CdS/CuInS_2/TiO_2复合纳米薄膜光电性能的研究

利用连续离子层吸附反应(SILAR)法在Ti O2纳米棒阵列表面沉积生长了Cu In S2和Cd S量子点,采用FESEM表征了复合纳米薄膜的结构和形貌,采用紫外可见分光光度计和电化学工作站表征了薄膜的光学和光电性能。当Cu In S2和Cd S薄膜循环沉积次数均为5次时,薄膜的光电响应最强,光电响应程长为20μA/cm2。     

沉积次数对CdS/TiO_2复合纳米薄膜光电性能的影响

采用水热法在FTO导电玻璃基底表面制备了结构规整的TiO2纳米棒阵列,利用连续离子层吸附反应(SILAR)法在TiO2纳米棒阵列表面沉积生长了CdS量子点,采用紫外可见分光光度计和电化学工作站表征了薄膜的光学和光电性能,随着CdS循环次数的增加,薄膜的光电响应越明显,当CdS循环沉积次数为9次时,薄膜的光电响应程长约为514μA/cm2。     

以矿粉制备纳米吸附剂及其吸附性能研究

铅离子由于会富集在生物体重要器官,造成严重的生物毒性。本文以矿渣为原料采用共沉淀法制备纳米羟基磷灰石(HA)颗粒。结果表明:合成的低结晶度的HA纳米颗粒呈现球形,粒径分布在50~80 nm。纳米HA对铅离子具有良好的吸附性能,其吸附机制为溶解-沉积反应。纳米HA置于铅离子溶液后发生溶解反应,释放出的磷酸根离子与溶液中的铅离子反应生成棒状铅磷灰石(Pb HA)。纳米HA颗粒对铅离子吸附性能的影响因素包括溶液铅离子浓度、溶液p H值和吸附温度。铅离子浓度越高、p H值越小、吸附温度越高,则纳米HA对铅离子的平衡吸附量越高。因此,纳米HA在吸附重金属铅离子领域具有重要的应用前景。     

连续离子层吸附反应法制备(Zn,Cd)S薄膜及其性能

采用液相薄膜制备工艺——连续离子层吸附反应法(successive ionic layer adsorption and reaction,SILAR),在室温下,使用混合阳离子前驱体于玻璃衬底上制备了(Zn,Cd)S薄膜．采用X射线光电子谱分析薄膜的成分,测定紫外透射光谱,分析不同成分对薄膜光电性能的影响,并使用环境扫描电镜对薄膜的表面形貌进行观察．实验结果表明：SILAR法制备薄膜的生长速率约为3nm／cycle。(Zn,Cd)S薄膜的成分偏离前驱体溶液中的n(Zn)／n(Cd)值,表现为Cd含量偏大,这与CdS和ZnS二者的溶度积不同有关。随着Cd含量的增加,薄膜的透射率和禁带宽度降低,电导率增大。通过控制前驱体混合溶液中不同阳离子间的比例可以得到带宽可调的复合硫化物薄膜。     

均匀沉淀法制备不同粒径的纳米Cu（OH）2

以无水硫酸铜和氢氧化钡为原料,采用均匀沉淀法研究了不同粒径纳米Cu（OH）2的制备,考察了搅拌温度、硫酸铜溶液浓度等反应条件对纳米Cu（OH）2粒径的影响。实验结果表明,用均匀沉淀法可以制备出不同粒度的纳米Cu（OH）2颗粒。反应条件对纳米Cu（OH）2的粒径有显著影响,反应温度越高,纳米粒子的粒径越小;硫酸铜溶液的浓度越高,纳米粒子的粒径越大。     

n型氧化亚铜薄膜的制备及其光电化学特性

采用三电极系统在硫酸铜-乳酸体系中电化学沉积法制备Cu2O薄膜,控制电沉积溶液的温度和pH得到n型Cu2O薄膜,并通过光电流(I-t)测试、莫特-肖特基(M-s)曲线测试薄膜的光电性能。结果表明当pH值为8.5～10时,成功地制备出了n型Cu2O薄膜,且当电解液的pH值为8.5,温度为60℃时,n型Cu2O薄膜光电性能最佳。对Cu2O薄膜进行退火处理,有助于改善氧化亚铜薄膜的光电性能。在此基础上,我们对n型Cu2O薄膜进行不同离子掺杂。离子的掺杂能继续提高Cu2O薄膜的光电性能。其中当Cl-为40 mM条件下,Cu2O薄膜的光电化学性能最佳。     

