不同波长紫外光照下纳米TiO2薄膜的光致亲水性与循环伏安行为

通过溶胶-凝胶方法分别在ITO和玻璃表面制备了纳米TiO_2薄膜，研究了纳米 TiO_2薄膜在254及365nm的紫外光照射下的循环伏安行为和光致超亲水性。在紫外 光的照射下，TiO_2薄膜电极可表现出两个光电化学过程，纳米TiO_2薄膜的光致超 亲水性转变及两个光电化学过程的速率均取决于紫外光的波长，原因在于纳米 TiO_2薄膜对两种波长的光的吸收率和光子的能量不同。提出了光电化学过程的机 理，认为紫外光照射下纳米TiO_2薄膜的超亲水性变化与产生Ti~(3+)的过程引起的 表面微观结构变化存在的一定的内在联系。     

紫外光下纳米TiO2 薄膜亲水性机理的电化学研究

The nanometer films of TiO2 were prepared by sol-gel method on ITO（Indium-tin oxide,SnO2:In） substrate. The TiO2 film was the anatase phase with a particle size of 100 nm from the measurements of X-ray diffraction and AFM（Atomic-Force-Microscope）. Electrochemical characteristics of ITO/ TiO2 electrode under UV（ultraviolet）irradiation were investigated using the method of cyclic voltammetry. A new oxidative peak was observed at 0.035 V when the TiO2 electrode was irradiated by 253.7 nm UV light for a certain time. The peak current increased with the irradiation time. It was assumed that the new oxidative peak resulted from Ti3+,which was formed during the UV illumination. The changes of hydrophilicity of the TiO2 thin film on ITO under UV light were also observed. It was assumed that the changes of hydrophilicity of the films may be related with the formation of Ti3+ on the surface when the film was irradiated by UV light.     

射频磁控溅射制备纳米TiO2薄膜的光电化学行为

在室温下采用射频磁控溅射法制备了纳米晶粒的TiO2薄膜,用循环伏安法研究了ITO/TiO2薄膜电极的光电化学行为,并测量了相应TiO2薄膜的亲水性与光催化能力.结果表明,在室温下制备的TiO2薄膜为无定形结构,当退火温度超过400 ℃时转化为锐钛矿结构.在400 ℃下退火的TiO2薄膜具有良好的亲水性和光催化能力. TiO2薄膜电极用254 nm的紫外光照射一定时间后会产生新的氧化峰,且随着光照时间的增加,峰电流也增加.初步认为用紫外光照射一定时间后, TiO2薄膜的循环伏安图的氧化峰属于光生的Ti3＋,而光致亲水性可能与Ti3＋的生成有关.     

Cyclic Voltammetric and Ac Impedance Behavior of TiO2 Electrodes under UV Illumination

Electrochemical behavior of an ITO/TiO₂ electrode both under ultraviolet (UV) illumination and in the dark was investigated using the methods of cyclic voltammetry and ac impedance spectroscopy. A new oxidative peak is observed at 0.15 V when the TiO₂ electrode was illuminated by UV light for a certain time. The peak current and the anodic photocurrent increased with the increase of UV light intensity. It is assumed that the new peak belonging to the oxidation of Ti³⁺, which was formed on the electrode surface during the UV illumination. It is also found that the apparent resistance was decreased but the capacitance was increased when the TiO₂ electrode was illuminated by UV light according to the measurement results of ac impedance. Based on the results in this paper, it was directly proved that Ti³⁺ was actually formed when the electrode was irradiated by UV light.     

紫外光照下纳米TiO2电极的电化学行为

通过电沉积方法制备了纳米TiO2薄膜电极，应用循环伏安和交流阻抗技术研究了TiO2电极在253.7 nm的紫外光照射下的电化学行为.结果表明, TiO2薄膜电极的循环伏安图在＋0.15 V处出现新的氧化峰,交流阻抗谱的半圆明显减小，电极的开路电位在有光和无光的情况下呈现规律变化.实验证实在紫外光照射下电极表面有新物种Ti3＋生成，但光生Ti3＋不稳定.     

