CdS及其稀土掺杂纳米带的制备与发光性质的研究

采用热蒸发法制备CdS及其稀土掺杂的纳米带(CdS∶Ce3+、CdS∶Er3+)。利用扫描电子显微镜(SEM)、X射线衍射仪(XRD)和荧光光谱仪(PL)对纳米带的形貌、晶体结构和发光性质进行了表征和分析。结果表明,所制备的纳米带的外形规则,表面光滑、平整,纳米带的厚度大约在20～60nm范围内;纳米带具有六方结构,晶格常数a=0.414nm、c=0.671nm;CdS纳米带的光致发光谱的谱峰位于405nm左右;CdS∶Ce3+纳米带的光致发光谱的谱峰位于523和535nm处;CdS∶Er3+纳米带的光致发光谱中观察到3个强的发光峰,分别位于525、556和582nm处。     

CdS Nanoscale Photodetectors

CdS nanostructures have received much attention in recent years as building blocks for optoelectronic devices due to their unique physical and chemical properties. This progress report provides an overview of recent research about rational design of CdS nanoscale photodetectors. Three kinds of photodetectors according to the metal‐semiconductor contact types are discussed in detail: Ohmic contact, Schottky contact, and field enhanced transistor configuration. The focus is on the tuning of optical and electrical properties CdS nanostructures by element doping, composition and bandgap engineering, and heterojunction integration, along with thus modified device performances generated during these tuning processes. Latest concepts of photodetector design such as flexible, self‐powered, plasmonic, and piezophototronic photodetectors with novel properties are introduced to demonstrate the future directions of such an exciting research field.     

Growth and photoluminescence of CdS and CdS:Mn Nanoribbons

CdS and CdS:Mn²⁺ Nanoribbons (NRs) are synthesized via a facile thermal evaporation approach. Their corresponding optical properties are investigated by room-temperature photoluminescence measurements. The spectrum of the undoped CdS NRs features four emission peaks: an intensive sharp one and three wide ones centered at 504 nm, 681 nm, 743 nm and 802 nm, respectively. The origins of them are discussed in detail. After doping with Mn²⁺ ions, only the host band-edge emission is retained, therefore, CdS:Mn²⁺ NRs present well narrow green band luminescence without any emission peaks from the Mn²⁺ ion. This property is quite meaningful for contributing in color light devices.     

Effect of heat-treatment on CdS and CdS/ZnS nanoparticles

Mono-dispersed and spherical cadmium sulfide (CdS) nanoparticles and cadmium sulfide/zinc sulfide (CdS/ZnS) nanoparticles, 4–5 nm in diameter, were synthesized in a heptane-AOT-water microemulsion system. The heat treatment of CdS and CdS/ZnS nanoparticles was annealed at 570 °C under the air atmosphere. The heat-treated nanoparticles were of variable large sizes and had enhanced crystallinity. UV–Vis spectra of heat-treated CdS and CdS/ZnS nanoparticles revealed a flat shape similar to that of bulk CdS compounds. The difference between the PL emission bands of organic-coated nanoparticles and heat-treated nanoparticles was small. The PL emission energy of heat-treated nanoparticles was improved by about 2–3 times compared with that of organic-coated nanoparticles.     

复合结构纳米晶CdS：Cu/CdS的制备及光学特性

在非配位溶剂中合成了高质量的CdS纳米晶核,并利用Cu2+离子对其进行掺杂,制备了CdS:Cu纳米晶.通过进一步采用连续离子层吸附反应的方法对CdS:Cu纳米晶进行表面修饰,得到CdS:Cu/CdS复合结构纳米晶.利用X射线衍射(XRD),透射电镜(TEM),紫外可见吸收光谱(UV-Vis)和荧光光谱(PL)对其结构、形貌以及光学性质进行了表征和分析,结果表明:所制备的复合结构CdS:Cu/CdS纳米晶为立方闪锌矿结构;与CdS纳米晶核相比,掺杂Cu2+可以使其表面态发光发生红移;在CdS:Cu纳米晶中,通过改变掺杂Cu2+的浓度,可以实现表面态发光在570和620nm之间的连续调节.与未经包覆的CdS:Cu纳米晶相比,包覆层CdS增强了纳米晶CdS:Cu的稳定性.     

