Investigation of Cu(In,Ga)Se2/In2S3 diffuse interface by Raman scattering

The CIGSe/In₂S₃ interface is known to be highly diffuse because of the migration of Cu from the CIGSe into the In₂S₃. Most of the analytical techniques allowing the determination of composition profiles throughout this interface involve ion etching either during the samples preparation or during data acquisitions. In the present work, we have explored the potential of the Raman scattering for the characterization of such interfaces. This technique is non destructive and provides information on both the composition and the structure of the materials that are probed. Three CIGSe/In₂S₃ structures have been investigated; the parameter varying being the substrate temperature during the In₂S₃ deposition. For the first time we could demonstrate that at high temperature, the CuInS₂ Cu-Au phase is formed at the CIGSe/In₂S₃ interface. Furthermore, the thickness of the ordered defect compound at the CIGSe surface increases with the deposition temperature. All of the new knowledge collected during this work shows the relevance of using the Raman scattering technique for the characterization of the CIGSe/In₂S₃ interface.     

Investigation on solar photocatalytic activity of TiO2 loaded composite: TiO2/Eggshell, TiO2/Clamshell and TiO2/CaCO3

The TiO₂/Eggshell, TiO₂/Clamshell and TiO₂/CaCO₃ loaded composites were prepared by sol-gel method and characterized by XRD and SEM. Their photocatalytic activities were measured through the degradation of Acid Red B under solar light irradiation. The influences of TiO₂ loaded content, heat-treated temperature and time on the photocatalytic activities were reviewed. The effects of irradiation time and dye initial concentration on the photocatalytic degradation were also investigated. The results showed that the photocatalytic activity can be greatly enhanced by appropriate TiO₂ loaded content.     

Preparation and characterization of N–I co-doped nanocrystal anatase TiO2 with enhanced photocatalytic activity under visible-light irradiation

N–I co-doped TiO₂ nanoparticles were prepared by hydrolysis method, using ammonia and iodic acid as the doping sources and Ti(OBu)₄ as the titanium source. The prepared catalysts were characterized by X-ray diffraction (XRD), transmission electron microscopy (TEM), X-ray photoelectron spectroscopy (XPS), Fourier transform infrared spectroscopy (FTIR) and ultraviolet–visible diffuse reflection spectroscopy (UV–vis DRS). XRD spectra show that N–I–TiO₂ samples calcined at 673 K for 3 h are of anatase structure. XPS analysis of N–I–TiO₂samples indicates that some N atoms replace O atoms in TiO₂ lattice, and I exist in I⁷⁺, I⁻ and I⁵⁺ chemical states in the samples. UV–vis DRS results reveal that N–I–TiO₂ had significant optical absorption in the region of 400–600 nm. The photocatalytic activity of catalysts was evaluated by monitoring the photocatalytic degradation of methyl orange (MO). Compared with P25 and mono-doped TiO₂, N–I–TiO₂ powder shows higher photocatalytic activity under both visible-light (λ > 420 nm) and UV–vis light irradiation. Furthermore, N–I–TiO₂ also displays higher COD removal rate under UV–vis light irradiation.     

