Surface Photovoltage Studies of Moisture Sensitive Characteristic of Copper Tetrasulfonato-Phthalocyanine

The surface photovoltaic characteristic of copper tetrasulfonato- phthalocyanine (CuTsPc) in water vapor was studied by surface photovoltage spectroscopy (SPS). It was found that the adsorption of water vapor caused some marvelous changes of the photovoltaic response, that is, the SPS signal diminished rapidly and even reversed; the bands were widened and displayed a bathochromic shift. The dependence of surface photovoltage on the vapor pressure indicates that the reversed signal reaches to a maximum when the vapor pressure is 4.7×102 Pa. The time response velocity, reversibility, selectivity and reproducibili-ty were examined as well. All results obtained show that CuTsPc is of great significance in the manufacture of moisture sensitive devices. In addition, the mechanism of moisture sensitivity is discussed.     

Preparation of sodium titanate nanotubes modified by CdSe quantum dots and their photovoltaic characteristics

Sodium titanate nanotubes have been prepared and modified chemically with CdSe quantum dots (QDs) using bifunctional modifiers (HS-COOH). Their photovoltaic characteristics have also been studied. The results indicate that the surface photovoltage response of nanotubes extends to the visible light region, and the intensity of surface photovoltage is enhanced after modification with CdSe QDs. The field-induced surface photovoltage spectroscopy (FISPS) shows that sodium titanate nanotubes have different photovoltaic response before and after modification. That is, the surface photovoltaic re-sponse of pure sodium titanate nanotubes increases with the enhancement of positive applied bias and decreases with the enhancement of negative applied bias. Meanwhile, the surface photovoltaic re-sponse of CdSe modified sodium titanate nanotubes is different from that of the pure sodium titanate nanotubes. The whole spectrum increases with the enhancement of applied bias at the first stage. However, when the applied bias reaches a certain value, the surface photovoltage response keeps in-creasing in some spectrum regions, while decreasing in other spectrum regions. This novel phe-nomenon is explained by using an electric field induced dipole model.     

不同焙烧气氛对氧化镁表面碱性的影响

The MgO samples are prepared by heating Mg(OH) 2 at 600 ℃ in different atmospheres. The XRD results show that Mg(OH) 2 is decomposed into MgO after calcination. The results of BET indicate that the specific surface area of the samples is affected by the calcination atmosphere, the sample preheated in vacuum has the highest surface area, while the sample preheated in air has the lowest surface area. The CO 2 TPD profiles of the samples are also different, which implies that the samples have different surface basicity. From the desorbed amount of CO 2 and the desorption activation energy, it is found that the sample pretreated in vacuum has the most basic sites and the strongest basicity.     

Numerical Study for the Role Playing of Atmospheric Dynamic Processes Caused by Seasonal and Non-seasonal Forcings in Formation of the Short-Term Anomalous Climate Change

In this paper, it has been pointed out that anomalous climate change can be found, which is similar to that caused by anomalous external forcing, in the 25-year simulations from the model without non-seasonal external forcings. It shows that the short-term anomalous climate change can be formed by dynamic processes in the atmosphere caused by seasonal and non-seasonal external forcings.In this research, two numerical experiments with different initial states and different time sub-series of the natural climate change have been done using the IAP atmospheric general circulation model with same sea surface temperature anomalies in the tropical Pacific. The results reveal that anomalous climate phenomena in the atmosphere can arise as a result of interaction between the inherent internal dynamic process (caused by seasonal external forcings) in the long-range climate natural change process of the atmosphere and the dynamic process caused by non-seasonal external forcings (external dynamic process); in the     

TiO2负载型催化剂及光催化还原CO2反应的表面光电压谱研究

The study of mechanism of modified TiO₂ photocatalysts for photoreduction of CO₂ with surface photovoltage spectrum(SPS) was reported for the first time．The results showed that a new surface photovoltaic response band appears in the SPS curve of Pd/TiO₂ or Pd/RuO₂/TiO₂ in near IR region,moreover,the stronger SPS response intensity in near IR is,the higher the catalytic activities of photoreduction of CO₂．The surface state plays a role in the process of photocatalysis．     

