氧化锌掺杂铝纳米片的制备及其气敏性能研究

采用水热法,以油酸为形貌控制剂,硝酸铝为铝源,制备了氧化锌掺杂铝纳米片,对其进行了XRD、SEM和EDS表征。考察了制备物对甲醇、乙醇、丙酮、异丙醇、正丁醇、DMF等六种气体的气敏性能,并对其气敏机理进行了简要分析。结果表明,掺杂3%Al的ZnO样品晶粒尺寸变小,为带微孔的层状纳米片,EDS能谱表明样品含有Zn、O和Al元素。样品对正丁醇、丙酮的灵敏度较高,100ppm时分别为164和70,对丙酮的响应和恢复时间分别为7s和29s。     

稀土Dy掺杂纳米SnO2薄膜的结构与气敏特性

采用真空蒸发法在玻璃衬底上制备稀土Dy掺杂Sn薄膜,对薄膜进行合适的氧化、热处理后获得Dy掺杂SnO2薄膜.用X射线衍射、场发射扫描电子显微镜、静态配气法对薄膜性能进行测试,研究不同掺Dy含量和热处理条件对SnO2薄膜的影响.结果显示,制备的SnO2薄膜呈金红石结构为n型;在相同热处理条件下,Dy掺杂可明显缩短薄膜氧化、热处理的时间;适当掺入稀土Dy可明显改善SnO2薄膜的结构、气敏特性.掺Dy 3at%后可大大提高SnO2薄膜对丙酮气体的灵敏度.     

Pt掺杂SnO2花状纳米结构的合成及其气敏性能的研究

用原位掺杂法制备了Pt/SnO2花状纳米结构.通过控制反应源物中n(Pt4+)/n(Sn4+)比率,可以获得不同Pt掺杂量的复合纳米结构.采用SEM、XRD、TEM和Raman光谱对样品的形貌、结构等进行了分析,并测试了材料的NH3气体敏感性能.结果表明,Pt掺杂的SnO2纳米花大小约为2μm,由平均直径为180nm,...     

掺杂Sb对二氧化锡纳米粉末晶粒尺寸及电阻率的影响

以SnCl4·5H2O,SbCl3为前驱体,采用So1-Gel法制备了不同Sb掺杂量的SnO2纳米粉末.对粉体的电阻率、粒度分布、比表面积进行了测量,并用X射线,扫描电镜对粉体进行了表征.结果发现,随着Sb掺杂量的提高,ATO复合纳米粉末的晶粒度减小,Sb掺杂对粉末电阻率的影响存在一拐点,Sb掺杂量较少时,粉体的电阻率随Sb含量的提高而降低,在5%～7%中有一个最小值,此后,随着Sb含量的提高,电阻率开始升高.通过对粉体粒度计算和比表面等径分析,ATO纳米粉末存在团聚现象,解决团聚问题是今后进一步研究的方向之一.     

钴掺杂二氧化锡溶剂热法制备及其气敏性能研究

以SnCl2·2H2O、CoCl2·6H2O和无水乙醇为原料,采用溶剂热法成功制备钴掺杂SnO2粉末。通过XRD、SEM和TEM对所得样品进行物相分析和形貌观察,并将其制成元件进行气敏性能测试。结果表明:所制备的钴掺杂SnO2粉末为四方相金红石结构,钴离子的掺入并没有改变SnO2的晶体结构,对SO2气体具有较高的灵敏度和较好的响应—恢复特性。     

稀土Nd掺杂纳米SnO2薄膜特性

对采用真空气相沉积法在玻璃衬底上制备的稀土Nd掺杂的SnO2薄膜,进行结构、电学及光学特性的测试分析.实验表明:氧化、热处理条件为500 ℃、45 min时样品性能好.采用一步成膜工艺法制备的SnO2薄膜晶粒度较小,随掺Nd浓度的增大,从31.516 nm减小到25.927 nm;两步成膜工艺法制备的SnO2薄膜晶粒度随掺Nd浓度的增大,从45.692 nm增至66.256 nm.XRD分析,掺Nd(5 at%)薄膜沿[110]、[101]晶向的衍射峰加强,薄膜呈多晶结构.掺Nd可使薄膜透光率下降,而薄膜的薄层电阻随热处理温度升高和掺Nd浓度的增大,呈先降后升趋势.     