Pt纳米颗粒负载SrTiO3/TiO2异质结结构制备及制氢性能

本文以固定n(Sr)/n(Ti)摩尔比0.4的SrTiO_3/TiO_2(金红石相)异质结纳米颗粒,通过"光催化还原沉积方法"制备不同质量分数的纳米铂颗粒(0、1%、2%、5%),探究其催化活性的变化,采用XRD、SEM、UV-vis、XPS方法对其进行表征,并做了相关光催化分解水产氢性能测试.结果表明:负载贵金属Pt纳米颗粒量越大,对应的Pt晶粒平均尺寸为40.8 nm,1%Pt纳米颗粒SrTiO_3/TiO_2异质结构的BET比表面积在23.195 m~2/g处最高,并且介孔材料的特征是平均Barrett-Joyner-Halenda(BJH)孔径为13.60 nm,总孔体积为0.079 cm~3/g;高BET表面积和大的总孔体积强烈地支持SrTiO_3/TiO_2具有介孔结构的事实;相应的催化剂催化活性越高,其中负载5%Pt纳米颗粒的SrTiO_3/TiO_2纳米颗粒光催化8 h产氢量为3.574 mmol,平均产氢效率为0.447 mmol/(gcat·h),但从性价比的角度来考虑,其催化效率远不及负载1%Pt纳米颗粒的SrTiO_3/TiO_2纳米颗粒催化效率的5倍,因此负载5%Pt的SrTiO_3/TiO_2纳米颗粒光催化效率最高.     

Comparative study of In2S3-ITO bilayers deposited on glass and different plastic substrates

In this work ITO thin films have been grown onto glass, polyethylene terephthalate (PET) and Arylite polymer substrates by sputtering at room temperature.The In₂S₃ films were chemically deposited on ITO during different times, forming bilayers for subsequent photovoltaic applications. Optical properties of the films were investigated from the transmittance and the structural properties by XRD. Transmittance of the films varies with deposition time and the different substrates used, the same as the adherence and the homogeneity of the films.     

玄武岩纤维/TiO2复合材料的制备及表征

TiO_2纳米粉体应用于光催化领域存在光吸收仅局限于紫外光区域、难以回收等缺点,因此,纳米TiO_2固定化和可见光改性成为光催化领域的两个研究热点.本文采用绿色环保的水热法,将TiO_2负载于玄武岩纤维载体上,在较低的温度下制备出一种新型的玄武岩纤维/TiO_2复合材料.使用XRD分析了复合材料的物相结构,采用SEM观测了复合材料的形貌,并对水热法合成其机理进行了分析.结果表明:150℃水热条件下、反应10 h合成的玄武岩纤维/TiO_2复合材料中,颗粒状的TiO_2涂层均匀包覆于玄武岩纤维表面,并没有改变玄武岩纤维结构,形成了一种具有核壳结构的新型玄武岩纤维/TiO_2复合材料,经过TiO_2修饰的玄武岩纤维对可见光有很好吸收.因此,玄武岩纤维/TiO_2复合材料是一种具有潜在应用价值的可见光催化材料.     

The reaction mechanism of the spray Ion Layer Gas Reaction process to deposit In2S3 thin films

The spray Ion Layer Gas Reaction (ILGAR) is a well-established, patented and commercial process used primarily to deposit In₂S₃ as buffer layers in thin film solar cells. In this paper we investigate the growth mechanism of the spray In₂S₃ ILGAR process by characterising the intermediate growth stages of films, following the growth mechanism with a quartz crystal microbalance and tracking the gaseous side-and-intermediate products during film growth, using a mass spectrometer. A basic growth mechanism model is then proposed based on an aerosol assisted chemical vapour deposition of an In(O_x,Cl_y,(OH)_z) film, as the first stage process, followed by the conversion of the intermediate film using H₂S gas to In₂S₃.     

Preparation and photoelectrochemical performance of TiO2/HS-CH2-COOH/Cu3Se2 composite film

In this paper, the TiO₂/HS-CH₂-COOH/Cu₃Se₂ composite film photoanodes were fabricated on conducting glass plates. Cu₃Se₂ nanoparticles were used as the sensitizer and the bi-functional modifier HS-CH₂-COOH was used at the interface between Cu₃Se₂ and TiO₂ films to improve the properties of the film photoanode. The characterization results show that the sol-gel prepared anatase TiO₂ film has a compact and uniform surface, while the tetragonal Cu₃Se₂ film has a coarse surface which is made up of uniform elongated particles. The photoelectrochemical experimental results indicate that the TiO₂/HS-CH₂-COOH/Cu₃Se₂ composite film photoanodes have a good photovoltaic property.     

