有序金纳米棒阵列的超分辨成像

显微成像技术受限于光学成像系统的衍射极限,无法分辨亚波长尺度的结构。通过饱和散射抑制成像技术已经实现了单个纳米颗粒的超分辨成像,但是涉及到纳米颗粒集合,需要考虑纳米颗粒间的耦合作用。利用超越衍射极限的双光束方法,可以在有序金纳米棒阵列上实现远场超分辨光学成像。本文设计了纳米棒长径比为2的5×5金纳米棒阵列,通过矢量光场理论和热扩散理论计算了金纳米棒阵列在连续波激光下的热分布,并模拟了双光束激光即脉冲激发光和连续波抑制光下的散射成像。仿真结果显示,连续波激光能够有效抑制金纳米棒阵列对脉冲激光的散射,双光束方法实现了80 nm横向特征尺寸的超分辨成像。     

硫掺杂纳米二氧化钛的水热合成及其光催化性能研究

以钛酸四丁酯为前驱物,无水乙醇为溶剂,盐酸为抑制剂,水作反应剂,用硫脲为掺杂剂,采用水热法制得二氧化钛纳米粉体,并对样品进行硫离子掺杂的研究。通过将掺杂的二氧化钛粉末在可见光下进行光降解试验,研究了非金属硫离子的掺杂规律。试验结果表明,掺杂后的样品光催化降解能力得到了提高,存在最优的掺杂比例,并且在可见光下产生了较好的降解效果。     

水热法合成棒束状纳米CeO_2粉体及其催化性能

在醇-水体系中以P123为模板、硝酸铈和草酸为原料,利用水热法制备了棒束状纳米CeO2粉体,研究了反应温度、硝酸铈与草酸的物质的量比(nCH)、溶液pH以及反应时间对CeO2粉体颗粒的影响,确定了制备棒束状纳米CeO2粉体的最佳工艺参数;将最佳工艺参数下制得的CeO2对酸性品红溶液进行催化降解试验,并与块状CeO2催化降解结果进行对比。结果表明:制备棒束状纳米CeO2的最佳工艺参数为200℃、nCH=2∶3、pH=1、反应时间360 min;在此最佳工艺参数下制备的棒束状纳米CeO2对酸性品红溶液的催化活性比普通块状CeO2的大大提高。     

Ga掺杂ZnO微米棒紫外光探测器的制备与特性

为了获得高性能和低成本的氧化锌(ZnO)基紫外光探测器,使用Ga掺杂ZnO(ZnO∶Ga)作为光敏层,采用水热法合成了不同Ga掺杂浓度ZnO∶Ga微米棒,Ga与Zn的原子比分别为0%(未掺杂),0.5%,1%,2%和4%。使用X射线衍射仪(XRD)测试所有样品的晶体结构,发现它们都为六方纤锌矿结构的ZnO。采用扫描电子显微镜(SEM)观察它们的形貌,都呈现棒状结构。进一步,制备叉指图案氟掺杂的氧化锡(FTO)导电玻璃基底,将不同Ga掺杂浓度ZnO∶Ga微米棒分别涂覆在FTO上,得到5种简单结构的紫外光探测器,系统研究了它们的性能。结果表明：所有ZnO∶Ga微米棒紫外光探测器对365 nm紫外光表现出良好的响应。其中,1%Ga掺杂ZnO∶Ga微米棒紫外光探测器性能最佳,经计算,在365 nm波长处,它的响应度、增益和比探测率分别为13.13 A/W (5 V),44.63 (5 V),3.31×10¹² Jones,响应时间和衰减时间分别为12.3 s和36.4 s。说明在ZnO微米棒中进行合适Ga掺杂能有效提高紫外光探测器的性能。该研究有助于基于ZnO∶Ga材料的...     

