共查询到19条相似文献,搜索用时 375 毫秒
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本文提出了一种新的调节人工欧泊晶体的光学带隙的方法.采用改进的溶剂蒸发法将单分散SiO2微球组装成在红外光区具有光子带隙的人工欧泊,采用化学还原法向欧泊中填充高折射率材料Se,改变其光学带隙特性.采用扫描电子显微镜(SEM)、X射线衍射和可见-近红外光谱仪(VIS-NIR)等对Se-SiO2三维光子晶体的形貌、结构和光学性能进行了观察测试.研究结果表明Se以纳米晶粒的形式均匀地包覆在SiO2微球表面,与相同晶格周期的SiO2光子晶体相比,Se-SiO2光子晶体的带隙发生明显的红移. 相似文献
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以糯米浆为有机调控物质,二氧化碳提供碳源仿生制备出多种形貌的碳酸钙晶体.探索了矿化时间、钙离子浓度对碳酸钙晶体形貌和晶型的影响.采用扫描电子显微镜(SEM)、傅里叶红外光谱仪(FT-IR)和X射线衍射仪(XRD)对制备的碳酸钙表观形貌及结构进行表征.扫描电镜结果表明:以糯米浆为有机调控物质,钙离子浓度和矿化时间对碳酸钙晶体的形貌有一定的影响;XRD及FT-IR图谱表明制备的碳酸钙晶型为方解石和球霰石. 相似文献
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利用水热法通过改变填充溶剂的种类制备了不同形貌的CaTi2 O4(OH)2粉体.采用X射线衍射仪和扫描电子显微镜对粉体的相结构和微观形貌进行了分析,并结合粉体在紫外-可见吸收光下对罗丹明B的吸附率及光降解率进行了表征.研究了不同填充溶剂对CaTi2 O4 (OH)2的相结构、微观形貌、能带宽度以及光催化性能的影响.结果表明:乙醇和乙二醇作为填充溶剂时会抑制晶体的生长和发育,可获得纳米线状或团状CaTi2 O4 (OH)2粉体,对罗丹明B表现出较佳的吸附特性;无填充溶剂以及以水和环己烷分别作为填充溶剂可获得具有片状结构的CaTi2O4(OH)2粉体.填充环己烷能够促进CaTi2O4(OH)2相的生长和发育,结晶度最高达到了78.04;,在紫外可见光3h下对罗丹明B降解率达到91.6;. 相似文献
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利用改良的St6ber法制成了粒径均一的SiO2胶体颗粒,胶体微球颗粒平均粒径为200 nm.保持SiO2悬浮液体积分数相同,对双基片自组装垂直沉积进行改造,改变夹层厚度,沉积得到厚度不同的SiO2光子晶体薄膜.利用扫描电子显微镜观察了膜厚不同的SiO2光子晶体薄膜样品的表面以及断面微观形貌,测试了样品的光反射性能,此外还讨论了光子晶体薄膜厚度对样品表面的形貌以及样品光反射性能带来的影响. 相似文献
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以聚乙烯醇(PVA)和聚苯乙烯磺酸钠(PSSS)分别与十六烷基三甲基溴化铵(CTAB)组成混合模板,在CaCl2、Na2CO3体系中调控合成CaCO3晶体.考察了不同CTAB浓度及结晶温度对碳酸钙晶体的影响.通过扫描电子显微镜(SEM)、红外光谱(FT-IR)及X射线衍射(XRD)等技术对晶体的形貌和结构进行了表征,并对不同形貌碳酸钙的形成机理进行了探讨.结果表明:在PVA和CTAB模板中,5℃为方解石椭球状聚集体,25℃时为菊花状、立方状的方解石和球霰石的混晶,90℃时得到针状文石晶簇.以PSSS和CTAB模板调控下的碳酸钙,5℃时为球状的方解石和球霰石的混晶,25℃为颗粒均匀的球形球霰石,90℃时得到了花朵状文石.不同形貌及晶型碳酸钙的生成源自聚合物与CTAB组成复合物结构的差异. 相似文献
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以氯化铟(InCl3·4H2O)和白磷(P4)为反应物,硼氢化钠(NaBH4)为还原剂,在较低的反应温度下采用溶剂热法制备出了InP纳米球.利用X射线衍射仪(XRD)、场发射扫描电镜(FESEM)和光致发光光谱(PL)对所制备产物的结构、形貌和发光性能进行了分析和表征.结果表明:在适当的温度下可以制备出尺寸为300 nm左右的纳米球,通过改变反应条件可以改变产物的尺寸、形貌.同时,从动力学方面对溶剂热法制备InP纳米球的反应机理进行了初步探讨. 相似文献
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Oleh V. Ohiienko V. N. Moiseyenko T. V. Shvets 《Molecular Crystals and Liquid Crystals》2020,701(1):72-81
AbstractThis paper presents a systematic photoluminescence spectra study of the (111) growth surface of an opal photonic crystal whose pores were filled with salt Europium (III) acetate monohydrate (C6H9EuO6×H2O). Ultraviolet excitation was provided by semiconductor laser operating at wavelengths of 405?nm. Emission spectra were measured both for free-form salt samples and for salt in opal pores annealed at various temperatures up to 1000?°C. The influence of changes in the coordination environment of europium ions on the luminescence spectra in the process of dehydration and salt decomposition up to Eu2O3 is established. Differences in the spectra of salt in the pores of opal were revealed compared with the spectra in the free state. 相似文献
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Ming Fu Jinfang Cui Mei Yang Rong Jiang Dawei He Yongsheng Wang 《Crystal Research and Technology》2012,47(12):1249-1254