Influence of sodium compounds at the Cu(In,Ga)Se2/(PVD)In2S3 interface on solar cell properties

The present contribution deals with indium sulfide buffer layers grown by thermal co-evaporation of elemental indium and sulfur. It has been found necessary to deposit these buffer layers at low substrate temperatures in order to reach V_oc values similar to those with (CBD)CdS. However, such deposition conditions lead to the formation of a highly recombinative Cu(In,Ga)Se₂/indium sulfide interface. This behaviour may be associated to the presence of sodium carbonates/oxides at the interface even though the Cu(In,Ga)Se₂ surface was cleaned in NH₃ (1 M, room temperature) prior to the indium sulfide deposition. An explanation is that, despite the chemical etch, sodium carbonates/oxides remain in the air exposed Cu(In,Ga)Se₂ grain boundaries and can migrate towards the surface when the Cu(In,Ga)Se₂ is heated under vacuum. These polluted interface areas act as recombination zones and thus inferior devices. A possibility to improve the device performance (i.e. improve the interface quality) is to sulfurize the remaining sodium carbonates/oxides. The resulting Na₂S can then leave the interface by formation of a solid solution with the indium sulfide. By adapting the buffer layer deposition process, 13.3% efficiency devices with co-evaporated indium sulfide are realized, performance which is close to that reached with (CBD)CdS.     

Preparation and photocatalytic activity of anatase TiO2 nanocrystallites with high thermal stability

Anatase TiO₂ nanocrystallites were prepared from TiCl₄ with addition of aqueous ammonia by changing Ti(OH)₄ hydrogel into its corresponding alcogel followed by supercritical drying in ethanol medium. The as-prepared TiO₂ was characterized by XRD, TG and BET. The results show that the prepared anatase TiO₂ has remarkable high thermal stability. The anatase structure of the prepared TiO₂ is maintained even after calcination up to temperatures as high as 800 °C. The photocatalytic activity of the prepared TiO₂ calcined at 800 °C in degradation of reactive brilliant red X-3B is comparable to commercially available nanosized P25 TiO₂.     

Visible-light photocatalysis in nitrogen-carbon-doped TiO2 films obtained by heating TiO2 gel-film in an ionized N2 gas

To use solar irradiation or interior lighting efficiently, we sought a photocatalyst with high reactivity under visible light. Nitrogen and carbon doping TiO₂ films were obtained by heating a TiO₂ gel in an ionized N₂ gas. The as-synthesized TiO_2−x−yN_xC_y films have shown an improvement over titanium dioxide in optical absorption and photocatalytic activity such as photodegradation of methyl orange under visible light. The process of the oxygen atom substituted by nitrogen and carbon was discussed. Oxygen vacancy induced by the formation of Ti³⁺ species and nitrogen and carbon doped into substitution sites of TiO₂ have been proven to be indispensable for the enhance of photocatalytic activity, as assessed by UV-Vis Spectroscopy and X-ray photoemission spectroscopy.     

Controlled synthesis and photocatalytic properties of porous hollow In2O3 microcubes with different sizes

Uniform single-crystalline In(OH)₃ hollow microcubes have been synthesized in large quantities via a hydrothermal reaction of InCl₃ with NaF and ethylene glycol (EG) at 140–220 °C for 12 h. Porous In₂O₃ hollow microcubes with a polycrystalline cubic structure can be obtained via calcining In(OH)₃ precursors at 400 °C for 2 h in air. Controlled Synthesis of In(OH)₃ and In₂O₃ hollow microcubes with the average edge lengths in the range of 2.0–4.7 μm can be achieved by changing the hydrothermal reaction temperature. The In(OH)₃ hollow microcubes were formed via an EG-assisted oriented attachment growth route using HF bubbles as the templates. Photocatalytic activities of the as-synthesized porous In₂O₃ hollow microcubes were studied at room temperature. The results indicated that the hollow In₂O₃ nanostructures display high photocatalytic activity in the photodegradation of rhodamine B and methyl orange.     