染料敏化TiO2/WO3薄膜电池的光电变色

The light-to-electricity conversion process of the TiO2 nanostructured electrode sensitized by a dye was investigated using the photoelectrochemical method in this paper. At the same time, the WO3 thin film was electrodeposited on conducting glass. The results showed that the dye-sensitized nanoporous TiO2 film has the properties of energy conversion, along with good electrochromic properties of electrodeposited MoO3 thin film. A self-powered smart window was achieved by combining a dye-sensitized nanoporous TiO2 film as the photovoltaic layer and an electrodeposited WO3 film as the electrochromic layer. This window changed from being almost transparent to blue spontaneously under illumination, and thus could modulate light transmittance.     

纳米结构TiO2/聚3-己基噻吩多孔膜电极光电性能研究

用光电流作用谱、光电流-电势图等光电化学方法研究了ITO/聚3-己基噻吩(ITO/ P3HT)膜和纳米结构TiO2/聚3-己基噻吩(TiO2/P3HT)复合膜的光电转换性质. 结果表明, P3HT膜的禁带宽度为1.89 eV, 价带位置为－5.4 eV. 在ITO/TiO2/ P3HT复合膜电极中存在p-n异质结, 在一定条件下异质结的存在有利于光生电子-空穴对的分离. P3HT修饰ITO/TiO2电极可使光电流发生明显的红移, 从而提高了宽禁带半导体的光电转换效率.     

TiO2-MoO3复合纳米管阵列薄膜的制备及其可见光活性

通过阳极氧化的方法制备TiO₂纳米管薄膜, 在MoO₃存在的条件下对该薄膜进行热处理得到TiO₂-MoO₃复合纳米管阵列薄膜. 利用X射线衍射(XRD), 扫描电子显微镜(SEM), X射线光电子能谱(XPS), 电化学阻抗谱(EIS), Mott-Schottky 及光电化学方法对得到的薄膜进行了表征. XRD结果表明, TiO₂-MoO₃复合纳米管薄膜中的TiO₂主要为锐钛矿晶型. SEM实验证实了薄膜纳米管结构的存在, 样品中的MoO₃均匀地分散在TiO₂纳米管表面. 利用XPS方法分析了TiO₂-MoO₃复合纳米管薄膜元素的组成, 结果表明, MoO₃在TiO₂表面形成TiO₂-MoO₃复合纳米管薄膜. 研究了热处理温度以及热处理时间对样品的光电化学性能的影响, 相对于单纯TiO₂纳米管薄膜, 适量引入MoO₃提高了样品在可见光区的光电响应能力, 样品的平带电位负移. 在450 °C热处理60 min制得的TiO₂-MoO₃复合半导体纳米管阵列薄膜光电响应活性最高.     

聚3-甲基噻吩修饰量子点硫化铅连接TiO2纳米结构膜的光电化学研究

采用原位化学法在纳米结构TiO2电极上制备了量子点PbS(Q-PbS), 并用电化学方法在TiO2/Q-PbS表面聚合3-甲基噻吩[poly(3-Methylthiophene), PMeT]. 研究结果表明, PMeT和Q-PbS单独修饰纳米结构TiO2电极和PMeT修饰Q-PbS连接纳米结构TiO2电极的光电流产生的起始波长都向长波方向移动; 在可见光区光电转换效率均比纳米结构TiO2的光电转换效率提高显著; PMeT与Q-PbS修饰的纳米结构TiO2之间存在p-n异质结. 在一定条件下p-n异质结的存在有利于光生电子/空穴的分离, 提高了光电转换效率.     

石墨烯氧化物薄膜电极的光电化学特性

采用浸渍-提拉法制备了一系列石墨烯氧化物(GO)薄膜,并通过X射线衍射(XRD),扫描电镜(SEM),傅里叶变换红外光谱,紫外-可见吸收光谱和光电化学测量等技术对样品进行了表征.在GO电极上观察到阴极光电流,且光电流密度受薄膜的厚度影响.GO薄膜电极厚度为27nm时,光电流密度为0.25μA·cm-2.此外,GO电极的光电响应还受紫外光照影响,随着紫外光照时间的延长,阴极光电流逐渐减小.该工作提供了简便的通过控制薄膜厚度或紫外光照时间来控制GO薄膜半导体光电化学性能的方法.     