Biomaterials supported CdS nanocrystals

CdS quantum dot materials were prepared through a simple room temperature deposition of CdS nanocrystals on biomaterials including starch and chitosan. Materials obtained were found to contain differently distributed CdS nanocrystals on the surface of the biopolymers, making them potentially interesting for biomedical applications as contrast agents and/or in photocatalysis.     

功能化CdS纳米晶的合成及CdS/聚苯乙烯纳米杂化材料的研究

以氯化镉和硫化钠为原料,采用巯基乙醇为有机配体,在H2O/DMF的溶剂中,制得分散均匀且表面富含羟基基团CdS纳米晶溶液.我们使用γ-甲基丙烯氧丙基三甲氧基硅烷(MPS)来修饰CdS纳米晶的表面,得到双键官能团化的CdS纳米晶.通过原位自由基聚合方法,成功地得到了聚苯乙烯基CdS纳米晶复合材料.利用傅里叶红外光谱仪(FT-IR)、透射电子显微镜(TEM)、紫外-可见光吸收光谱仪(UV-vis)、X射线衍射分析仪(XRD)、热重分析仪(TGA)、荧光光谱 (PL) 考察了CdS纳米晶及CdS/聚苯乙烯复合材料的结构和光学性能的关系规律.结果表明巯基乙醇表现出良好的光学性能,其配体不是简单的物理吸附于纳米晶表面,而是以化学键的形式和纳米晶表面镉原子相结合.相比于纯的聚苯乙烯材料,聚苯乙烯基CdS纳米晶材料表现出良好的光学和热学性能.     

Close-space sublimation grown CdS window layers for CdS/CdTe thin-film solar cells

We report on the synthesis and characterization of CdS window layers grown by close-space sublimation (CSS) method for CdS/CdTe thin-film solar cells. Comparing with CdS window layers grown by other methods such as sputtering and chemical bath deposition, CSS-grown CdS layers can facilitate the consumption of CdS layers and suppress the diffusion of Te into CdS window layers. CSS-grown CdS layers exhibit much larger grains with faceted morphology. Due to large grains, CSS CdS layers must be grown thick enough to minimize the effects of pin-holes. The use of thicker CdS layer causes reduced blue response, resulting in current loss. Therefore, the thickness of CSS CdS window layer must be carefully optimized to achieve high efficiency. Our best small area dot cell using a CSS CdS window layer has exhibited a cell efficiency of about 14.2 % with an open circuit voltage (V_OC) of 806 mV, a short circuit current (J_SC) of 25.2 mA/cm², and a fill factor (FF) of 69.8 % under AM1.5 illumination and without an antireflection coating, slightly lower than our best reference cell using a sputtered CdS window layer (V_OC = 845 mV, J_SC = 24.5 mA/cm², FF = 76.8 %, and efficiency = 15.8 %).     

CdS纳米粒子的制备方法

CdS纳米粒子是一种十分重要的光电功能材料 ,具有十分重要的应用价值 ,本文对Cds纳米粒子的各种制备方法进行了总结 ,并对各种方法进行了评述     

功能化CdS纳米晶的制备

以氯化镉和硫化钠为原料,2-巯基乙醇(ME)为有机配体,成功制备了粒径可控的、表面富有羟基的CdS纳米晶.采用不同的ME/Cd2 及H2O/DMF比例以观察有机配体及溶剂对生成粒子尺寸的影响.透射电子显微图证实了球形CdS纳米粒子很好地分散在H2O/DMF溶液中,没有任何团聚现象发生.傅立叶变换红外谱图(FT-IR)显示了羟基基团成功地包覆在纳米晶的表面.X线衍射(XRD)测试揭示了功能化CdS纳米晶的晶形主要为立方晶.     

Solvothermal route to CdS nanocrystals

We developed a facile solvothermal route to various CdS nanocrystals in diethylenetriamine. Well-crystalline CdS nanowires and flower-like CdS nanocrystals were obtained at temperatures 220°C and 200°C, respectively. The nanowires have smooth surfaces and are grown along polar [0?0?0?1] direction. The flower-like CdS nanocrystals have hierarchical architectures composed of fine nanowires with lengths up to 10?µm. The effects of temperature on the morphology and structure of the final products are also investigated. The experimental observations indicates that high temperature facilitates fabricate CdS nanocrystals with regular morphology and excellent crystallisation. Moreover, it is found that organic solvent diethylenetriamine plays an important role in the growth of CdS nanocrystals. Diethylenetriamine can bind Cd²⁺ ions to form intermediate complex, resulting in final CdS nanocrystals with regular morphologies.     

