F取代基对质子化卟啉结构的影响,在四苯基卟啉研究的基础上,用半经验的AM₁MO方法,并进行合理的对称性限制,计算了TF₅-PPH₂和F₂₈TPPH₂及其质子化二酸(TF₅-PPH₄²⁺)和(F₂₈TPPH₄²⁺)的几种可能的构型.结果表明,由于F取代基的影响,质子化过程中的结构、键电荷布居和前线分子轨道均有明显的变化,二者的质子化二酸与溶液质子的快速交换作用也都变得更加困难.     

四(对-甲酰基二茂铁-3-乙氧基)苯基卟啉的合成及电化学性质

设计合成了一种由卟啉与二茂铁通过共价键连接的四(对-甲酰基二茂铁-3-乙氧基)苯基卟啉化合物(Fe-PH₂), 采用红外光谱、核磁共振氢谱和紫外光谱等手段对其结构进行了表征, 证实所合成的为目标产物. 紫外光谱和荧光光谱结果表明, 该卟啉体系内部给受体之间在基态下存在弱的相互作用, 而在激发态下存在较强的相互作用. 电化学测试结果表明, 连接4个二茂铁基的Fe-PH₂具有更丰富的氧化还原性质.     

meso-5,10,15,20-四[4-(N-吡咯烷基)苯基]卟啉的合成及对牛血清白蛋白的作用

基于卟啉对癌细胞的特殊亲和作用和吡咯烷化合物的抗肿瘤及抗癌活性,设计并合成了具有吡咯烷结构的新型卟啉化合物--meso-5,10,15,20-四[4-(N-吡咯烷基)苯基]卟啉(TBPPH₂),利用荧光光度法和紫外-可见分光光度法研究了TBPPH₂与牛血清白蛋白(BSA)的相互作用.实验发现,TBPPH₂利用疏水作用力进入BSA的疏水性腔,与BSA形成配合物并引起BSA的静态荧光猝灭.在TBPPH₂与BSA的相互作用过程中,TBPPH₂与BSA以摩尔比1∶1牢固结合,TBPPH₂与BSA分子中色氨酸间的最近距离r=2.4nm.反应平衡常数K_A=2.51×10⁴L/mol,反应熵变ΔS=84.18J/(mol·K),TBPPH₂与BSA的结合常数K_B=5.13×10⁵L/mol.研究结果表明,吡咯烷基卟啉可能成为一类新型的抗肿瘤及抗病毒药物.     

异质结界面修饰对TiO2/P3HT杂化太阳电池光电性能的增强作用

采用水热法在F-SnO₂(FTO)导电玻璃上制备了一维TiO₂纳米棒阵列, 将一种两亲有机三苯胺染料M分子吸附在其表面, 进而旋涂有机聚合物聚3-己基噻吩P3HT, 构建结构为FTO/TiO₂/M/P3HT/PEDOT:PSS/Au的杂化太阳电池. 瞬态光电流谱反映在杂化电极中存在pn异质结. 接触角测试表明TiO₂表面吸附有机M分子后, 亲水性表面转变为疏水性表面, 利于与聚合物P3HT的进一步接触; 稳态荧光发射光谱表明经修饰的杂化电极的荧光发射强度降低, 由荧光衰减曲线拟合得到的荧光寿命降低, 说明在TiO₂与P3HT之间存在有效的电荷转移, 电荷复合被抑制. 电化学阻抗分析表明界面修饰后电子复合电阻和电子寿命增大. 电池的特性参数均比界面修饰前有所提高, 光电转换效率为1.61%. 另外, 对该电池的工作机理、电荷传输过程进行了初步探讨.     