阳极氧化TiN薄膜制备N掺杂纳米TiO2薄膜及其可见光活性

室温下通过电泳沉积(EPD)的方法在Ti片表面制备TiN薄膜, 然后对TiN薄膜进行阳极氧化得到N掺杂多孔纳米结构的TiO2薄膜. 利用X射线衍射(XRD), X射线光电子能谱(XPS), 扫描电子显微镜(SEM)及光电化学方法对得到的薄膜进行表征. XRD测试结果表明, 经过阳极氧化并在350 ℃空气气氛中退火1 h的薄膜中存在锐钛矿晶型的TiO2. XPS的结果表明, 样品中的N元素取代部分O, 且N的摩尔分数为0.95%. SEM显示, 经阳极氧化后薄膜表面出现多孔纳米结构. 光电化学测试结果显示, 阳极氧化提高了N掺杂TiO2薄膜在可见光下的光电响应. 经阳极氧化并热处理的薄膜在0 V电位及可见光照射下光电流密度为2.325 μA·cm-2, 而单纯热处理的薄膜在相同条件下光电流密度仅为0.475 μA·cm-2. 阳极氧化得到纳米多孔结构提高了N掺杂纳米TiO2薄膜的表面积, 从而对可见光的响应增大.     

Nitrogen-doped TiO2 from TiN and its visible light photoelectrochemical properties

Homogeneous titanium nitride (TiN) thin film was produced by simple electrophoreic deposition process on Ti substrate in an aqueous suspension of nanosized TiN powder. Nitrogen-doped titanium dioxide (TiO_2−xN_x) was synthesized by oxidative annealing the resulted TiN thin film in air. Photoelectrochemical measurements demonstrated visible light photoresponse for the electrode of annealed electrophoreic deposited TiN samples. It is found that the synthesized TiO_2−xN_x electrode showed higher photo potential under white and visible light illumination than the pure TiO₂ electrode. The photocurrent under visible light illumination was also observed, which increased with the increase of deposition time of TiN thin films.     

3-己基噻吩和2-噻吩甲酸共聚物修饰纳米结构TiO2薄膜电极的光电性能研究

用光电流作用谱、光电流-电势图等光电化学方法研究了铟锡导电玻璃(ITO)/3-己基噻吩和2-噻吩甲酸共聚物(CTCHT)膜电极以及ITO/TiO₂/3-己基噻吩和2-噻吩甲酸共聚物(CTCHT)复合膜电极的光电转换性质. 结果表明, CTCHT膜为p-型半导体, 禁带宽度为2.44 eV, 价带位置为－5.73 eV. 研究表明在ITO/TiO₂/CTCHT复合膜电极中存在p-n异质结, p-n异质结的存在能够使光生电子和空穴有效的分离, 有效地降低了电荷的反向复合几率, 提高了光电转换效率, CTCHT膜修饰ITO/TiO₂电极可使光电流增强, 使宽禁带半导体电极的光电转换效率得到改善.     

Selenium-modified titanium dioxide photochemical diode/electrolyte junctions: photocatalytic and electrochemical preparation, characterization, and model simulations

The photoelectrochemical behavior of TiO2 thin film electrodes, photocatalytically modified with Se islands, is described. The TiO2 thin films were electrodeposited on transparent conducting oxide glass substrates. The resultant electrode forms a n-TiO2/p-Se "photochemical diode" which, in turn, contacts an electrolyte phase. Both transient photocurrent profiles (in response to excitation light that is switched on or off) and steady-state current-potential curves in response to chopped irradiation are considered. We show that the relative dominance of the contributions from the TiO2 and Se components to the overall response of the photochemical diode/electrolyte junction crucially depends on the wavelength distribution of the excitation light source. A simple equivalent circuit representation of this junction is presented, comprised of a photodiode in parallel with two photodiodes connected in series back-to-back. Simulations of the transient and steady-state photoelectrochemical response of this system are presented, and are shown to be in good agreement with the corresponding experimental profiles.     