Si基ZnO纳米结构异质结光伏器件的光电性能研究

采用化学气相沉积的方法在p型Si衬底上生长了n型ZnO纳米棒并在此基础上制备了Si基ZnO纳米结构异质结光伏电池。器件的平均反射率约为5%,电池具有良好的整流特性。同时发现取向较好的ZnO纳米结构的电池具有好的转换效率,最好样品的转换效率为2.6%,填充因子为45%。     

不同球磨时间铁掺杂TiO2粉的物相组成和磁性

利用高能球磨法球磨不同时间得到不同铁掺杂量的TiO2粉，并利用电感耦合等离子发射光谱仪、X射线衍射仪、拉曼光谱仪和振动样品磁强计对粉体的物相组成和磁性能进行了分析。结果表明：球磨不仅使铁固溶进入TiO2晶格中，还诱发了TiO2从锐钛矿相向S相和金红石相的转变，粉体中未发现铁及铁的氧化物；所有粉体都表现出室温铁磁性，球磨...     

掺杂CdSe纳米晶粒的玻璃纤维传感器在温度测量上的应用

报导了掺杂CdSe纳米晶粒的磷酸盐玻璃作为敏感元件的温度纤维传感器,在低于玻璃的退火温度（＜370℃）时,这种玻璃表现出可逆的温度感应吸收的漂移,利用反射光栅和双池光电二极管的双波长探测方案,可以消除强度相关传感器中各种信号损耗的影响,在－20到＋120℃温度范围内测试传感器样机,对温度变量显示了一个线性响应。     

油溶性氟化镧纳米棒的制备及其摩擦学性能研究

利用超声波辅助处理,在乙醇-水体系中,以二辛基二硫代磷酸双(β-)羟乙基十八胺盐为表面修饰剂制备了表面修饰氟化镧纳米棒,通过相转移法制得油溶性纳米氟化镧添加剂.通过X射线衍射仪(XRD)、透射电镜(TEM)及热重仪(TG)表征了表面修饰氟化镧纳米棒的结构及形貌,利用离心沉降法和升温法结合研究了添加剂中纳米氟化镧在500SN基础油中的分散稳定性和高温稳定性,利用四球机考察了纳米氟化镧的摩擦学性能,并通过SEM和AES分析了钢球磨斑表面.结果表明:氟化镧纳米棒直径在4～7 nm之间,长度为20～30 nm;氟化镧纳米棒在500SN基础油中具有良好的分散稳定性,并可使基础油的最大无卡咬负荷值增加了109.61%,磨斑直径降低39.13%;AES结果表明,氟化镧沉积在磨斑表面形成一层复合膜,并且渗透入磨斑的亚表面,共同提高基础油的摩擦学性能.     

Ag掺杂对TiO2纳米薄膜结构及摩擦学性能的影响

采用溶胶凝胶法在普通载玻片上制备了TiO2和Ag/TiO2纳米结构薄膜,利用X射线衍射仪(XRD)、X光电子能谱(XPS)、原子力显微镜(AFM)及UMT-2摩擦试验机,考察了Ag掺杂量对薄膜组成结构、表面形貌及摩擦学性能的影响。实验结果表明,Ag掺杂量对TiO2薄膜表面形貌和减摩抗磨性能产生重要影响,低掺杂时Ag自润滑性能对薄膜摩擦性能的增强作用占主导,而高掺杂时其对薄膜的影响主要表现为恶化表面,从而导致摩擦性能下降。本研究测试条件下,掺杂量为5.0%(摩尔分数)时具有最佳的耐磨寿命和最低的摩擦因数。     

硅纳米锥阵列结构参数对抗反射性能研究

为得到太阳能硅基板上不同尺寸纳米锥阵列结构对抗反射性能的影响规律,采用时域有限差分法进行仿真分析.在已完成的3个模型基础上,以0.3μm～1.2μm光源波段内的平均反射率作为目标函数,对硅纳米锥阵列结构的高度、周期以及上、下端面直径进行研究分析,得到了硅纳米锥阵列结构参数变化对平均反射率的影响规律.根据影响规律进行参数...     