联氨在d-过渡金属配合物MTP(o-NO2)TBP修饰石墨电极上的催化氧化研究

研究了N₂H₄在间-四(邻-硝基苯基)四苯并卟啉铁(Ⅲ)、钴(Ⅱ)、锌(Ⅱ)和镍(Ⅱ)配合物[MTP(o-NO₂)TBP,简称MTBP]修饰石墨电极上的催化电氧化反应,测得该系列金属四苯并卟啉的催化活性的顺序为Co(Ⅱ)TBP>ClFe(Ⅲ)TBP>Ni(Ⅱ)TBP>Zn(Ⅱ)TBP≈石墨,考察了Co(Ⅱ)TBP和ClFe(Ⅲ)TBP催化联氨电氧化反应的动力学过程.结果表明,OH^-和N₂H₄在ClFe(Ⅱ)TBP修饰电极上的反应级数分别为2和1,而在Co(Ⅱ)TBP修饰电极上的均为1.根据电化学参数提出了可能的反应机理.     

低对称性硫代烃基四氮杂卟啉的合成、表征及电化学性质研究

合成了硫代烃基四氮杂卟啉2,3,7,8,12,13-六(甲硫基)-17,18-一(二噻英)四氮杂卟啉[H₂Pz(dtn)(mt)₆]及其过渡金属配合物MPz(dtn)(mt)₆,由元素分析、质谱、¹HNMR、UV-Vis和IR光谱对其组成和结构进行了表征,通过循环伏安测试结果讨论了H₂Pz(dtn)(mt)₆的电化学性质,证明H₂Pz(dtn)(mt)₆的还原过程为单电子连续传输过程,属于CE机理.研究了H₂Pz(dtn)(mt)₆对正极材料MnO₂在锂离子电池中的修饰作用.结果表明,H₂Pz(dtn)(mt)₆对改善锂离子电池的初始充放电容量和循环次数都有明显的增加.     

过渡金属吡啶配离子的TCNQ电荷转移盐的合成和物理性质

合成了通式为[M(Py)_m][TCNQ]_n(M=Mn,m＝4;M＝Co,Ni,Cu,m＝2;TCNQ＝7,7,8,8-四氰基对苯醌二甲烷,n＝2,3)的8个过渡金属吡啶配离子的TCNQ电荷转移盐,通过元素分析、红外光谱、顺磁共振谱、光电子能谱、磁化率和电导率对这些电荷转移盐进行了表征,结果表明,在这些电荷转移盐分子中存在TCNQ^-和TCNQ⁰,且TCNQ^-与TCNQ⁰相互作用形成结构单元[TCNQ]_n^2-(n＝2,3),各个结构单元沿一维方向堆积形成分子柱,部分电荷从[TCNQ]_n^2-向[M(Py)_m]²⁺转移,导致化合物中的金属表现为混合价态.其中3个电荷转移盐具有良好的导电性.     

四芳基卟啉锰配离子的TCNQ电荷转移盐的合成和物理性质

合成了13个四芳基卟啉锰配离子的TCNQ电荷转移盐[TAPMn][TCNQ]_n(TAPH₂=α,β,γ,δ-四芳基卟啉;A=C₆H₅,4-CH₃C₆H₄,4-CH₃OC₆H₄,4-ClC₆H₄,3-ClC₆H₄,3-FC₆H₄,4-(CH₃)₂NC₆H₄,2,4-Cl₂C₆H₃;TCNQ=7,7,8,8-四氰基对苯醌二甲烷;n=1,2).通过元素分析、IR、XPS、ESR、磁化率和电导率对其进行了表征.结果表明:这些电荷转移盐分子中存在TCNQ⁰和TCNQ^-,且TCNQ⁰和TCNQ^-之间存在相互作用,部分电荷从[TCNQ]_n^-向[TAPMn]⁺转移,导致化合物中的锰表现为混合价态.复合盐的室温电导率在10^-7～10^-10S·cm^-1,属于有机半导体,简单盐的室温电导率小于10^-11S·cm^-1.     

Light-Induced Charge Transfer at Interface Between Lipid-Free RhTSPc Film and p-Si(111)

The present paper covers the lipid-free rhodium tetrasulfonato-phthalocyanine (RhTSPc) films prepared on p-Si(111) by using Langmuir-Blodgett technique. Their surface photovoltage spectra were measured. It was found that there is a strong interaction at the interface between the RhTSPc film and p-Si (111) and that the surface photovoltaic effect of the film system is maximum when only one monolayer of RhTSPc molecules coats p-Si(111), which is similar to that of CuTSPc films on p-Si(111) reported previously. These results confirm that only the monolayer of dye molecules being adjacent to the semiconductor surface plays a key role in the light-induced interfacial charge transfer process.     