SnO2纳米薄膜氢敏特性的研究

采用溶胶-凝胶法制备了SnO2氢敏纳米薄膜.将0.1和0.05mol/L的SnO2溶胶溶液旋涂在Au叉指电极衬底而制得.通过测量在不同温度下SnO2纳米氢敏薄膜的电阻信号来表征其氢敏特性.当温度为250℃时,试样的灵敏度较低,并且响应时间也比较长.温度为300℃时试样的灵敏度较高,响应时间也明显缩短.0.05mol/L溶胶溶液旋涂10层制备的样品在300℃氢气浓度为2.0×10-3时,灵敏度达到了178,响应时间为3.5s.同时实验还发现试样对氢气的响应时间随着氢气浓度的增加先增大再减小.     

掺杂型SnO2薄膜对乙醇的气敏特性

以SnCl4·5H2O、Ce(NO3)3·6H2O、CuCl2·2H2O、La(NO3)3·6H2O为原料,柠檬酸为络合剂,采用sol-gel法,浸渍提拉技术制备了纯SnO2及其掺杂薄膜.利用XRD分析方法进行了物相结构分析,研究了掺杂比对各掺杂SnO2薄膜元件气敏特性的影响.发现掺杂比相同时,掺杂Ce3+的SnO2样...     

半导体SnO2纳米晶态粉体显微结构对气敏传感器性能的影响

用ＸＲＤ、ＳＥＭ手段分析了共沉淀工艺和水热合成技术制备的半导体ＳｎＯ２纳米晶态粉体及其厚膜陶瓷材料的显微结构,结果表明两种粉体的晶粒尺寸大约７ｎｍ,但两种粉体的ＸＲＤ照片差异较大。用水热合成技术制备的粉体其颗粒是由纳米晶粒团聚而成,颗凿尺寸大约３００ｎｍ左右,具有较大的表面活性,而具有较大的表面活性,而用共沉淀工艺制备的粉体,颗粒分布较宽,活性差。两种粉体的显微结构对厚膜陶瓷材料显微结构的形成和Ｓ     

High-rate deposition of Sb-doped SnO2 films by reactive sputtering using the impedance control method

SnO₂ films doped with Sb (ATO) were deposited both on unheated glass substrates and on glass substrates that had been heated at 200 °C by reactive sputtering of an Sb-Sn alloy target with a plasma control unit (PCU) and mid-frequency (mf, 50 kHz) unipolar pulsing. The PCU feedback system monitors the oxidation states of target surface by detecting the sputtering cathode voltage (impedance control method). The mf pulse wave is approximately square-shaped; this helps to reduce arcing on the target when high power density is applied on the cathode. In case of the ATO depositions on the heated substrate at 200 °C in the “transition region” of reactive sputtering, the deposition rate was 280 nm/min, the lowest resistivity of the ATO films was 4.6 × 10^− 3 Ω cm and the optical transmittance was over 80% in the visible region of light.     

钌掺杂对氧化锡纳米线的光学和气敏性能的影响

采用热蒸发气相沉积法,以Au为催化剂制备了Ru掺杂SnO₂(SnO₂∶Ru)纳米线。研究了SnO₂∶Ru纳米线的晶体结构、微观形貌、光学特性和气敏性能。结果显示,纳米线具有完整的金红石结构,且表面平整。SnO₂∶Ru纳米线由O、Sn和Ru构成,它们的原子分数分别为62.60%、36.49%、0.91%。Ru掺杂引入施主型杂质能级导致SnO₂纳米线禁带宽度变窄,紫外波段的吸收系数明显增加,对丙酮、乙醇、乙二醇的气敏响应明显高于纯SnO₂纳米线,对丙酮的响应灵敏度最强。SnO₂∶Ru纳米线的最佳工作温度为210 ℃,对丙酮的响应/恢复时间短,理论探测极限为927×10-9,适合丙酮等挥发性有害气体的检测。     

Physical properties of electrically conductive Sb-doped SnO2 transparent electrodes by thermal annealing dependent structural changes for photovoltaic applications

We have investigated the optical and electrical characteristics of antimony (Sb)-doped tin oxide (SnO₂) films with modified structures by thermal annealing as a transparent conductive electrode. The structural properties were analyzed from the relative void % by spectroscopic ellipsometry as well as the scanning electron microscopy images and X-ray diffraction patterns. As the annealing temperature was raised, Sb-doped SnO₂ films exhibited a slightly enhanced crystallinity with the increase of the grain size from 17.1 nm at 500 °C to 34.3 nm at 700 °C. Furthermore, the refractive index and extinction coefficient gradually decreased due to the increase in the relative void % within the film during the annealing. The resistivity decreased to 8.2 × 10⁻³ Ω cm at 500 °C, but it increased rapidly at 700 °C. After thermal annealing, the optical transmittance was significantly increased. For photovoltaic applications, the photonic flux density and the figure of merit over the entire solar spectrum were obtained, indicating the highest values of 5.4 × 10¹⁴ cm⁻² s⁻¹ nm⁻¹ at 1.85 eV after annealing at 700 °C and 340.1 μA cm⁻² Ω⁻¹ at 500 °C, respectively.     