Nanoscale electrical properties of ZnO nanorods grown by chemical bath deposition

Well‐aligned zinc oxide nanorod arrays (ZNAs) synthesized using chemical bath deposition were fabricated on a gallium‐doped zinc oxide substrate, and the effects of varying the precursor concentrations on the growth and nanoscale electrical properties of the ZNAs were investigated. The as‐synthesized ZNAs were characterized using field‐emission scanning electron microscopy (FESEM), atomic force microscopy (AFM), conducting atomic force microscopy (CAFM), and scanning surface potential microscopy (SSPM). The FESEM and AFM images show that the growth rate in terms of length and diameter is highly sensitive to the precursor concentration. CAFM and SSPM analyses indicate that when concentrations of both the zinc acetate and hexamethylenetetramine solutions were 30 mM, the coverage percentages of the recordable and conducting regions on the ZNA surface were 48.3% and 0.9%, which is suitable for application in resistive random access memory devices.     

应用L-MBE方法制备ZnO薄膜的结构和光学特性

用激光分子束外延(Laser Molecular Beam Epitaxy,L-MBE)设备在p型Si(111)衬底上制备了不同衬底温度和不同氧压的ZnO薄膜,用X射线衍射仪(XRD)和原子力显微镜(AFM)分别对薄膜的结构和形貌进行了分析,用He-Cd激光(325nm)激发的光致发光测试系统对薄膜进行了荧光光谱分析。研究发现,在衬底温度为400℃,氧压1Pa左右所制备的ZnO薄膜表面比较均匀致密,晶粒生长较充分,有较高的结晶质量和发光强度。ZnO薄膜的近带边发射与薄膜的结晶质量和化学配比均有关系。     

Al、Sn掺杂对于ZnO薄膜微结构及光学特性的影响

采用真空电子束蒸发金属薄膜及后续热氧化技术在石英衬底上分别制备出了ZnO、Al∶ZnO以及Sn∶ZnO薄膜。通过X射线衍射仪(XRD),紫外-可见分光光度计和原子力显微镜(AFM)等分析仪器对比研究了Al、Sn掺杂对ZnO薄膜结晶质量、光学性质及表面形貌的影响。测试结果表明,Al、Sn掺杂可以使薄膜结晶质量得到提高,薄膜应力部分释放,薄膜表面的粗糙度也相应增加,掺杂对薄膜光学带隙的影响在一定程度取决于金属薄膜的氧化程度,氧化充分可以使光学带隙变宽,反之则变窄。     

ZnO纳米线的光致发光性及拉曼散射性能

利用物理热蒸发法通过控制载气流量和氧气流量制备出具有倒V字形尖端的ZnO纳米线,利用荧光光谱仪、拉曼光谱仪对ZnO纳米线的光致发光性能和拉曼散射性能进行了测试.结果表明:与其它形状的ZnO纳米线的光致发光性能不同,该ZnO纳米线在423～458 nm区域有二个宽频带强蓝光发射,在527 nm处出现一个非常弱的绿光发射,没有发现紫外光发射;相对于ZnO纳米粉,ZnO纳米线的拉曼光谱峰发生约3 cm-1红移,主要来源于光子限制效应.     

Effect of Ni and Al doping on structural,optical, and CO2 gas sensing properties of 1D ZnO nanorods produced by hydrothermal method

In the present study, the one-dimensional ZnO nanorod structures are produced within the different nickel and aluminum molecular weight ratios of 0–7% using the hydrothermal method. It is found that the aluminum (Al) and nickel (Ni) impurities with different ionic radius, chemical valence, and electron configurations of outer shell cause to vary the fundamental characteristic features including the crystallinity quality, crystallite size, surface morphology, nanorod diameter, optical absorbance, energy band gap, resistance, gas response, and gas sensing properties. The structural analyses performed by powder X-ray diffraction (XRD) and scanning electron microscopy (SEM) indicate that the samples are found to crystallize in the hexagonal wurtzite structure. The presence of optimum nickel and aluminum in the crystal system improves considerably the crystallinity quality and surface morphology. Additionally, the combination of electron dispersive X-ray (EDX) and XRD results declare that the Ni and Al impurities incorporate successfully into the ZnO crystal structure. Moreover, the diameters of nanorod structures in 1D orientation are determined to be 80 nm or below. The hexagonal wurtzite-type ZnO nanorod structure prepared by 5% Ni has more space between the nanorods and thus presents higher response to the CO₂ detection. Further, the optical absorbance spectra display that the band gap value is observed to decrease regularly with the increment in the doping level as a result of band shrinkage effect depending on the enhancement of mobile hole carrier concentrations in the crystal structure. In other words, the doping mechanism leads to vary the homogeneities in the interfacial charges, nanorod diameters, ZnO oxide layer composition and thickness. The last test conducted in this study is responsible for the determination of CO₂ gas sensing levels. The obtained gas sensing results are further compared with each other and literature findings. It is observed that 5% Ni-doped sample provides more successful results than other samples in the sensing CO₂ gas at the different concentrations. All in all, the paper establishing a strong methodology between doping mechanism and change in the fundamental characteristic features of hexagonal wurtzite-type ZnO with the aid of advanced microscopy techniques will become pioneering research to answer key questions in materials sciences and electronic research.     