ZnO is an important wide bandgap compound semiconducting material and exhibits a wide range of novel structures that can be grown by tuning the growth rates along its fast growth directions. Highly ordered macroporous materials by using colloidal crystal template method are of great interest in many fields including photonic crystals and catalysts. In this study, ZnO with highly ordered porous structure was deposited by different electrochemical method. Nanomeshes, inverse opal structures, and spherical/ellipsoidal particles with pore arrays are fabricated by the colloidal crystals with different functional groups. The template effects on the morphology of the macroporous structures for different surface groups are studied. All the nanomeshes grows along the {111} plane family by colloidal crystals without functional groups. Disordered arrangements of the nanomeshes are induced by colloidal crystals with hydroxyl groups. The inverse opal structures fabricated by template with carboxyl groups are smoother in surface. 相似文献
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Wei Wu Ke Yu Huibing Mao Zhengli Zhang Ziqiang Zhu 《Crystal Research and Technology》2010,45(4):393-397
Two‐dimensional (2D) photonic crystal of ZnO pillars was synthesized on silicon substrate by the combination of template method and vapor‐phase transport method. The microstructure and morphology of the ZnO photonic crystal was evaluated by using scanning electron microscope (SEM) and X‐ray diffraction (XRD). Large‐area specular reflectance measurements showed the presence of photonic stop band. The effect of the photonic band gap and the special structure on the photoluminescence (PL) properties of ZnO photonic crystal has been investigated. Both suppression and enhancement in the PL were observed. Raman scattering analyses demonstrated that the defect of ZnO photonic crystal exists in this experiment. (© 2010 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim) 相似文献
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The synthesis optimization of three-dimensional photonic crystals (direct and inverse opals) is discussed in terms of the influence of processing parameters on the final optical quality. A colloidal/sol–gel route, starting with the self-organization of polystyrene microspheres into opal structures by convective self-assembly, followed by infiltration with a dielectric matrix precursor sol and heat treatment, has been followed. Several substrate hydrophilization methods have been tested and different substrates. Sol–gel infiltration of the opal template interstices with silica was achieved by dip-coating or micro-syringe application and it was followed by removal of the polymeric template. The concentration of the colloidal sol, containing polystyrene spheres of 235 or 460 nm in diameter, was optimized. The structural and optical properties of the opals and inverse opals have been studied by field emission scanning electron microscopy and optical reflectivity spectroscopy, in order to assess the relationship between their structure and the photonic properties obtained. By using borosilicate glass substrates hydrophilized with hydrochloric acid, colloidal photonic crystals of good quality have been obtained, with well ordered regions up to ~100 μm2. By monitoring the effective refractive index change with relative humidity of the surrounding atmosphere, using spectroscopic ellipsometry with an environmental chamber, it was concluded that the present photonic crystals are suitable for humidity sensing applications. 相似文献