Surface photovoltage phase spectroscopy study of the photo-induced charge carrier properties of TiO2 nanotube arrays

By using the surface photovoltage(SPV) technique based on a lock-in amplifier,surface states located 3.1 eV below the conduction band of TiO 2 have been detected in TiO 2 nanotube arrays prepared by anodization of titanium foil in fluoride-based ethylene glycol solution.The photo-induced charge transportation behavior of TiO 2 nanotube arrays was also studied by qualitatively analyzing their SPV phase spectra measured under different external bias.When a negative bias was applied,carriers excited from surface states have the same transportation properties as those excited from the valence band;in contrast,when a positive bias was applied,these two kinds of photo-excited carriers exhibit different transportation behavior.     

Triplet-triplet annihilation upconversion materials as electrophoretic inks

Luminescent materials that can be reversibly switched by electric field stimulation are attractive since the potential application for optoelectronic devices. Here we report a triplet-triplet annihilation upconversion(TTA-UC) system with electrophoretic response which is developed as the electrophoretic ink. The TTA-UC system consists of an ionic derivative of 9,10-diphenyl anthracene(DPA) as the annihilator and Pt(II)octaethylporphyrin(PtOEP) as the sensitizer. Upon applying an electric field, ...     

DISPERSION STATE OF ZINC OXIDE ON SURFACE OF SILICA GEL AND SURFACE ACIDITY OF ZnO/SiO_2

The dispersion threshold level of zinc oxide on silica gel was determined by X-ray quantitative phase analysis. And the results of XPS experiments show that the surface of the sample is enriched with ZnO and there is a limit for the ZnO amount dispersed on the surface. The value of this limit is corresponding with the threshold level obtained by XRD. The measurements of surfaee acidity show that there are some stronger acid sites on the surface of ZnO/SiO_2, they have not been found on the ZnO or SiO_2 individually, and the total amount of acid increases remarkably. The acidity depends on the ZnO concentration in the surface phase and reaches the maximum at the threshold value.In this paper, we propose a new point of view for the origin of the acidity on surface of the ZnO/SiO_2 samples. ZnO is well dispersed on the surface of SiO_2 gel in a monolayer state. In this situation, some new surface structure units emerge as a result of interaction between dispersed ZnO and the carrier, which are responsible     

THE PRECURSOR OF INSTABILITY FOR NONLINEAR SYSTEMS AND ITS APPLICATION TO EARTHQUAKE PREDICTION

By analysing the instability process of various nonlinear systems, we conclude that their instability precursors are the continual heightening of the response rate or response ratio.Applying this theory to earthquake prediction, we adopt the periodical change of the stress in crust caused by the tide-generating force as the loading and unloading. If we can measure the ratio of the response (such as crust deformation, gravity and seismicity) during the loading period to that during the unloading period, this parameter must contain some characteristic information about the seismogenic process.With nine earthquakes (M≥7) data that occurred in Chinese mainland during 1970-1988, we take the sum of square root o?energy of small earthquakes, which is called the released strain by Benioff, as the response to the tidal loading and unloading. We find that the response ratios of seven earthquakes increase obviously before the main earthquakes.     

热分解双(2-氨基烟酸)锌(Ⅱ)制备的介孔微砖ZnO纳米颗粒的光催化活性(英文)

