SnO2纳米颗粒制备及其对溶胶-凝胶Sb:SnO2薄膜性能的影响

以Sn(OEt)2为起始原料,采用水热晶化法合成了分散性良好的金红石结构的SnO2纳米颗粒.采用X射线衍射对其进行了表征,表明SnO2纳米颗粒的结晶性良好,颗粒尺寸小于10nm.将合成的SnO2纳米颗粒均匀分散到Sb:SnO2镀膜液中,经陈化后制成镀膜溶胶,以溶胶-凝胶浸渍镀膜工艺制备纳米颗粒掺杂Sb:SnO2薄膜.分别采用范德堡(Van Der Pauw)法、UV/VIS分光光度计和FTIR中红外分析仪测量并分析膜层的导电性能、光学性能及结构特征,研究了导电纳米颗粒添加对Sb:SnO2薄膜电性能、光学性能和结构的影响.     

SnO2纳米晶体的液相法可控合成研究进展

SnO2纳米晶体广泛应用于电极材料、气敏材料及催化材料.概述了纳米SnO2结构液相法可控合成技术的研究现状及进展,重点介绍了均匀沉淀法、微乳液法、溶胶-凝胶法和水热法4种主要合成方法,并结合各种方法的特点对其在纳米SnO2各应用领域的发展前景进行了分析.     

TiO2/SnO2纳米晶膜的制备及其电学性能研究

采用丝网印刷的方式制备了TiO2纳米晶薄膜,然后在其上采用浸泡的方式制备了SnO2纳米晶薄膜,形成TiO2/SnO2膜结构的光阳极并应用于染料敏化太阳能电池。用SEM对样品进行了结构形貌分析,用电化学工作站研究表征了SnO2的浸泡溶液浓度和浸泡时间对光阳极的调制改性作用。SEM分析表明在TiO2纳米晶薄膜表面生长的SnO2纳米晶薄膜晶粒比TiO2更加细小,电学性能研究表明TiO2薄膜经过0.4 mol/L SnO2溶液浸泡处理50 min能对TiO2薄膜的结构及性能起到很好的改善作用,电池的光电转化效率提高了约7%。     

氮掺杂对SnO2薄膜光电性能的影响

SnO2薄膜具有透明导电的特性,因而被制成透明电极而广泛应用于平板显示器和太阳能电池中。研究表明,经掺杂的薄膜具有更优异的光电性能,然而传统的掺杂元素Sb,Te或F较为昂贵且有毒性,因此,掺氮将有望解决上述问题。本文利用反应射频磁控溅射法制备出不同氧含量的SnO2以及氮掺杂SnO2薄膜,并分析了薄膜的形貌结构及光电性能。结果表明:薄膜沉积过程中氧分压和氮掺杂对薄膜性能影响较大。在SnO2薄膜中,晶粒呈包状形态,随着氧分压的增加,晶粒取向从(101)转向(110)方向,晶粒尺寸逐渐变小,可见光透光率提升到80%以上,光学带隙增加到4.05 eV;在氮掺杂SnO2薄膜中,晶粒呈四棱锥形态,晶粒取向为(101)方向,随着氧分压的增加,可见光的透过率同样提升到80%以上,光学带隙增加到3.99 eV。SnO2薄膜和氮掺杂SnO2薄膜的电阻率最低分别达到1.5×10-1和4.8×10-3Ω.cm。     

退火处理对SnO2:F薄膜光电性能的影响

SnO2∶F薄膜作为low-e玻璃的表面功能层材料,广泛应用于节能镀膜玻璃。Low-e玻璃在后期退火(深加工)后,其性能的变化已经引起了学术研究和实际应用方面的的关注。我们对于用化学气相沉积法在玻璃表面沉积的约250nm厚的SnO2∶F薄膜进行不同的退火处理。并通过一系列的研究,结果发现,薄膜的结构、组成、电学、光学性能在氮气和空气两种不同的退火气氛下会有显著的变化。SnO2∶F薄膜的Low-e性能经过空气中高温退火后下降明显。通过计算对比退火后SnO2∶F薄膜的晶格常数和晶胞尺寸,提出了一种对于薄膜Low-e性能下降的合理解释。     

