聚3-甲基噻吩修饰量子点硫化镉连接纳米结构TiO2复合膜电极光电化学研究

采用原位化学法在纳米结构TiO2电极上制备了量子点CdS(Q-CdS),并用电化学方法在TiO2/QCdS表面聚合3-甲基噻吩po1y(3-Methylthiophene)(PMeT).通过对PMeT修饰Q-CdS连接TiO2纳米结构膜的研究表明,PMeT和Q-CdS单独修饰纳米结构TiO2电极和PMeT修饰Q-CdS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;一定条件下在可见光区光电转换效率均较纳米结构TiO2的光电转换效率有明显的提高;聚3-甲基噻吩(PMeT)与Q-CdS连接的纳米结构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.     

不同晶型 CdSe纳米棒的制备及光电性能研究

采用水热法制备了不同晶型CdSe纳米棒,并用TEM、SEM、XRD、TGA-DTA对其进行了表征.结果显示反应温度为240℃生成纤锌矿型CdSe纳米棒,反应温度为200℃生成闪锌矿型CdSe纳米棒.并对纳米棒进行了光电性能测定,纤锌矿型CdSe纳米棒膜电极的光电转换效率（IP.CE）优于闪锌矿型CdSe纳米棒膜电极的IPCE.CdSe/PMeT复合膜电极在具有最大光电转换效率时的波长发生了红移.     

p-n异质结NiO/TiO2纳米复合材料的构建及应用研究进展

TiO_2和NiO分别作为n型和p型半导体材料,通过复合构建p-n异质结NiO/TiO_2纳米复合材料可以促进光生电子-空穴对的分离,从而提高光电性能。综述了不同形貌的p-n异质结NiO/TiO_2纳米复合材料的构建,如纳米球、纳米棒和纳米带等,以及其在光催化、锂离子电池、染料敏化太阳能电池和传感器等领域中的最新研究进展。     

P3HT及CTCHT修饰纳米TiO2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聚3-己基噻吩(P3HT)及3-己基噻吩和2-噻吩甲酸共聚物(CTCHT)修饰纳米结构TiO2电极的光电转换性质。结果表明,经修饰后的纳米TiO2电极光电流明显增强,光电转换效率得到明显提高。在复合膜电极中存在p-n异质结,异质结的存在有利于光生电子-空穴对的分离,降低了电荷的反向复合几率,提高了光电转换效率。     

CdSe/SiO2复合微球的光电性及在安培型生物传感器中的应用

利用介孔材料纳米孔道作为微反应器,将带正电荷的Cd离子与介孔二氧化硅(SiO2)表面带有负电荷的-SiOH相互静电吸附生成Cd-O-Si,然后采用低温方法使其与SeSO32-反应,缓慢生长,形成CdSe纳米晶.XRD和高倍透射电镜说明介孔孔道中生成了CdSe纳米颗粒.利用CdSe/SiO在UV激发下产生光电流的特性,用得到的CdSe/SiO复合微球作载体固定辣根过氧化物酶HRP,在OTE涂上一层HRP/CdSe/SiO2膜,应用到H2O2生物传感器的检测.过氧化物酶-电极系统内,在紫外光(UV)365nm波长照射下,由CdSe/SiO2产生的光电子和电极提供的电子同时对H2O2进行还原,产生的空穴被CdSe和SiO2的界面捕获,提高了反应速度.     

Ti O2纳米管阵列基底退火温度对CdSe/Ti O2异质结薄膜光电化学性能的影响

通过电化学沉积法以TiO2纳米管阵列(TNTs)为基底制备CdSe/TiO2异质结薄膜。研究TiO2纳米管阵列基底不同退火温度(200,350,450,600℃)对CdSe/TiO2异质结薄膜光电化学性能的影响。采用SEM,XRD,UV-Vis,电化学测试等方法对样品的微观形貌、晶体结构、光电化学性能等进行表征。结果表明:立方晶型的CdSe纳米颗粒均匀沉积在TiO2纳米管阵列管口及管壁上。TiO2纳米管阵列未经退火及退火温度为200℃时,为无定型态,在TiO2纳米管阵列上沉积的CdSe纳米颗粒数量少,尺寸小,异质结薄膜光电性能较差,光电流几乎为零。随着退火温度升高到350℃,TiO2纳米管阵列基底开始向锐钛矿转变;且沉积在TiO2纳米管上的CdSe颗粒增多,尺寸增大,光电化学性能提高。退火温度为450℃时光电流值达到最大,为4.05mA/cm^2。当退火温度达到600℃时,TiO2纳米管有金红石相出现,CdSe颗粒变小,数量减少,光电化学性能下降。     

CdSe纳米棒的制备及光电性能研究

采用水热法制备了CdSe纳米棒,并用TEM、SEM、XRD、TGA-DTA对其进行了表征.结果表明,纳米棒直径在100nm左右,长度约300nm;纳米棒具有闪锌矿的结构;将CdSe纳米棒均匀涂在导电玻璃的导电面上,在400℃下煅烧30min后制备成纳米棒膜电极,并进行了光电化学研究,纳米棒膜结构电极最高单色光的光电转换效率(IPCE)可达74%.     