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.     

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.     

Ultraviolet photodetectors made from SnO2 nanowires

SnO₂ nanowires can be synthesized on alumina substrates and formed into an ultraviolet (UV) photodetector. The photoelectric current of the SnO₂ nanowires exhibited a rapid photo-response as a UV lamp was switched on and off. The ratio of UV-exposed current to dark current has been investigated. The SnO₂ nanowires were synthesized by a vapor-liquid-solid process at a temperature of 900 °C. It was found that the nanowires were around 70-100 nm in diameter and several hundred microns in length. High-resolution transmission electron microscopy (HRTEM) image indicated that the nanowires grew along the [200] axis as a single crystallinity. Cathodoluminescence (CL), thin-film X-ray diffractometry, and X-ray photoelectron spectroscopy (XPS) were used to characterize the as-synthesized nanowires.     

静电纺丝法制备CuO/SnO2复合材料及其气敏特性研究

为研究p型材料和n型材料复合时气敏特性的变化,采用静电纺丝法分别制备了CuO、SnO_2以及3种比例混合的CuO/SnO_2复合纳米纤维材料,并通过XRD及SEM对其形貌、微观结构等进行表征.测试了该5种材料对丙酮、甲醛、甲醇、乙醇、甲苯等VOC气体的敏感特性.研究表明,CuO/SnO_2=2∶1的复合材料对丙酮、甲苯和乙醇的的响应值有一定提高;CuO/SnO_2=1∶1的复合材料对丙酮具有很高响应的同时,对乙醇和甲苯的响应产生了一定的抑制作用,从而大大提高了材料的选择性.其机理是:半导体材料复合后,在复合材料的表面会有更多的氧吸附,导致更多的VOC气体在半导体材料表面发生反应,使材料的电阻值变化更加明显,提高了材料的响应值.     

Silicon doped SnO2 films for liquid petroleum gas sensor

Silicon doped SnO₂ films were synthesized by sputtering SnO₂ layer onto glass substrates with appropriate amount of silicon sputtered onto them. The bilayer structures were subjected to rapid thermal annealing for the incorporation of Si in SnO₂ matrix. The films thus obtained were characterized by measuring optical and microstructural properties. Liquid petroleum gas (LPG) sensing properties were also investigated. FTIR and Raman studies were also carried out on these films, both, before and after LPG exposure.     

基于SnO2/Fe3O4粒子电极的三维电极体系的电催化性能

通过水热法合成复合金属氧化物SnO_2/Fe_3O_4粒子电极,然后采用X射线衍射(XRD)、扫描电子显微镜(SEM)、X射线光电子能谱(XPS)、磁滞回线等技术分别对粒子电极的晶体组分、形貌、元素组成和分子结构以及粒子电极的磁性特征进行表征。采用循环伏安法分析了三维电极系统的电化学性能,并进行了电催化氧化降解罗丹明B(RhB)的实验。结果表明,SnO_2/Fe_3O_4粒子电极负载稳定、导电性强、便于回收再利用,有利于电催化氧化降解反应。三维电极降解罗丹明B的析氧电流高于其他电极体系,电催化活性效果明显,90min内罗丹明B的降解率为100%、TOC去除率为83%,反应中产生的·OH是降解有机物的主要活性基。粒子电极在重复利用5次的情况下,对罗丹明B的降解率仍保持93%以上、TOC去除率保持在77%以上,具有稳定的电催化性能。     

Photocatalytic performance of very thin TiO2/SnO2 stacked-film prepared by magnetron sputtering

TiO₂/SnO₂ stacked-layers are synthesized by reactive sputter deposition on the glass substrate. Very thin TiO₂/SnO₂ bilayer-photocatalysts exhibited a very high photocatalytic activity for a degradation of gaseous acetaldehyde. Both the control of an electronic structure of TiO₂ overlayer in the near-surface region and the interfacial separation of photogenerated electrons/holes in the TiO₂/SnO₂ stacked-layer are keys to improve the photocatalytic performance.