聚马来酸偶氮萘己单酯LB膜对n—Si（100）的光敏化作用

合成了聚马来酸{6-[4-(1-偶氮)-萘氧]己基}单酯功能化合物,并在不同基底(CaF_2,n-Si(100))上沉积其LB膜,利用UV-Vis和IR光谱对膜性质和结构进行了表征.对膜修饰表面的硅片表面光电压谱测试发现,它对单晶硅具有很强的敏化作用.对界面电子过程也进行了初步讨论.     

Surface state engineering of molecule-molecule interactions

Engineering the electronic structure of organics through interface manipulation, particularly the interface dipole and the barriers to charge carrier injection, is of essential importance to improve organic devices. This requires the meticulous fabrication of desired organic structures by precisely controlling the interactions between molecules. The well-known principles of organic coordination chemistry cannot be applied without proper consideration of extra molecular hybridization, charge transfer and dipole formation at the interfaces. Here we identify the interplay between energy level alignment, charge transfer, surface dipole and charge pillow effect and show how these effects collectively determine the net force between adsorbed porphyrin 2H-TPP on Cu(111). We show that the forces between supported porphyrins can be altered by controlling the amount of charge transferred across the interface accurately through the relative alignment of molecular electronic levels with respect to the Shockley surface state of the metal substrate, and hence govern the self-assembly of the molecules.     

n-Si/TiO2/偶氮颜料微纳米尺度下的光生电荷转移性质

本文利用KFM 研究了n-Si/TiO₂/偶氮类颜料微纳米尺度下的光生电荷转移性质, 为进一步理解光电活性体系工作的微观机理提供了依据.     

Self-organized monolayer of meso-tetradodecylporphyrin coordinated to Au(111)

The structure of molecular monolayers formed at the interface between atomically flat surfaces and a solution of free-base meso-tetradodecylporphyrins (H2Ps) was examined by scanning tunneling microscopy (STM) at the liquid/solid interface. On the surface of graphite (HOPG), H2Ps form a well-ordered monolayer characterized by an oblique unit cell. On Au(111), H2Ps form a self-organized monolayer comprised of two distinct domain types. In both types of domains, the density of the porphyrin cores is increased in comparison to the arrangement observed on HOPG. Also, high-resolution STM images reveal that, in contrast to what is observed on HOPG, physisorption on Au(111) induces a distortion of the porphyrin macrocycle out of planarity. By using X-ray photoelectron spectroscopy, we demonstrate that this is likely to be due to the coordination of the lone pairs of the iminic (-C=N-) nitrogen atoms of the porphyrin macrocycle to Au(111).     

聚苯胺类/n-Si(111)单晶硅复合电极:制备与光电性质

在过氧化月桂酰作用下,于n-Si(111)型单晶硅表面上分别嫁接苯胺及烷基取代苯胺,进而实现晶体硅表面上聚苯胺和烷基取代聚苯胺的原位聚合,制备得到了系列聚苯胺(或烷基取代聚苯胺)/n-Si(111)单晶硅复合电极。此外,对上述合成电极表面苯胺链进行磺化,得到系列磺酸基化的单晶硅复合电极。电化学研究结果显示,聚苯胺直接嫁接于晶体硅表面所得到的复合电极光电转化效率最高,苯胺聚合链通过碳碳双键桥连于单晶硅表面所得到复合电极的光电转化效率高于通过碳碳单键桥连得到的复合电极,但其光电转化效率低于苯胺聚合链直接桥连于晶体硅表面而得到的复合电极。另外发现,苯环磺酸基化有利于提高复合电极的光电转化效率。     

Charge transfer dynamics of 3,4,9,10-perylene-tetracarboxylic-dianhydride molecules on Au(111) probed by resonant photoemission spectroscopy

Charge transfer dynamics across the lying-down 3,4,9,10-perylene-tetracarboxylic-dianhydride (PTCDA) organic semiconductor molecules on Au(111) interface has been investigated using the core-hole clock implementation of resonant photoemission spectroscopy. It is found that the charge transfer time scale at the PTCDA∕Au(111) interface is much larger than the C 1s core-hole lifetime of 6 fs, indicating weak electronic coupling between PTCDA and the gold substrate due to the absence of chemical reaction and∕or bonding.     

