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金属离子掺杂纳米SnO2材料的气敏性能及掺杂机理 总被引:2,自引:0,他引:2
以SnCl4·5H2O为原料合成纳米SnO2,并以其为基底材料分别以离子形式掺杂Ag^+、Ni^2+、Ce^3+、Sb^2+等作为气敏材料,制作旁热式气敏元件.研究了其对甲醇、乙醇气体的气敏性能.结果发现,适量的金属离子掺杂可提高SnO2的气敏性能,其中掺Ag^+效果最佳,可显著提高SnO2对甲醇、乙醇气体的灵敏度.在工作温度为360℃时,对体积浓度为400×10^-6的乙醇、甲醇气体灵敏度分别为121和66.掺Sb^2+可提高SnO2的导电性,在温度为200℃时,电阻值由180kΩ降至4kΩ.用Materials Studio软件对掺杂不同金属的SnO2的能带结构进行了理论计算,分析表明,掺杂使SnO2能带带隙宽度由掺杂前的2.65eV减少为2.02~2.62eV,相应元件电阻阻值的减少与带隙宽度变化趋势一致,带隙宽度是影响SnO2传感器工作温度高低的重要因素. 相似文献
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掺In纳米ZnO、CdS薄膜结构、光学特性分析 总被引:1,自引:0,他引:1
采用真空气相沉积法在玻璃衬底上制备纳米级ZnO和CdS薄膜.研究掺In和热处理对ZnO、CdS薄膜结构、光学特性的影响.实验给出,适当掺杂能够明显改善纳米ZnO、CdS薄膜的物相结构,ZnO薄膜的晶粒尺寸随掺杂含量的增加而减小,CdS薄膜晶粒尺寸随掺杂含量的增加而变大,但薄膜的光透射性有所降低.在短波范围内,ZnO薄膜的光透率好于CdS薄膜;在500 nm~1000 nm范围内,CdS薄膜的光透率好.掺In后ZnO薄膜的光学带宽从3.2eV减小至2.85 eV;掺In后CdS薄膜光学带宽从2.42 eV减小至2.35eV. 相似文献
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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. 相似文献
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《中国粉体技术》2017,(2):44-48
采用Ta元素掺杂TiO_2光催化剂,研究掺杂引起的光催化效率变化、微观结构改变和催化剂改性的机制。采用溶胶凝胶法制备不同浓度的Ta元素掺杂纳米TiO_2光催化剂,并通过降解罗丹明B表征其光催化性能。通过X射线衍射、拉曼光谱和X射线光电子能谱分析Ta掺杂纳米TiO_2催化剂晶相、微观结构、元素组成和化合价等。结果表明:Ta掺入纳米TiO_2催化剂后,Ta原子将取代Ti的位置,以Ta~(5+)形式存在于TiO_2晶格中,促进掺杂样品中形成氧空位,可以有效提高电子密度,并抑制光生载流子复合,从而提高催化效率。当掺杂比例n_(Ta)/n_(Ti)为3%时,光催化效率最高,光照2 h对罗丹明B降解率高达83.8%,是未掺杂样品的2倍以上。 相似文献
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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. 相似文献
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利用化学水浴法在硅纳米孔柱陈列(Si-NPA)上沉积了硫化镉(CdS)纳米晶,制得硫化镉/硅纳米孔柱阵列(CdS/Si-NPA)纳米异质结,并对非掺杂和锌(Zn)掺杂CdS/Si-NPA进行表征。研究结果表明:CdS/Si-NPA的结构保持了Si-NPA的规则阵列结构,通过加入一定量的氯化锌,实现了Zn对CdS的掺杂,Zn掺杂后的CdS晶粒大小由约18.1nm减小为约17.6nm,Zn的掺入导致了CdS/Si-NPA的光学带隙由约2.45eV增大到约2.49eV,Zn的掺杂能有效调控CdS带隙。 相似文献
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Maria Bardosova Martyn E. Pemble Ian M. Povey Richard H. Tredgold 《Advanced materials (Deerfield Beach, Fla.)》2010,22(29):3104-3124
The area of colloidal photonic crystal research has attracted enormous attention in recent years as a result of the potential of such materials to provide the means of fabricating new or improved photonic devices. As an area where chemistry still predominates over engineering the field is still in its infancy in terms of finding real applications being limited by ease of fabrication, reproducibility and ‘quality’‐ for example the extent to which ordered structures may be prepared over large areas. It is our contention that the Langmuir‐Blodgett assembly method when applied to colloidal particles of silica and perhaps other materials, offers a way of overcoming these issues. To this end the assembly of silica and other particles into colloidal photonic crystals using the Langmuir‐Blodgett (LB) method is described and some of the numerous papers on this topic, which have been published, are reviewed. It is shown that the layer‐by‐layer control of photonic crystal growth afforded by the LB method allows for the fabrication of a range of novel, layered photonic crystals that may not be easily assembled using any other approach. Some of the more interesting of these structures, including so‐called heterostructured photonic crystals comprising of layers of spheres having different diameters are presented and their optical properties described. Finally, we offer our comments as to future applications of this interesting technology. 相似文献
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We report the rapid formation of photonic crystal structures by assembly of uniform nonmagnetic colloidal particles in ferrofluids using external magnetic fields. Magnetic manipulation of nonmagnetic particles with size down to a few hundred nanometers, suitable building blocks for producing photonic crystals with band gaps located in the visible regime, has been difficult due to their weak magnetic dipole moment. Increasing the dipole moment of magnetic holes has been limited by the instability of ferrofluids toward aggregation at high concentration or under strong magnetic field. By taking advantage of the superior stability of highly surface-charged magnetite nanocrystal-based ferrofluids, in this paper we have been able to successfully assemble 185 nm nonmagnetic polymer beads into photonic crystal structures, from 1D chains to 3D assemblies as determined by the interplay of magnetic dipole force and packing force. In a strong magnetic field with large field gradient, 3D photonic crystals with high reflectance (83%) in the visible range can be rapidly produced within several minutes, making this general strategy promising for fast creation of large-area photonic crystals using nonmagnetic particles as building blocks. 相似文献
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Romanov SG Korovin AV Regensburger A Peschel U 《Advanced materials (Deerfield Beach, Fla.)》2011,23(22-23):2515-2533