纳米ZnO填充PTFE复合材料的力学及摩擦学性能

通过机械搅拌和超声分散制备纳米ZnO填充PTFE复合材料,研究纳米ZnO填充量对复合材料力学及摩擦磨损性能的影响。结果表明:当ZnO质量分数小于3%时,复合材料的拉伸强度与纯PTFE相比略有增高;复合材料的密度、硬度、摩擦因数随ZnO填充量的增加而逐渐增大;当ZnO填充质量分数为1%～3%时,复合材料的磨耗量大幅下降,但若继续增加ZnO填充量,复合材料的磨耗量却变化不大。     

ZnO microrods to nanowalled microtubes: optimization using simple fluorescence microscopy and enhanced photocatalytic properties

ZnO microtubes (MTs) of nanoscale wall thickness were prepared by synthesis of ZnO microrods (MRs) followed by etching the MRs to form MTs. ZnO MRs were synthesized by a simple solution growth method using zinc chloride and hexamine as precursors. Using KOH, ZnO MRs are etched into ZnO MTs. ZnO MTs were characterized by fluorescence microscopy (FM), X‐ray diffraction, scanning electron microscopy, UV‐Vis and photoluminescence spectroscopy. ZnO MTs have a diameter of ～600 nm, wall thickness of 30–40 nm and length of ～7 μm. The influence of the KOH concentration and etching time on ZnO MRs for the formation of the ZnO MTs were studied. The formation of nanowalled ZnO tubes from ZnO MRs is optimized by simple and inexpensive FM imaging. FM was utilized as a tool to observe the changes in optical properties on change in morphology from ZnO MRs to MTs. FM images reveal that at low KOH concentration (0.125 M) the tubes were not completely etched whereas at higher concentration (0.375 M) the tube walls were damaged. Etchant concentration (0.125 M) and etching time of 12 h were found to be the optimized parameters for the realization of ZnO MTs using FM analysis. ZnO MTs were tested as the catalyst for the photodegradation of the methylene blue dye. The result shows that the photodegradation efficiency of the tubes is twice as fast as compared to that of rods.     

不同形貌的氧化锌生长机制及光学性能比较

采用化学气相沉积的方法,通过调控压强和蒸发温度等条件,制备得到了梳状、超长悬臂和螺旋等形状各异的 ZnO 纳米材料,并对 ZnO 纳米材料的生长机制和动力学特性进行了初步探讨。利用X 射线衍射（XRD）和扫描电子显微镜（SEM）对样品的结构、形貌和光致发光光谱进行了分析。     

Al2O3掺杂ZnO纳米粉体的制备及气敏特性研究

采用sol-gel法制备了w(Al2O3)为2%～4%的Al2O3-ZnO纳米粉体,利用XRD和SEM等测试手段分析了粉体的微观结构.研究了Zn2+浓度、pH值和清洗对粉体制备的影响.采用静态配气法测试了由所制粉体制成的气敏元件对丙酮、乙醇、甲醇等气体的气敏性能.结果表明:用该法得到的粉体材料颗粒粒径小,工作温度为160℃时,由w(Al2O3)为3%的粉体在700℃退火制得的气敏元件对体积分数为40%的丙酮的灵敏度最高可达到7 779,响应-恢复时间均为1S.