聚苯胺类/n-Si(111)单晶硅复合电极:制备与光电性质

在过氧化月桂酰作用下,于n-Si(111)型单晶硅表面上分别嫁接苯胺及烷基取代苯胺,进而实现晶体硅表面上聚苯胺和烷基取代聚苯胺的原位聚合,制备得到了系列聚苯胺(或烷基取代聚苯胺)/n-Si(111)单晶硅复合电极。此外,对上述合成电极表面苯胺链进行磺化,得到系列磺酸基化的单晶硅复合电极。电化学研究结果显示,聚苯胺直接嫁接于晶体硅表面所得到的复合电极光电转化效率最高,苯胺聚合链通过碳碳双键桥连于单晶硅表面所得到复合电极的光电转化效率高于通过碳碳单键桥连得到的复合电极,但其光电转化效率低于苯胺聚合链直接桥连于晶体硅表面而得到的复合电极。另外发现,苯环磺酸基化有利于提高复合电极的光电转化效率。     

Porphyrins for dye-sensitised solar cells: new insights into efficiency-determining electron transfer steps

Porphyrin molecules offer immense potential as the light harvesting component of dye-sensitised nanocrystalline TiO(2) solar cells. Synthetic porphyrin dyes were amongst the first dyes trialled for sensitisation of inorganic semiconducting oxides. Today, they exhibit the best performance reported for dye-sensitised solar cells. Accompanying the significant performance improvement over the last two decades is a much improved understanding of efficiency-determining fundamental electron transfer steps, from charge photogeneration to recombination. In this feature article we highlight our recent discoveries of the influence of porphyrin molecule structure on efficiency determining electron transfer kinetics and device performance by systematically changing the molecular structure and observing electron injection and recombination kinetics using time-resolved optical and electrical probes. Despite our observation of ultrafast charge injection for all porphyrin dyes studied by transient absorption spectroscopy, the injection yield estimated using an internal standard remains below 100% and depends strongly on the molecular structure. The observed discrepancy between kinetic competition and the injection yield is attributed to non-injecting dyes, probably arising due to inhomogeneity. A very interesting sub-ns (0.5 ns to 100 ns) charge recombination channel between photo-injected electrons and porphyrin cations is observed, which is found to be more prominent in free-base porphyrin dyes with a conjugated linker. Charge recombination between the acceptor species in the redox containing electrolyte and injected electrons is shown to be an important limitation of most porphyrin-sensitised solar cells, accelerated by the presence of porphyrin molecules at the TiO(2)-electrolyte interface. This recombination reaction is strongly dependent on the porphyrin molecular structure. Bulky substituents, using a porphyrin dimer instead of a porphyrin monomer, a light soaking treatment of freshly prepared films and co-sensitization of TiO(2) with multiple dyes are shown to be successful strategies to improve electron lifetime. Finally, new developments unique to porphyrin dye-sensitised solar cells, including performance enhancements from a light exposure treatment of a zinc porphyrin dye, a significant performance improvement observed after co-sensitisation of TiO(2) with free-base and zinc porphyrin dyes and the use of porphyrin dimers with increased light harvesting in thin-film TiO(2) solar cells are described.     

长链香豆素LB膜对n-Si/Ni液结上的光致电荷转移的影响

本文研究了由硬脂酸香豆素制得的LB膜对n-Si/Ni电极性能的修饰作用.该LB膜沉积方式是Z型的,成膜之后吸收蓝移(由343nm移至325nm).在60mW·cm^-2溴钨灯光照下,n-Si/Ni/3LB/Fe(CN) /Pt电池的光电转换效率增大了一倍,稳定性亦有明显改善.交流阻抗测量表明,光照使n-Si/Ni/3LB电极的电解电阻大大减小,实验结果表明,硬脂酸香豆素LB膜对n-Si/Ni电极上的光致电荷传递过程的修饰作用是良好的.