复合电沉积制备SnO2/TiO2薄膜及其光电催化性能

为了寻求廉价、高效和稳定的光催化剂,用复合电沉积技术在紫铜片上制备了Sn/TiO2薄膜,经300℃热氧化使之形成SnO2/TiO2复合电极.利用SEM,XRD对薄膜进行了表征,以甲基橙为模型化合物,对复合电极的光催化和光电催化性能进行了测定.研究表明:该薄膜由0.3~1μm的颗粒构成,每个颗粒又由纳米晶粒形成;电极具有多孔结构,膜中的SnO2以两种不同的晶体结构存在;在薄膜质量相等的情况下,SnO2/TiO2薄膜的光催化活性是纯TiO2粒子膜的2.87倍;外加一定偏压下,其催化性能大幅度提高.     

SnO2/Fe3O4磁性光催化微纳米材料的制备与性能研究

以磁性纳米颗粒Fe3O4为核,SnCl4.5H2O、氨水、无水乙醇为原料,采用液相共沉淀法在Fe3O4表面包覆一层SnO2光催化剂。采用X射线衍射仪(XRD)及扫描电镜(SEM)分析了其成分和表面形貌。结果显示:Fe3O4纳米颗粒在实验过程中发生了团聚,尺寸增大;当Fe3O4与SnCl4.5H2O物质的量比为(1∶2)～(1∶4)时,SnO2能被较好地包覆在Fe3O4表面,形成核-壳结构的SnO2/Fe3O4复合光催化材料;600℃热处理能够形成结晶性良好的SnO2晶体,但此时Fe3O4转变为Fe2O3,失去了磁性。     

SnO2/TiO2纳米管阵列对304不锈钢的阴极保护效果

目前,就SnO2/TiO2复合薄膜对不锈钢的光生阴极保护效果的研究有待深入。以两步阳极氧化法在钛箔表面制备TiO2纳米管阵列膜,并将其浸渍在不同浓度的SnO2溶液中,得到了SnO2/TiO2复合纳米管阵列材料。采用扫描电镜(SEM)、X射线衍射(XRD)、X射线光电子能谱(XPS)研究了其表面形貌、晶型,用电化学方法研究了SnO2/TiO2复合纳米管阵列对304不锈钢的光生阴极保护特性及耐腐蚀性能。结果表明:TiO2纳米管排列规整,孔径约80~150 nm;以0.5 mol/L SnO2溶胶制备的SnO2/TiO2半导体供给外电路的电子数最高;在紫外光照1 h时,TiO2和SnO2/TiO2均对304不锈钢有一定的光生阴极保护作用;闭光后SnO2/TiO2光生电极在较长时间内维持较低电位,低于其在3.5%NaCl溶液中的自腐蚀电位,延时阴极保护作用可以达到8.5 h。     

Cu2ZnSnS4纳米颗粒及其薄膜的制备与表征

采用热注入法,在油胺(OLA)中合成出Cu2ZnSnS4(CZTS)纳米颗粒,并在玻璃衬底上制备了薄膜,研究了不同合成温度对纳米颗粒生成的影响.通过X射线衍射仪、拉曼光谱仪、透射电子显微镜、扫描电子显微镜、紫外可见分光光度计对所得纳米晶材料的结构与成分、颗粒大小与形貌、光吸收谱进行了测试分析.研究结果表明:采用热注入法的最佳合成温度在260℃左右,该温度下生成的多晶CZTS纳米颗粒尺寸约10 nm,分散性良好,光学禁带宽度约1.5 eV.     

柱状晶形貌TiO2膜厚对FTO/TiO2镀膜玻璃光催化活性影响

采用溶胶凝胶法,在FTO(SnO2:F)低辐射镀膜玻璃衬底上制备了柱状晶体结构的TiO2薄膜,获得双层结构FTO/TiO2镀膜玻璃样品.研究了TiO2薄膜厚度对FTO/TiO2镀膜玻璃样品的光催化活性、低辐射性能以及透光性能的影响.结果表明,FTO/TiO2镀膜玻璃样品光催化活性随着TiO2薄膜厚度的增加先升高后下降,在TiO2薄膜厚度为300 nm时光催化活性最佳;低辐射性能随着TiO2薄膜厚度的增加而下降,但TiO2薄膜厚度为300 nm时仍然具备一定的低辐射性能;透光性能与TiO2薄膜膜厚的关系不大,可见光透射比保持在72%左右;表面平均粗糙度约为1 nm,表面光滑,不易沾染油污灰尘.该镀膜玻璃在保证低辐射建筑节能和透光的前提下,兼具光催化自清洁功能,具有很好的应用前景.     