磺酸基功能化磁性纳米粒子的制备、表征及除去水中Cu(Ⅱ)的研究

通过化学一步共沉淀法制备了疏水性的Fe3O4纳米粒子,然后采用反相微乳液法制备出分散性良好、粒径均匀的Fe3O4@SiO2复合磁性纳米粒子,紧接着用2-(4-氯磺酰苯基)乙基三甲氧基硅烷对其表面进行修饰,最终再经过1.0 MNaCl溶液处理得到富含磺酸基官能团磁性纳米吸附剂(Fe3O4@SiO2-SO3Na)。通过透射电镜(TEM)、X射线衍射(XRD)、红外光谱(FT-IR)、振动样品磁强计(VSM)等对其进行了表征,着重研究了其对水溶液中Cu(Ⅱ)离子的吸附性能。结果表明,溶液的pH值能显著影响吸附剂对Cu(Ⅱ)离子的吸附效果,其中pH值为5.1时吸附效果最佳,即Cu(Ⅱ)从初始的20mg.L-1降低至0.45mg.L-1,意味着97.8%的Cu(Ⅱ)从溶液中除去,通过用0.1M HCl洗涤可把Cu(Ⅱ)从吸附剂中脱离下来并且可以重复使用。     

Sodium sulfonate functionalized magnetic Fe3O4@SiO2 towards the preparation of sorbent for Cu(Ⅱ) removal

通过化学一步共沉淀法制备了疏水性的Fe3O4纳米粒子,然后采用反相微乳液法制备出分散性良好、粒径均匀的Fe3O4@SiO2复合磁性纳米粒子,紧接着用2-(4-氯磺酰苯基)乙基三甲氧基硅烷对其表面进行修饰,最终再经过1.0 M NaCl溶液处理得到富含磺酸基官能团磁性纳米吸附剂(Fe3O4@SiO2-SO3Na).通过透射电镜(TEM)、X射线衍射(XRD)、红外光谱(FT-IR)、振动样品磁强计(VSM)等对其进行了表征,着重研究了其对水溶液中Cu(Ⅱ)离子的吸附性能.结果表明,溶液的pH值能显著影响吸附剂对Cu(Ⅱ)离子的吸附效果,其中pH值为5.1时吸附效果最佳,即Cu(Ⅱ)从初始的20mg·L-1降低至0.45mg·L-1,意味着97.8％的Cu(Ⅱ)从溶液中除去,通过用0.1M HCl洗涤可把Cu(Ⅱ)从吸附剂中脱离下来并且可以重复使用.     

三维In_2S_3/TiO_2纳米复合材料的制备及光电性能

采用阳极氧化法在钛网基底上制备出TiO_2纳米管阵列,利用连续离子层吸附法(SILAR)将半导体In_2S_3沉积到TiO_2纳米管表面,制备In_2S_3/TiO_2纳米复合材料。利用扫描电子显微镜(SEM)、X-射线衍射仪(XRD)及紫外-可见漫反射光谱(DRS)对材料的形貌和结构进行表征,并通过荧光光谱仪以及光电信号对不同沉积圈数的In_2S_3/TiO_2纳米复合材料的光电性能进行测试。结果表明,制备的In_2S_3纳米颗粒均匀沉积在TiO_2纳米管上,并且不会堵塞纳米管的管孔。沉积不同圈数的In_2S_3/TiO_2纳米复合材料表现出不同的光电化学性质。     

Ti和NiTi表面Ni–Ti–O纳米层的显微结构及电催化性能

采用水热合成法在钛片和镍钛片表面制备了多种形貌的Ni–Ti–O纳米层。采用扫描电镜(SEM)和透射电镜(TEM)观察Ni–Ti–O纳米层的微观形貌。用循环伏安法初步研究了Ni–Ti–O纳米层对甲醇的催化氧化能力。结果表明:水热合成过程中溶液的Ti/Ni浓度比和基体材料种类对产物的微观形貌有重要影响。随着溶液中镍浓度的升高,纯Ti片上纳米层颗粒逐渐变小,分布变得均匀;NiTi片表面的纳米层则从纳米线束状结构转变为Ni–Ti–O纳米片结构。当溶液中无TiCl_4时,Ti片表面的产物为垂直于其生长的纳米薄片。与纯钛片相比,以镍钛合金片作为基体制备的电极对甲醇的电催化性能更好。     