Preparation of rod-like Sb2S3 dendrites processed in conventional hydrothermal

Large-scale rod-like antimony sulfide (Sb₂S₃) dendrites have been prepared by hydrothermal method using antimony chloride (SbCl₃), citric acid and thioacetamide as raw materials at 160 °C for 12 h. The powder X-ray diffraction pattern shows the Sb₂S₃ crystals belong to the orthorhombic phase with calculated lattice parameters a = 1.120 nm, b = 1.128 nm and c = 0.3830 nm. The quantification of energy dispersive X-ray spectrometry analysis peaks gives an atomic ratio of 2:3 for Sb:S. Transmission electron microscopy micrograph studies reveal the appearance of the as-prepared Sb₂S₃ is dendrites-like which is composed of nanorods with the typical width of 300-500 nm and length of 5-20 µm. Finally the influences of the reaction conditions are discussed and a possible mechanism for the formation of rod-like Sb₂S₃ dendrites is proposed.     

等离子体电解氧化法制备多孔TiO2/V2O5复合物膜层及其增强光催化产氢活性

较差的光催化产氢效率极大地阻碍了TiO₂光催化剂的工业化应用。为此,本文在含有NH₄VO₃的磷酸盐溶液中,采用等离子体电解氧化(PEO)法制备了多孔TiO₂/V₂O₅复合膜光催化剂,通过扫描电子显微镜(SEM)、能谱仪(EDS)、X射线衍射(XRD)、X射线光电子谱(XPS)和紫外可见漫反射光谱(UV-Vis DRS)对其组成、结构及光吸收性质进行了表征,并采用气相色谱评价了薄膜催化剂的光催化产氢性能,研究了电解液中NH₄VO₃含量对膜的结构、组成和光催化产氢性能的影响。结果表明:复合膜催化剂主要由锐钛矿和金红石型TiO₂组成,具有微孔结构,V₂O₅主要以无定形形式存在于膜中,与TiO₂有很强的相互作用,影响TiO₂的晶面间距。研究发现,元素V抑制了TiO₂的结晶和金红石型TiO₂的形成,扩大了薄膜的光学吸收范围。针对Na₂S+ Na₂SO₃溶液中的光催化产氢性能的研究显示,在质量浓度为1 g/L NH₄VO₃的电解液中制备的TiO₂/V₂O₅薄膜的光催化活性最高,优于近年来报道的其他光催化剂。光催化重复实验表明,该复合膜催化剂具有较高的稳定性和较为恒定的光催化活性。     

Fabrication of photocatalytic heat-mirror with TiO2/TiN/TiO2 stacked layers

The photocatalytic heat-mirror based on TiO₂/TiN/TiO₂ stacked layers is prepared by reactive magnetron sputtering on quartz substrates under substrate-heating condition. We find that the addition of a thin Ti interlayer between the TiN and the outer TiO₂ layers drastically improves the heat-insulating performance. This type of stacked layer also exhibits higher photocatalytic activity for decomposition of acetaldehyde gas, compared with a TiO₂ single layer. The optical property of the TiN in TiO₂/TiN/TiO₂ stacked layers is the key not only revealing excellent heat-insulating effect but also improving the photocatalytic performance of the outer TiO₂ layers in the stacked layers.     

Nanoscale ZnS/TiO2 composites: Preparation, characterization, and visible-light photocatalytic activity

Photoactive ZnS/TiO₂ nanocomposites were prepared via microemulsion-mediated solvothermal method. The structure, composition, physicochemical property, and morphology of the composites were characterized by powder X-ray diffraction (XRD), Raman scattering studies, UV diffuse reflectance spectroscopy (UV/DRS), photoluminescence (PL) spectroscopy, and transmission electron microscopy (TEM). It showed that the composites were cube-shaped with particle sizes of 10 to 15 nm, and the phase structure for ZnS and TiO₂ in the composites was cubic and anatase, respectively. The content of the ZnS in the composites was 2.1%, 10.7%, and 19.9%, respectively. Compared with the solitary anatase TiO₂, the ZnS/TiO₂ exhibited enhanced visible-light photocatalytic activity for the aqueous parathion-methyl degradation. Factors including the interactions between the phases of ZnS and TiO₂, strong adsorption of the substrate at the surface of the ZnS/TiO₂ nanocomposites, and preassociation of the substrate and composites are responsible for this enhancement photocatalytic activity.     