Preparation of porous SnO2 helical nanotubes and SnO2 sheets

We report a surfactant-free chemical solution route for synthesizing one-dimensional porous SnO₂ helical nanotubes templated by helical carbon nanotubes and two-dimensional SnO₂ sheets templated by graphite sheets. Transmission electron microscopy, X-ray diffraction, cyclic voltammetry, and galvanostatic discharge–charge analysis are used to characterize the SnO₂ samples. The unique nanostructure and morphology make them promising anode materials for lithium-ion batteries. Both the SnO₂ with the tubular structure and the sheet structure shows small initial irreversible capacity loss of 3.2% and 2.2%, respectively. The SnO₂ helical nanotubes show a specific discharge capacity of above 800 mAh g⁻¹ after 10 charge and discharge cycles, exceeding the theoretical capacity of 781 mAh g⁻¹ for SnO₂. The nanotubes remain a specific discharge capacity of 439 mAh g⁻¹ after 30 cycles, which is better than that of SnO₂ sheets (323 mAh g⁻¹).     

SnO2和SnO2-Ag薄膜的电学特性

用磁控溅射法在集成了铂加热电极的Si基膜片型微结构单元上制备了SnO     

Silver layer instability in a SnO2/Ag/SnO2 trilayer on silicon

Trilayers of SnO₂/Ag/SnO₂ deposited on oxidized Si (100) substrates at room temperature become unstable after annealing at 100 °C and 200 °C, exhibiting five phenomena - formation of internal Ag hillocks, cracking of the top SnO₂ layer above internal Ag hillocks, penetration of Ag/Ag grain boundaries by SnO₂ leading to grain pinch-off, formation of Ag whiskers and islands on the free surface of the SnO₂ through the cracked top layer, and void formation in the Ag layer. The possible driving forces and evolution path for the observed instabilities resulting from thermal expansion mismatch stresses and the reduction in interfacial energy are discussed.     

Lithographic patterning of benzoylacetone modified SnO2 and SnO2:Sb thin films

The synthesis of directly UV-photopatternable pure and antimony-doped organo-tin materials is presented. UV-photopatternability has been achieved by using the synthesized benzoylacetone modified tin and antimony 2-isopropoxyethoxides. Photopatterned pure and antimony-doped organo-tin films are crystallized by thermal annealing in order to obtain conductive SnO₂ and Sb:SnO₂ thin films. The molar ratio between benzoylacetone and metal alkoxides has to be 2 in order to obtain crack-free, good-quality structures. The effects of UV-irradiation, increasing antimony doping level and benzoylacetone concentration on the electrical properties of the single-layered films are analyzed. The highest obtained conductivity was 20 S/cm. Benzoylacetone concentration and UV-irradiation has only a negligible effect on the film electrical conductivities.     

Characterizations of SnO2 and SnO2:Sb thin films prepared by PECVD

Structural characterizations of tin oxide (SnO₂) thin films, deposited by plasma-enhanced chemical vapor deposition (PECVD), were investigated with scanning electron microscope (SEM), X-ray diffraction (XRD), and X-ray photoelectron spectroscopy (XPS). The results show that the films are porous, the crystalline structure transforms from crystalline to amorphous phase as deposition temperature changes from 500°C to 200°C, and the chemical component is non-stoichiometric (Sn:O is 1.0716 prepared at 450°C with a value of O₂ flow 3.5 l/min). Sheet resistance of the thin films decreases with increasing of deposition temperature. Whereas, sheet resistance increases with increasing of oxygen flow. Tin oxide doped with antimony (SnO₂:Sb) thin films prepared by same method have a better selectivity to alcohol than to carbon monoxide; the maximum sensitivity is about 220%. The gas-sensing mechanism of SnO₂ thin films is commentated.     