Hollow microblocks of [Zn(anic)_2], as a novel coordination compound, were synthesized using 2-aminonicotinic acid(Hanic) and zinc(Ⅱ) nitrate tetrahydrate. The chemical composition of the zinc complex, ZnC_(12)H_(10)N_4O_4, was determined by Fourier transform infrared(FTIR) spectroscopy and elemental analysis. The synthesized zinc complex was used as a precursor to produce ZnO nanostructures by calcination at 550 °C for 4 h. Morphological studies by scanning electron microscopy and transmission electron microscopy revealed the formation of porous microbricks of ZnO nanoparticles. N_2 adsorption-desorption analysis showed that the obtained ZnO microbricks possess a mesoporous structure with a surface area of 8.13 m~2/g and a pore size of 22.6 nm. The X-ray diffraction pattern of the final product proved the formation of a pure ZnO composition with a hexagonal structure. Moreover, FTIR analyses showed that the 2-aminonicotinic acid ligand peaks were absent after the calcination step. Diffuse reflectance spectroscopy was used to determine the band gap energy of the produced ZnO and it was about 3.19 eV. To investigate the photocatalytic activity of the porous ZnO nanostructure, a series of photocatalytic tests were carried out to remove Congo red, as a representative toxic azo dye, from aqueous solution. The results show that the product can be used as an efficient photocatalyst for waste water treatment with high degradation efficiency.     

活性粒子吸附对ZnO纳米粒子表面光伏特性的影响

作为一种传统的半导体,氧化锌在压电陶瓷、光电化学、光催化、发光器件以及气体传感器等方面具有广阔的应用前景,特别是氧化锌纳米粒子,由于其比表面积大、表面活性较高和对周围环境的敏感性,使其成为传感器研究领域中最有前途的材料,有关生物氧传感器和激光器的光电功能特性以及其能带结构的研究已有报道,     

ZnO/Cu2O异质结中深能级表面光伏特性

采用恒电压沉积法在导电玻璃(FTO)上制备了具有三棱柱金字塔状的ZnO/Cu2O异质结薄膜. 利用场发射扫描电镜(FESEM)与X射线衍射仪(XRD)对薄膜的微观形貌和晶体结构进行了表征. 利用表面光电压谱(SPS)、场诱导表面光电压谱(FISPS)和相位谱(PS)研究了单一Cu2O与ZnO/Cu2O异质结薄膜的表面光伏性质. 结果表明, 与单一Cu2O薄膜相比, ZnO/Cu2O异质结薄膜的光伏响应范围拓展到了600~800 nm. 根据SPS, FISPS和PS的作用原理, 拓展部分的光伏响应归因于ZnO/Cu2O异质结中Cu2O层的深能级跃迁, 该跃迁在ZnO-Cu2O界面电场(方向由ZnO指向Cu2O)的作用下得到加强, 同时深能级跃迁产生的电子-空穴对在ZnO-Cu2O界面电场的作用下得到了有效分离和传输.     

量子尺寸氧化锌颗粒的表面光电压谱研究

氧化锌是极少数几个可以实现量子尺寸效应的氧化物半导体材料[1 ] .传统上 ,这种材料广泛用于陶瓷、压电传感器、催化剂以及发光器件等领域 .随着量子尺寸氧化锌颗粒制备工艺日臻成熟 ,这类材料的应用进一步拓展到光电转换 [2 ] 、光催化[3] 以及化学传感器 [4] 领域 .而在这些领域中的应用都与颗粒的表面性质密切相关 .本工作中制备了两种不同粒径的氧化锌纳米微粒 ,利用表面光电压谱以及电场诱导表面光电压谱对颗粒的表面性质进行了研究 ,并对颗粒的表面态进行了具体指认 .1　实验部分氧化锌纳米微粒参照文献 [5 ,6 ]方法制备 .将 5 .49g…     

Photoinduced charge transfer in ZnO/Cu(2)O heterostructure films studied by surface photovoltage technique

ZnO/Cu(2)O heterostructure films were prepared by a two-step electrodeposition method in aqueous solution on fluorine-doped tin oxide (FTO) substrates. Scanning electron microscopy (SEM), X-ray powder diffraction (XRD) and UV-vis transmission measurements were utilized to characterize the films. Surface photovoltage (SPV) technique was used to investigate the process of photoinduced charge transfer. The results show that there is an electric field located at the interface between ZnO and Cu(2)O film and the photoinduced electrons in Cu(2)O film inject into ZnO under the effect of interfacial electric field with visible light irradiation. While under ultraviolet light illumination, the photoinduced electrons in Cu(2)O film accumulate at the surface of Cu(2)O film instead of injecting into ZnO under the action of surface built-in electric field of Cu(2)O film. The work function measurements confirm that the direction of interfacial electric field is from ZnO to Cu(2)O. These results are help to future design of high performance heterostructure photovoltaic devices.     