MoS2/Sb2S3复合光催化剂的制备及其可见光催化性能

通过一步水热法制备出MoS₂/Sb₂S₃可见光复合催化剂,采用XRD、SEM、紫外可见漫反射（UV-Vis DRS）和XPS表征手段对MoS₂/Sb₂S₃复合光催化剂进行了表征,以罗丹明B（RhB）作为目标污染物进行降解实验。与纯Sb₂S₃和MoS₂相比,MoS₂/Sb₂S₃复合光催化剂对RhB的光催化降解具有更高的效率,表现出优异的吸附性能和光催化性能。同时在相同的实验条件下,与TiO₂、Bi₂S₃、C₃N₄、Sb₂S₃等催化剂相比,MoS₂/Sb₂S₃复合光催化剂表现出更为优异的光催化性能。此外,探究了MoS₂/Sb₂S₃复合光催化剂光催化降解机制,阐述了光催化反应机制,提供了一种适用于降解较高浓度有机废水的光催化剂制备方法,具有一定的应用价值。      

Enhanced photocatalytic activity of mesoporous TiO2 with MgO coating

To improve the photocatalytic activity of TiO₂ on decomposing anionic surfactants, MgO-coated mesoporous TiO₂ was fabricated by evaporation induced self-assembly (EISA) combined with impregnation method. MgO was uniformly dispersed on the surface of TiO₂, which played the role of stabilizing the ordered mesostructure of TiO₂ and improving the adsorption of anion surfactants, while inhibiting the crystallization of TiO₂. The powders coated with 5 wt.% MgO showed the highest photocatalytic activity for the decomposition of sodium dodecylbenzenesulfonate-6 (DBS).     

Solvothermal synthesis of In(OH)3 nanorods and their conversion to In2O3

In this work, we demonstrate that monodisperse indium hydroxide (In(OH)₃) nanorods constructed with parallel wire-like subunits have been fabricated via a acrylamide-assisted synthesis route without any template. NH₃ from the hydrolysis of acrylamide acts as the OH⁻ provider. The structure and morphology of as-prepared products have been characterized by X-ray diffraction (XRD), transmission electron microscopy (TEM), scanning electron microscopy (SEM), high-resolution transmission electron microscopy (HRTEM) and thermogravimetric analysis (TG). A detailed mechanism has been proposed on the basis of time-dependent experimental results. Furthermore, by annealing In(OH)₃ precursors at 500 °C for 3 h in air, In₂O₃ samples were obtained with the designed morphology.     

An investigation of super-hydrophilic properties of TiO2/SnO2 nano composite thin films

A sol-gel dip coating technique was used to fabricate TiO₂/SnO₂ nano composite thin films on soda-lime glass. The solutions of SnO₂ and TiO₂ were mixed with different molar ratios of SnO₂:TiO₂ as 0, 3, 4, 6, 8, 9, 10.5, 13, 15, 19.5, 25 and 28 mol.% then the films were prepared by dip coating of the glasses. The effects of SnO₂ concentration, number of coating cycles and annealing temperature on the hydrophilicity of films were studied using contact angle measurement. The films were characterized by means of scanning electron microscopy, X-ray diffraction and atomic force microscopy measurements. The nano composite thin films fabricated with 8 mol.% of SnO₂, four dip coating cycles and annealing temperature of 500 °C showed super-hydrophilicity.