One-pot synthesis of intestine-like SnO2/TiO2 hollow nanostructures

In the present study the intestine-like binary SnO₂/TiO₂ hollow nanostructures are one-pot synthesized in aqueous phase at room temperature via a colloid seeded deposition process in which the intestine-like hollow SnO₂ spheres and Ti(SO₄)₂ are used as colloid seeds and Ti-source, respectively. The novel core (SnO₂ hollow sphere)-shell (TiO₂) nanostructures possess a large surface area of 122 m²/g (calcined at 350 °C) and a high exposure of TiO₂ surface. The structural change of TiO₂ shell at different temperatures was investigated by means of X-ray diffraction and Raman spectroscopy. It was observed that the rutile TiO₂ could form even at room temperature due to the presence of SnO₂ core and the unique core-shell interaction.     

Preparation of antimony-doped SnO2 nanocrystallites

The antimony-doped SnO₂ nanocrystallite was synthesised by the co-precipitation reaction and subsequent calcination from the antimony(III) chloride and tin(IV) chloride. The crystal size, pore size distribution and properties of the nanocrystalline powders were examined by differential thermal analysis, thermogravimetric analysis, X-ray diffraction and desorption isotherm(Barrett-Joyner-Halenda method). Calcination of the precipitate powder at 650°C led to the formation of Sb-SnO₂ nanocrystallite of ∼6 nm in crystal size. Most of the pores in the nanocrystallite are about 5-10 nm in diameter. Effect of doped antimony on the crystal size of the nanocrystallite is discussed.     

In-situ preparation of TiO2/SnO2 nanocrystalline sol for photocatalysis

A novel preparation method to synthesize TiO₂/SnO₂ nanocrystalline sol under mild conditions was presented. Ti(OC₄H₉)₄ used as a precursor was hydrolyzed in the rutile SnO₂ nanocrystalline sol, and in-situ formed TiO₂/SnO₂ nanocrystalline sol. The crystal structure, morphology and photocatalysis performance of samples were investigated. The results show that the additional rutile SnO₂ nano grains serve as heterogeneous crystal nucleus and exhibite the inducing effect on TiO₂ grains growth, thus leading to the changes in crystalline phase and particle morphology. In addition, the photoluminescence (PL) spectra analysis indicates that TiO₂/SnO₂ composite structure induces a better charge separation, and thus the photocatalytic activity of TiO₂/SnO₂ sol is increased significantly compared with TiO₂ sol.     

Nanocrystalline SnO2 and Au:SnO2 thin films prepared by direct current magnetron reactive sputtering

Nanocrystalline pure and gold doped SnO₂(Au:SnO₂) films were prepared on unheated glass substrates by dc magnetron reactive sputtering and, subsequently, the as deposited films were annealed in air. The films structure, surface morphology, photoluminescence, electrical and optical properties were investigated. After annealing the as deposited SnO₂ films, crystallinity increased and the surface roughness decreased. The intensity of PL peaks increases sharply with the annealing temperature. The optical transmittance of the films was around 89% after annealing the as deposited SnO₂ films at 450 °C. The as deposited Au:SnO₂ films show better crystallinity than the as deposited SnO₂ films, the average grain size was around 4.4 nm. The emission peaks of Au:SnO₂ films are slightly blue shifted as compare to undoped SnO₂ films. The Au:SnO₂ films show the lowest electrical resistivity of 0.001 Ωcm with optical transmittance of 76%, after annealing at 450 °C.     

TiO2 coated SnO2 nanosheet films for dye-sensitized solar cells

TiO₂-coated SnO₂ nanosheet (TiO₂-SnO₂ NS) films about 300 nm in thickness were fabricated on fluorine-doped tin oxide glass by a two-step process with facile solution-grown approach and subsequent hydrolysis of TiCl₄ aqueous solution. The as-prepared TiO₂-SnO₂ NSs were characterized by scanning electron microscopy and X-ray diffraction. The performances of the dye-sensitized solar cells (DSCs) with TiO₂-SnO₂ NSs were analyzed by current-voltage measurements and electrochemical impedance spectroscopy. Experimental results show that the introduction of TiO₂-SnO₂ NSs can provide an efficient electron transition channel along the SnO₂ nanosheets, increase the short current density, and finally improve the conversion efficiency for the DSCs from 4.52 to 5.71%.