取代基对偶氮类颜料光伏特性的影响

偶氮类材料由于其具有成本低、来源丰富、易于加工以及可以通过接不同性质的取代基得到不同性能的光电导体等优点 ,作为光接受器材料 ,其导电类型、光生电荷及传输过程以及光照后表面电荷的种类在静电复印、激光打印中起着决定性的作用 [1～ 3] .由于取代基会影响偶氮类材料的费米能级 (电子填充水平 ) ,从而影响其导电类型 .如何判断其导电类型以及光照后表面电荷的种类还是一个难题 .本文首次利用 SPS(表面光电压谱 )和 FISPS(场诱导表面光电压谱 )技术对几种具有不同取代基的双偶氮类有机颜料的光伏特性进行了研究 ,发现取代基对它们…     

Mn(II)配合物的晶体结构及表面光电性能

采用水热法合成3个新的Mn(II)配合物[Mn(SO₄)(H₂O)₃]_n (1), [Mn2.5(HPO₄)(PO₄)(H₂O)₂]_n (2), [Mn(phen)₂(H₂O)₂]·(C₄H₄O₄)·4H₂O (3) (phen=1,10-邻二氮杂菲). 用X射线单晶衍射、表面光电压光谱(SPS)、红外光谱(IR)、紫外-可见吸收光谱(UV-Vis)、电子顺磁共振谱(EPR)对配合物进行了表征. 结构解析表明: 配合物1是具有2D结构的配合物, 氢键将其连接成3D超分子; 配合物2是具有3D无限结构的配合物; 配合物3是单核配合物, 再由多种氢键连接, 形成3D超分子. SPS结果表明, 3个配合物在300-800 nm范围内都呈现明显的光伏响应, 表明它们均具有一定的光-电转换性能. 讨论了配合物结构, 空间维度和中心金属离子配位环境的不同对配合物表面光电性能的影响以及SPS与UV-Vis的关联: 配合物的结构维度越高、规则性越好, SPS响应强度越大; 中心金属离子的直接配位原子种类的不同、所处外晶场的强弱不同, SPS响应带的数目和位置明显不同.     

Rup_2P表面敏化TiO_2基复合薄膜光致界面电荷转移

采用离子束溅射技术制备出TiO2/ITO、Zn2+掺杂的TiO2(TiO2-Zn)/ITO和TiO2/ZnO/ITO薄膜,采用表面敏化技术和旋转涂膜法,制备出(1,10-邻菲咯啉)2-2-(2-吡啶基)苯咪唑钌混配配合物(Rup2P)表面敏化的TiO2基复合薄膜Rup2P/TiO2/ITO、Rup2P/TiO2-Zn/ITO和Rup2P/TiO2/ZnO/ITO.表面光电压谱(SPS)结果发现:敏化后的TiO2基薄膜在可见区(400-600nm)产生SPS响应;TiO2基薄膜的能带结构不同,其在400-600nm和350nm处的SPS响应的峰高比不同.利用电场诱导表面光电压谱(EFISPS),测定TiO2基薄膜和表面敏化TiO2基复合薄膜各种物理参数,并确定其能带结构.分析可知,表面敏化TiO2基复合薄膜在400-600nm的SPS响应峰主要源于Rup2P分子的中心离子Ru4d能级到配体1,10-邻菲咯啉π*1和2-(2-吡啶基)苯咪唑π*2能级的跃迁;TiO2中Zn2+掺杂能级有利于Ru4d能级到配体π*1和π*2跃迁的光生电子向TiO2-Zn导带的注入;TiO2/ZnO异质结构有利于光生电子向ITO表面的转移,从而导致可见光(400-600nm)SPS响应增强以及光电转换效率的提高.     