自供能ZnO/ZnS异质结紫外探测器的性能研究

用化学浴法在ZnO纳米棒表面沉积ZnS制备出ZnO/ZnS核壳纳米棒阵列,使用SEM、XRD和XPS等手段表征了样品的形貌、结构和成分。结果表明,ZnO/ZnS核壳纳米棒阵列表面粗糙,生长致密、分布均匀,其平均直径约为150 nm。以Pt为对电极组装的自供能ZnO/ZnS异质结紫外探测器,对紫外光具有很好的探测性能,能循环工作且性能稳定。这种探测器对微弱的紫外光也有较强的响应和较高的光敏性,且随着光强度的提高光电流密度线性增大。与自供能ZnO纳米棒紫外探测器相比,ZnO/ZnS异质结紫外探测器具有更高的响应速度,上升时间和下降时间分别提高到0.02 s和0.03 s。     

水溶液法制备CdSe和ZnSe纳米棒

用水溶液法直接合成了水溶性、发荧光的ZnSe和CdSe纳米棒。ZnSe纳米棒的直径约20～30nm,长度可达60～70nm;CdSe纳米棒的直径约30～60nm,长度可达150～450nm。用X射线衍射仪(XRD)、透射电镜(TEM)、高分辨透射电镜(HR-TEM)、荧光仪等仪器对纳米棒进行了表征。XRD和HRTEM的结果显示纳米棒具有立方结构,结晶度较高。讨论了纳米棒的形成机理以及pH对纳米棒发光强度的影响。合成的纳米棒在水溶液中至少稳定半年,表面被氨基和羧基化,在生物分析中具有广泛的应用前景。     

ZnO纳米团簇与CdSe纳米棒复合膜的光电化学性能研究

用水热法合成了粒径均匀、分散良好的花状ZnO纳米团簇和CdSe纳米棒.讨论了ITO/ZnO/CdSe复合膜电极光电性能的影响因素,对比研究了ITO/ZnO纳米团簇及ITO/CdSe纳米棒膜电极的光电化学性能,实验表明:复合膜电极拓展了在长波方向的光吸收,提高了光电转换效率;当ZnO与CdSe复合摩尔比为1∶3时,ITO/ZnO/CdSe纳米复合膜电极在本实验中得到最高光电转换效率(IPCE)25.27%,远远高于单一ITO/ZnO花状纳米团簇膜电极和ITO/CdSe纳米棒膜电极.     

TiO2/CdSe纳晶复合薄膜电极的光电性能研究

研究了TiO2/CdSe纳晶复合薄膜电极的瞬态光电流、光电流作用谱、光吸收特性,结果表明TiO2/CdSe纳晶复合薄膜电极阻止了CdSe上光生电子和空穴的复合,从而提高了阳极光电流的响应,获得了较高增幅的稳态光电流.     

CdSe纳晶薄膜电极的制备及其光电性能研究

利用化学溶液沉积法制备了CdSe纳晶薄膜,并用透射电子显微镜和扫描电子显微镜的EDS对其形貌和化学组成进行了表征.对CdSe纳晶薄膜电极的吸收光谱和光电性能进行了测试,结果表明,CdSe纳晶薄膜可以获得较好的光电流,这种薄膜电极改进后,可用于制作敏化太阳能电池的光阳极.     

Size-dependent absorption and defect states in CdSe nanocrystals in various multilayer structures

GeS2-CdSe superlattices and composite films are prepared by consecutive thermal evaporation of CdSe and GeS2 in vacuum. CdSe layer thickness varies between 1 and 10 nm, while the thickness of GeS2 layers is either equal (in superlattices) to or 20 times greater (in composite films) than that of CdSe layers. Standard spectral photocurrent measurements and various constant photocurrent methods are used to study optical absorption of all samples. An overall blueshift is observed with decreasing CdSe layer thickness of superlattices. This shift is related to a size-induced increase of the optical band gap of CdSe due to one-dimensional carrier confinement in the continuous nanocrystalline CdSe layers. A number of features are observed in the absorption spectra of composite films containing CdSe nanocrystals with average radii of approximately 2.5 and approximately 3.3 nm. They are discussed in terms of three-dimensional carrier confinement and are considered a manifestation of excited electron states in CdSe nanocrystals embedded in GeS2 thin film matrix. In addition to these discrete features, the exponential dependence of the optical absorption (Urbach) edge indicates a distribution of "valence band" tail states associated with disorder. Transient photoconductivity measurements made on similarly prepared SiOx-CdSe superlattices exhibit a rapid fall in photocurrent by a power law decay over several orders of magnitude of time, which is consistent with multi-pletrapping transport via an extensive distribution of deep defects.     