Effect of post-deposition annealing on the properties of ZnO films obtained by high temperature,micro-controller based SILAR deposition

The ZnO thin films were prepared by successive ionic layer adsorption and reaction (SILAR) method at elevated precursor temperature. The films were later subjected to post-deposition annealing at different temperatures. This annealing process was found to be beneficial as it improved the structural and optical properties of the films. The ZnO films obtained by SILAR were found to be polycrystalline with hexagonal crystal structure. The crystallite size of the films increased considerably after annealing. The annealed films also showed very high absorption in UV region with marginal change in band gap. Both the crystallite size and optical absorbance were found to increase proportionately with the annealing temperature.     

Boosting the Performance of ZnO/CdS Core-Shell Nanorod Array-based Solar Cells by ZnS Surface Treatment

With a view to enhancing the efficiency of ZnO/CdS core-shell nanorod array-based semiconductor sensitized solar cells (SSSCs), ZnS surface treatment is envisioned. It is achieved through a thin layer of ZnS being deposited onto ZnO/CdS film by a successive ionic layer adsorption and reaction (SILAR) technique. To ascertain the optimum thickness of ZnS and to enhance the solar cell performance, we have varied the number of SILAR cycles of ZnS deposition. The optimized film is then considered for structural, morphological, and electrochemical studies. The analysis reveals the benefits of ZnS surface treatment on ZnO/CdS core-shell photoelectrodes in terms of an enhancement of solar cell performance of up to 1.54 % from 1.23 %.     

Effect of Cu2O thin film on Cu–Sn alloy coated steel surface in promoting interfacial adhesion with rubber

In the present study, effect of Cu₂O film deposited via successive ionic layer adsorption and corresponding chemical reaction (SILAR method) on Cu–Sn coated steel substrate was explored for the purpose of improving the adhesion of steel with rubber. The effect of the relative alkali concentration in the oxide film deposition bath and the number of immersion cycles on the interfacial adhesion affecting the nature of oxide film deposited, its thickness and surface coverage were investigated. In the current study, Cu–Sn coated steel bead wire with coated surface roughness (R_a) around 2 μm showed an improvement of 33% in adhesion (in terms of pull out force) with an optimum alkali/Cu ion concentration of 25:1 with single dipping cycle attributed to an optimum oxide coating thickness of ~70 nm. Surface morphology study exhibited formation of thicker coating with increase in number of dipping cycles. Satisfactory thermal stability of the Cu₂O film was confirmed as no re-oxidation of the Cu₂O film to CuO was observed in the 200 °C heat treated samples.     

α-Al2O3载体上b-轴取向MFI分子筛膜的制备

在α-Al2O3支撑的PVA表面手工组装紧密排列的b-轴取向silicalite-1分子筛晶体层,煅烧除去高聚物层后可得到很好的晶种层。采用两步法二次合成工艺,在多孔氧化铝载体表面可直接合成完备的b-轴取向MFI型分子筛膜。n（TEOS）：n（TPAOH）：n（H20）为1．0：0．2：200．0的合成液经150℃预加热处理可有效减少二次生长过程中α-轴孪晶的生成,保证制备的MFI膜为很好的b-轴取向。SEM及XRD检测表明所制备膜层的完备性及b-轴取向。另外采用多层取向晶种层经过一次晶化3h即可制备完备的b-轴取向多层MFI型分子筛膜。实现了在大孔载体上直接合成b-轴取向的MFI膜,对提高膜的应用性能有重要意义。     

超临界浸渍法制备CuO/Al_2O_3催化剂

应用超临界浸渍法制备CuO/γ-Al2O3催化剂。以Cu(NO3)2为前驱体,甲醇为助溶剂在载体Al2O3上于超临界二氧化碳中进行浸渍,研究了不同浸渍条件:超临界温度、压力、浸渍时间、前驱体和载体量之比,助溶剂量等因素对浸渍效果的影响。并以SEM和XRD分别对超临界与普通浸渍法制备的样品进行了表征。结果说明,超临界浸渍时吸附速度明显较快,吸附量大,浸渍物分布均匀且和载体作用较强。以亚甲基蓝的催化氧化降解为模型反应测定两种制法催化剂的活性,超临界条件制备的催化剂活性明显较好。所得结果表明,使用无机金属前驱体加助溶剂的方法可以代替有机金属前躯体在超临界浸渍中的使用。     