Investigation of structural and optical properties of the CdS and CdS/PPy nanowires

In this study, cadmium sulfide (CdS), polypyrrole (PPy) nanowires, and their heterojunctions have been electrochemically synthesized. Morphology of the nanowires has been investigated by scanning electron microscopy. Energy dispersed X-ray, X-ray diffraction, UV–Vis, and FTIR analyses have been used to confirm structure of both CdS and PPy nanowires. For the first time with this study, CdS/PPy nanowire heterojunctions have been integrated into photoelectrochemical (PEC) cells. It has been also demonstrated that PEC performance of the nanowires was strongly function of production conditions, such as deposition time and voltage. The maximum power conversion efficiency of the CdS nanowires obtained in this study was 1.36%. Moreover, efficiencies of the CdS/PPy nanowires have been reached to 5.00%, which makes them very favorable for PEC applications.     

Microstructures of electrodeposited CdS layers

Cadmium sulfide (CdS) thin films were electrodeposited on two conducting oxide substrates from aqueous solutions at temperatures between 30 and 90 °C. The as-deposited films were characterized using scanning electron microscopy, transmission electron diffraction, atomic force microscopy and Raman spectroscopy and were found to be crystalline at all temperatures. The microstructural development of the films is also discussed based on field emission scanning electron microscopy and atomic force microscopy studies. The composition of the films was found to be independent of the deposition temperature, with a slight difference in the Cd/S ratio on the different substrates.     

Luminescence in Mn-doped CdS nanocrystals

We have synthesized Mn-doped CdS nanocrystals (NCs) with size ranging from 1.8–3 nm. Photoluminescence (PL) spectra of the doped NCs differ from that of the undoped NCs with an additional peak due to Mn d-d transitions. Electron paramagnetic resonance spectra along with X-ray absorption spectroscopy and PL spectra confirm the incorporation of Mn in the CdS lattice. The fact that emissions from surface states and the Mn d levels occur at two different energies, allowed us to study the PL lifetime decay behaviour of both kinds of emissions.     

CdS纳米粒子的制备方法

CdS纳米粒子作为一种十分重要的光电功能材料，近年来引起人们的广泛关注，各种各样的制备方法也由此应运而生。因制备方法不同，所得CdS纳米粒子的粒径、粒度均匀性、纯度及相结构等也各不相同，并进而会对它们的属性（如光电性质）产生很大的影响。如何以材料的形式付诸应用，依据功能的需求，实现对半导体纳米粒子的粒径、形状、粒度均匀性分布以及纯度等的控制是目前CdS纳米粒子制备方法的发展方向。     

CdS空心微球的制备与表征

以不同粒径的苯乙烯-丙稀酸(酯)共聚物(PSA)乳胶粒为模板,制备出均匀的PSA/CdS核壳复合结构的微球,用有机溶剂溶去模板PSA后,分别制备了不同粒径的CdS空心微球.透射电镜分析结果表明,以直径250、340和600nm的PSA乳胶粒为模板,所得CdS空心球的粒径均匀,直径分别为340、450和800nm.紫外可见吸收光谱显示3个CdS空心球样品的最大吸收分别为480nm、410nm和485nm.     

CdS纳米线阵列光致发光的研究

用直流电沉积法在多孔氧化铝模板中制备了高度有序的CdS纳米线阵列,SEM和XRD的观察和测量表明,CdS纳米线尺寸均匀、排列规整,具有六方纤锌矿结构,Cd和S的化学计量比为11.CdS纳米线阵列的光致发光测量显示,激发波长为325nm时,CdS纳米线阵列在450nm处有一强的PL峰,在484nm处还有一肩峰.对其光致发光机理进行了分析.     

硫化镉纳米粒子的制备

探索纳米硫化镉的制备方法,对纳米晶体形成机理、结构性能进行基础研究;分析了影响溶胶团簇性质的因素,包括体系温度、稳定剂比例、pH值和反应物用量.结果显示利用六偏磷酸钠为稳定剂,氯化镉和硫化钠为反应物在水相中反应可以制得稳定的硫化镉纳米溶胶团簇.