热对银电极阳极膜光电流测定的影响

利用光电流 ,光热信息和热电流方法研究了热对Ag在 1mol/LNaOH溶液中表面阳极膜光电流的影响 .所用光源为 4 88nm和 5 32nm的激光 .结果表明Ag2 O层具有半导体光电流特性 ,在Ag ,Ag2 O和AgO的转变过程中 ,光照下电极表面的温升不同 .对照循环伏安曲线 ,及光电流和热电流曲线 ,可以证明在电位朝负方向扫描过程中于 0 .37V出现的阳极光电流峰和 0 .1V出现的阴极光电流峰主要是由光照下温度升高引起的热电流所造成的 .光电流和热电流随着光强度的增强而线性增强     

Size effects of gold nanaoparticles on plasmon-induced photocurrents of gold-TiO2 nanocomposites

An ITO electrode was coated with a nanoporous TiO2 film, and the film was loaded with Au nanoparticles with different diameters (15, 40 and 100 nm). The electrode exhibited plasmon-induced photocurrents in the presence of Fe(2+/3+) couple under visible light (lambda > 420 nm). The quantum efficiency increased with increasing particle size, whereas the maximum photocurrent density decreased.     

TiO_2-CuPcTs敏化薄膜光电流及可见光光催化性能

以四磺酸酞菁铜(CuPcTs)为敏化剂,玻璃和图案化的氧化铟锡(ITO)分别作为基底,制备了敏化薄膜TiO2-CuPcTs和ITO/TiO2-CuPcTs/ITO敏化器件.以罗丹明B(RhB)的可见光光催化降解为模型反应评价敏化薄膜的光催化性能.敏化薄膜采用UV-vis和Raman技术进行表征,同时利用敏化器件的结构特性,测定其在氮气和纯水体系下的光电流.研究结果表明,TiO2-CuPcTs可以有效地将光谱响应拓宽到可见光区,一级反应速率常数为空白TiO2薄膜的3.7倍.TiO2-CuPcTs薄膜光催化降解RhB的重复性能稳定.与ITO/TiO2/ITO器件相比,敏化器件ITO/TiO2-CuPcTs/ITO具有较高的光电流信号,验证了激发态的CuPcTs能够将电子转移到TiO导带上的敏化机理.     

五甲川菁染料敏化p-NiO纳米结构电极的光电化学

研究了NiO纳米结构电极及五甲川菁染料敏化NiO纳米结构电极的光电化学行为。结果表明,NiO纳米结构电极在光照下产生阴极光电流,为p-型半导体,其禁带宽度为2.8eV,使用五甲川菁染料敏化可以显著地提高NiO纳米结构电极的阴极光电流,使NiO纳米结构电极吸收波长红移至可见光区,光电转换效率得到明显改善。研究了OTE/TiO~2/Ru(bpy)~2(SCN)~2和OTE/NiO/PMC作为光阳极和光阴极组成电池的电池特性,结果表明复合电池的光电压提高,但光电流的大小受光电流小的电极限制。     

不同取代基卟啉衍生物敏化纳米TiO2多孔膜电极的光电性质研究

采用含有不同取代基的卟啉衍生物四羟基苯基卟啉(THPP)和四羧基苯基卟啉(TCPP)分别对纳米TiO2多孔膜电极进行敏化.对两种敏化电极进行了UV-Vis光谱、FTIR光谱和X射线光电子能谱(XPS)测试.结果表明,TiO2与TCPP的作用比与THPP的作用强.在相同浸泡条件下,TiO2电极吸附TCPP的量大于吸附THPP的量.将两种敏化电极分别组装成光电化学电池,从正背两个方向照射光电池,研究它们在不同照射方向下的光电流响应.从光电化学电池的I-V曲线计算TCPP敏化的光电化学池的总光电转换效率(η)为0.13%,而THPP敏化的光电化学电池的η为0.06%.