The effect of chelating reagents on the layer-by-layer formation of CdS films in the electroless and electrochemical deposition processes

Triethanolamine (TEOA) and cysteine (Cys) were examined for the effect of chelating reagents to deposit CdS thin films by means of two different processes. Those are the successive ionic layer adsorption and reaction (SILAR) method and the successive under potential deposition (UPD) method, in which Cd and S are separately deposited on a polycrystalline Au substrate from each solution. Evaluation by stripping voltammetry showed that the amount of the deposited CdS was increased for 1, 3, 5, 7 and 10 layers of CdS prepared by these methods. It was found that, with the SILAR method, the order of the ability to increase CdS deposition was Cys>TEOA>none. On the other hand, with the successive UPD method, the order was none≥TEOA>Cys, showing a certain inhibition in the electrochemical deposition process. It is concluded that CdS deposition by the SILAR method becomes compatible to the successive UPD when a suitable chelating reagent was added to the Cd solution.     

Flexible TiO2 nanograss array film decorated with BiOI nanoflakes and its greatly boosted photocatalytic activity

A flexible TiO₂ nanograss array film on Ti wire mesh was prepared by a mild chemical reaction. To overcome its shortcoming of almost no absorption of visible light, successive ionic layer adsorption and reaction (SILAR) was executed to decorate the prepared TiO₂ film with BiOI. The results of XRD and SEM measurements showed that BiOI nanoflakes formed on the surface of TiO₂ film, and the loading amounts of BiOI nanoflakes increased with the increase in SILAR cycles. The XPS results confirmed the heterojunction formation of BiOI-TiO₂. The photocurrent measurement suggests that a moderate loading amount of BiOI nanoflakes is beneficial to improve the charge separation efficiency, which is ascribed to the heterojunction formation of BiOI-TiO₂. The BiOI-decorated TiO₂ film with SILAR cycles of seven showed the most excellent visible-light photocatalytic activity among all the samples. Compared with the bareTiO₂ nanograss array film, its visible-light photocatalytic activity increased by 11.7 times. The flexible BiOI-decorated TiO₂ nanograss array film with high photocatalytic activity shows great applications in air pollution and the pollution caused by offshore oil spills.     

Investigation of multilayered quantum dot-sensitized solar cells with different Zn chalcogenide passivation layers

In the case of cadmium sulfide (CdS) and cadmium selenide (CdSe)-based quantum dot-sensitized solar cells (QDSSCs), the addition of a zinc sulfide (ZnS) passivation layer improves the solar cell performance. In this study, multilayered QDSSCs were fabricated using CdS and CdSe quantum dots prepared by successive ionic layer adsorption and reaction (SILAR) method. The optimized QDSSCs were used to study the passivation effect of zinc chalcogenide layers: ZnS, zinc selenide (ZnSe), and zinc telluride (ZnTe). The best performing solar cell prepared from four SILAR cycles of CdS followed by six SILAR cycles of CdSe were used for subsequent deposition of Zn chalcogenide layers. It was observed that capping with ZnSe or ZnTe layer on the multilayered Cd chalcogenide QDs did not improve the solar cell performance. Only the addition of ZnS layer contributed to the better performance of the solar cell. The efficiency obtained in the optimized multilayered CdS/CdSe QDSSC with ZnS layer was 1.37 %, while the QDSSC with ZnSe or ZnTe capping showed lower performance. The behavior of the solar cells is explained with electrochemical impedance spectroscopy study.     

Solid-state dye-sensitized ZnO solar cells prepared by low-temperature methods

Solid-state dye-sensitized solar cells based on highly porous ZnO films prepared by template-assisted electrodeposition as electron collector, the indoline dye D149 as sensitizer and CuSCN as hole collector have been prepared using three different methods, namely impregnation with saturated CuSCN solution, successive ionic layer adsorption and reaction (SILAR) and electrodeposition, for filling the pores in the ZnO with CuSCN. The highest pore filling and the highest conversion efficiency of 0.46% were achieved with the impregnation method, while SILAR led to a very low pore filling, causing very low photocurrents, and electrodeposition led to short-circuiting between the CuSCN and the conducting substrate of the ZnO sample despite the presence of a compact ZnO bottom layer between the porous ZnO layer and the conducting layer, causing very low open-circuit voltages.