Room temperature ferromagnetism in solvothermally synthesized pure CdSe and CdSe:Ni nanorods

We report here room temperature ferromagnetism in CdSe and Ni-doped CdSe nanorods. Pure and 3% Ni-doped CdSe nanorods are synthesized by using low temperature solvothermal process by using ethylenediamine as solvent. X-ray diffractogram depicts the wurtzite (hexagonal) structure of the CdSe nanorods. From Transmission Electron Microscopy analysis, it is found that the average diameter of the CdSe nanorods is about 4–5 nm having length of about 50 nm. Magnetic studies are made by the analysis of M–H curves, obtained by using Superconducting Quantum Interference Device. The room temperature ferromagnetic behaviour has been shown by both pure CdSe as well as Ni-doped CdSe nanorods.     

Pt／n—n＋-Si电极上化学沉积铁氰化镍薄膜及其应用

在表面外延生长9μm的n型层的磷重掺杂的硅基底n—n＋一Si）结构上沉积约40nm铂（Pt）,经氩气保护673K热处理30min作为半导体电极（Pt／n—n＋-Si）。将半导体电极和铁氰化钾、硫酸镍以及硝酸钠的溶液接触,沉积出稳定的铁氰化镍（NiHCF）薄膜。复合电极与Pt电极组成光电化学电池,在零偏电压条件下,通过测量该电池的光电流可检测过氧化氢。通过循环伏安和X-光电子能谱对NiHCF薄膜进行了分析与表征。     

透明纳米TiO2薄膜的制备及其紫外光电特性研究

采用溶胶-凝胶法于ITO导电玻璃和石英玻璃基底上制备了均匀透明的TiO2多孔纳米薄膜.XRD和AFM测试结果表明,构成薄膜的TiO2粒子为锐钛矿相,粒径约为50nm.紫外-可见(UV-vis)吸收光谱显示,制得的TiO2薄膜对紫外光表现出很强的吸收特性.借助标准三电极体系进行的光电化学测试结果表明,在紫外光照射下,制得的薄膜电极可产生稳定的阳极光生电流,且电流大小显著依赖于照射光的波长(λ),λ=320nm的光产生的光电流最大.另外,薄膜电极中的光电流大小与电极电位(U)有关.高于0.6V的电位可有效抑制光生电子向电解液的注入,并增大光生电子向导电基底的扩散速度,从而提高阳极光电流的大小.实验结果表明,纳米TiO2薄膜在紫外光传感器的制备方面具有较好的应用潜力.     

Morphological study of nanoparticle-polymer solar cells using high-angle annular dark-field electron tomography

Electron tomography in high-angle annular dark-field scanning transmission electron microscopy (HAADF-STEM) mode is used to image networks of nanoparticles within polymer-nanoparticle blend photovoltaic devices. Blends of CdSe nanoparticles (～6.5 nm diameter spheres and ～33 nm long nanorods) with poly[2-methoxy-5-(3',7'-dimethyloctyloxy)-1,4-phenylene vinylene] (OC(1)C(10)-PPV) are investigated. Blends using spherical particles are found to contain aggregated regions in which well-connected networks of nanoparticles exist, surrounded by lower-density regions with poorer connectivity. As the ratio of nanoparticles to polymer is increased the aggregated regions increase in size, and the connectivity of the particles in the lower-density regions also increases. This has the effect of increasing the overall percentage of the charge-generating interface connected to the electron-collecting electrode, consistent with the trends observed in device performance. Using nanorods instead of spherical particles results in a highly connected network of particles distributed homogeneously through the film. The nanorods are oriented close to parallel to the plane of the film.     

Photoelectrochemical performance of CdS nanorods grafted vertically aligned TiO2 nanorods

In this study, TiO₂ nanorods/CdS nanorods composite samples were successfully synthesized by grafting CdS nanorods on vertically aligned TiO₂ nanorods. A two-step hydrothermal method was used to prepare the samples. Some properties of the samples, such as morphological, structural, and optical properties were characterized by energy-dispersive X-ray detection, field emission scanning electron microscopy, X-ray diffraction, Raman spectroscopy, and ultraviolet-visible spectroscopy. Moreover, photoelectrochemical properties were studied via current-voltage and photocurrent spectrum measurements. The results showed that CdS nanorods grafted on top of TiO₂ nanorods like a lawn. The amount grafted as well as the diameter and crystallinity of CdS nanorods increased first and then decreased as the grafting time increased, due to Ostwald ripening. Under the back-side illumination, the composite film with 2 h grafting time exhibited the highest photocurrent density which was almost twice of that of the pure TiO₂ nanorods.