We review the recently emerged class of hybrid metal-dielectric colloidal photonic crystals. The hybrid approach is understood as the combination of a dielectric photonic crystal with a continuous metal film. It allows to achieve a strong modification of the optical properties of photonic crystals by involving the light scattering at electronic excitations in the metal component into moulding of the light flow in series to the diffraction resonances occurring in the body of the photonic crystal. We consider different realizations of hybrid plasmonic-photonic crystals based on two- and three-dimensional colloidal photonic crystals in association with flat and corrugated metal films. In agreement with model calculations, different resonance phenomena determine the optical response of hybrid crystals leading to a broadly tuneable functionality of these crystals. 相似文献
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目的 总结光子晶体材料在机械力致变色方面的研究现状,基于机械力致变色光子晶体的特点进行展望,为进一步研究和应用提供参考.方法 基于机械力的施加方式,从拉伸变色和压缩变色两个方面系统介绍了机械力致变色光子晶体的制备方法、光学性能以及机械性能,并分析比较了这两种光子晶体材料的应用现状和前景.结论 机械力致变色光子晶体在结构上有多种形式,包括嵌入胶体阵列的弹性体光子晶体、胶体交联光子晶体、层状光子晶体、链状光子晶体等,近些年这些光子晶体已经可以达到明亮的结构色和应变能力.机械力致变色光子晶体因其形式的多样性和良好的光学、机械性能,使其在应力检测、人体运动状态监测、防伪、显示等方面得以应用,具有很大的实际应用潜力. 相似文献
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G. Subramania K. Constant R. Biswas M. M. Sigalas K.‐M. Ho 《Advanced materials (Deerfield Beach, Fla.)》2001,13(6):443-446
Recent work on a technique for fabricating inverse fcc photonic crystals from a colloidal system of monodisperse microspheres and titania nanoparticles is described. The technique can be used to produce photonic crystals with other background materials that are available as nanoparticles. The Figure shows the Moiré pattern of a typical photonic crystal sample. 相似文献
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Layer‐by‐Layer Approach to (2+1)D Photonic Crystal Superlattice with Enhanced Crystalline Integrity 下载免费PDF全文
Lijing Zhang Zhuo Xiong Liang Shan Lu Zheng Tongbo Wei Qingfeng Yan 《Small (Weinheim an der Bergstrasse, Germany)》2015,11(37):4910-4921
Large‐area polystyrene (PS) colloidal monolayers with high mechanical strength are created by a combination of the air/water interface self‐assembly and the solvent vapor annealing technique. Layer‐by‐layer (LBL) stacking of these colloidal monolayers leads to the formation of (2+1)D photonic crystal superlattice with enhanced crystalline integrity. By manipulating the diameter of PS spheres and the repetition period of the colloidal monolayers, flexible control in structure and stop band position of the (2+1)D photonic crystal superlattice has been realized, which may afford new opportunities for engineering photonic bandgap materials. Furthermore, an enhancement of 97.3% on light output power of a GaN‐based light emitting diode is demonstrated when such a (2+1)D photonic crystal superlattice employed as a back reflector. The performance enhancement is attributed to the photonic bandgap enhancement and good angle‐independence of the (2+1)D photonic crystal superlattice. 相似文献
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The inside cover illustrates an approach to creating line defects embedded in the interior of a self‐assembled photonic crystal, as reported by Zhao and co‐workers on p. 1917. Photoresist patterns are first constructed on the surface of a silica opal film by conventional optical photolithography. After regrowth of the silica colloidal crystal, photoresist line defects are successfully introduced into the self‐assembled silica colloidal crystal. Further processing results in an inverse opal with air‐core line defects embedded in its interior, which provides a prototype for future optical waveguide devices based on self‐assembled three‐dimensional photonic crystals. 相似文献
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Ganesh N Zhang W Mathias PC Chow E Soares JA Malyarchuk V Smith AD Cunningham BT 《Nature nanotechnology》2007,2(8):515-520
Colloidal quantum dots display a wide range of novel optical properties that could prove useful for many applications in photonics. Here, we report the enhancement of fluorescence emission from colloidal quantum dots on the surface of two-dimensional photonic crystal slabs. The enhancement is due to a combination of high-intensity near fields and strong coherent scattering effects, which we attribute to leaky eigenmodes of the photonic crystal. By fabricating two-dimensional photonic crystal slabs that operate at visible wavelengths and engineering their leaky modes so that they overlap with the absorption and emission wavelengths of the quantum dots, we demonstrate that the fluorescence intensity can be enhanced by a factor of up to 108 compared with quantum dots on an unpatterned surface. 相似文献