In situ growth of ZnO nanocrystals from solid electrospun nanofiber matrixes

Porous fiber membranes consisting of 1D assemblies of ZnO nanocrystal-supported poly(vinyl alcohol) (PVA) nanofibers are described. These hybrid nanofiber membranes were assembled by first electrospinning a ZnO precursor-containing PVA aqueous solution. Subsequently, the electrospun composite nanofibers were submerged in a basic ethanol solution. As a result, ZnO precursors in solid PVA matrixes were hydrolyzed to generate ZnO crystals residing on the fiber surfaces. Photoluminescence spectroscopy analysis demonstrated the as-hydrolyzed fiber membranes possess white luminescence. Furthermore, the ZnO-encapsulated PVA nanofibers were prepared by directly electrospinning a ZnO nanocrystal-containing PVA solution as the contrast of the as-hydrolyzed hybrid nanofibers. The surface photovoltage spectroscopy (SPS) confirmed that the as-hydrolyzed hybrid fiber membranes had a strong SPS response, but the directly spun fiber membranes did not have any SPS response. This can be attributed to the favorable structure of the hydrolyzed hybrid nanofibers, that is, the surface residence of ZnO permits ZnO crystals to make direct contact with ITO electrodes to transfer the photogenerated electron originating from ZnO to ITO electrodes. By contrast, the transfer of the photogenerated electron is limited by PVA matrixes in the directly spun fiber system.     

Mn(Ⅱ)配位聚合物的合成、结构及光物理性能

采用水热方法合成了2种结构新颖的Mn(Ⅱ)配位聚合物,[Mn(m-tpha)(phen)]_n(1),{[Mn₃(m-tpha)₂(m-Htpha)₂(bipy)₂]·3H₂O}_n (2),(m-H₂tpha=间苯二甲酸,phen=1,10-邻菲咯啉,bipy=2,2′-联吡啶)。通过X-射线单晶衍射、红外光谱(IR)、紫外光谱(UV-Vis)、表面光电压光谱(SPS)和场诱导表面光电压光谱(FISPS)等方法对配聚物进行了表征。结构分析表明:配聚物(1)和(2)均是通过间苯二甲酸根桥连的具有1D无限结构的Mn(Ⅱ)配聚物。不同的是(1)的不对称单元中只包含1个Mn(Ⅱ)离子,它采取了N₂O₄的配位模式;而(2)的重复单元中,包含3个Mn(Ⅱ)离子,其中有2个Mn(Ⅱ)离子是晶体学等效的,它们也采取了N₂O₄的配位模式,另1个Mn(Ⅱ)离子处于一个几乎规则的正八面体场的配位环境中,6个配位原子均为O。配聚物的表面光电压光谱测试表明,它们在300～800 nm范围内都呈现正的表面光伏响应(SPV),但是光伏响应带的强度、数量是明显不同的。这是它们的结构、中心金属Mn(Ⅱ)离子的配位微环境不同所致。将配聚物的SPS与其UV-Vis光谱进行对比,可以看出SPS响应带与UV-Vis吸收峰基本是对应的。     

SPS法研究ZnTPP对TiO_2的光谱敏化

本文利用表面光电压谱(Surface Photovohage spectroscopy,简称SPS)研究了ZnTPP对TiO_2粉末的光谱敏化,发现用ZnTPP修饰后的TiO_2(金红石和锐钛矿)粉末在可见区420、550和590nm附近有三个光伏响应带,它们分别对应于ZnTPP的Soret、Q(1,0)和Q(0,0)带。经过严格的实验和分析,证明这三个带是由ZnTPP对TiO_2的敏化光电压引起的,而不是ZnTPP自身的光伏响应。在敏化效果上,亚稳的锐钛矿优于金红石。同时,我们对这种光敏表面的光诱导电荷转移机制和SPS作为一种研究光谱敏化方法的可行性进行了讨论。