直流热阴极PCVD法间歇生长模式间歇周期的研究

采用直流热阴极PCVD方法间歇生长模式,在CH4-H2气氛常规制备微米晶金刚石膜的参数条件下,利用人工干预二次形核工艺,研究了间歇周期变化对制备纳米晶金刚石膜的影响.人工干预二次形核是指通过生长温度的周期性改变而诱发二次形核行为,从而实现金刚石膜的纳米晶生长.金刚石膜周期性生长过程分为沉积阶段和干预阶段,沉积阶段主要完成金刚石膜的生长,干预阶段将沉积温度降低到600℃,然后恢复到生长温度,即完成一个生长周期.间歇周期研究主要是考察在不同间歇时间里人工干预诱导二次形核的效果,间歇时间设定为1 min、5 min、10 min、15min、20 min,生长时间设为20 min,总的沉积时间为6 h.采用拉曼光谱仪、SEM和XRD对样品进行了分析,结果表明直流热阴极PCVD方法间歇生长模式,间歇周期的变化,对二次形核的发生有诱导作用,适当选择间歇周期,有利于二次形核基团的生成.     

Carrier Density and Plasma Frequency of Aluminum Nanofilms

In this work, the prerequisite and mode of electromagnetic response of Al nanofilms to electromagnetic wave field was suggested.Reflectance, transmittance in infrared region and carrier density of the films was measured. With the carrier density of the films, the dependence of their plasma frequencies on the film thickness was obtained. On the other hand, the dependence of absorptance on the frequency of electromagnetic wave field was set up by using the measured reflectance and transmittance,which provided plasma frequency-film thickness relation as well. Similarity of both plasma frequency-film thickness relations proved plasma resonance as a mode of electromagnetic response in Al nanofilms.     

基于晶格动力学的纳米薄膜热特性研究

针对分子动力学模拟存在的缺点,提出了基于晶格动力学模拟纳米薄膜热特性的新方法,并用该方法模拟了各种不同厚度的硅和氩纳米薄膜的比热、熔化温度、热膨胀系数和热传导系数等热特性参数。计算结果表明纳米薄膜具有与宏观晶体不同的热特性,并且呈现随纳米薄膜厚度变化的尺寸效应:纳米薄膜越薄,则熔化温度越低、比热越大、面向热膨胀系数越大、法向热传导系数越小;当纳米薄膜厚度远小于相应的宏观晶体的声子平均自由程时,法向热传导系数远小于相应的宏观晶体的热传导系数,并与纳米薄膜厚度成正比。     

Rapid Assembly of Large Scale Transparent Circuit Arrays Using PDMS Nanofilm Shaped Coffee Ring

Rapid and precise assembly of functional nanoparticles into well‐defined structures in large scale is motivated by broad fields. In this study, large‐scale transparent conductive circuit arrays are rapidly self‐assembled by simply pipetting a gold nanoparticles suspension onto a PDMS nanofilm patterned substrate with distinct hydrophilic/hydrophobic areas. The solution firstly self‐confines into predefined hydrophilic geometries, followed by assembly of nanoparticles into well‐defined circuits with 1D patterns by coffee ring effect. Submicrometer height and submicrometer‐ to micrometer‐width circuit arrays with various shapes are precisely generated by varying the PDMS nanofilm patterns. Thousands of circuits with different geometries are self‐assembled simultaneously within 1 min. The conductive circuits show good optical transparency up to 95%. After being transferred into PDMS elastomer sheet by encapsulating, the circuits remain highly conductive during bending and stretching. With the advantages of high‐throughput, equipment‐free, scalability, and precise control, this technique will open an avenue for fabricating large‐scale functional materials for applications in electronics, optoelectronics, and healthcare devices.     

Bilayered nanofilm of polypyrrole and poly(DMcT) for high-performance battery cathodes

Bilayered nanofilm electrodes made of polypyrrole (Ppy) and poly-2,5-dimercapto-1,3,4-thiadiazole (poly-DMcT) are produced by electrochemical means onto a carbon-fiber substrate, with the goal of preventing the loss of the electroactive mass of the disulfide and improving the electrode stability during the charge/discharge cycling process. Lightweight and high surface area composites are obtained by potentiostatically depositing a nanometric layer of Ppy onto a carbon fiber piece already supporting a layer of a potentiodynamically obtained poly(DMcT) film. The growth charge/mass ratio for the bilayered polymeric electrode is optimized, leading to a high electrochemical performance cathode with a stable specific capacity of ∼320 mA h g⁻¹ after 100 cycles.     

Ag/BiOCl复合纳米薄膜的合成及光催化性能研究

研究了贵金属Ag修饰对新型半导体BiOCl薄膜材料光催化性能的影响.采用溶胶-凝胶浸渍提拉法先在ITO玻璃上制备了BiOCl薄膜.以其为基底用磁控溅射方法沉积少量的Ag制备Ag/BiOCl复合纳米薄膜.分别研究了不同沉积时间和溅射气压,以及后处理温度下获得的Ag/BiOCl薄膜对罗丹明B(Rh B)染料在紫外光下的光催化降解活性.结果发现适量的Ag修饰能够提高BiOCl薄膜的光催化活性.通过实验探索,当制备金属Ag的优化参数为溅射压强1 Pa,溅射时间1 s,后处理温度200℃,时间1h时获得的Ag/BiOCl复合纳米薄膜具有最好的光催化性能.用XRD,SEM,UV-Vis光谱等测试方法对其结构、形貌、光谱吸收性等进行了测量分析.进一步探讨了适量贵金属沉积对BiOCl薄膜光催化活性提高的可能原因,杂质能级形成的肖特基势垒对电子有捕获陷阱作用从而增加电子-空穴对的分离,同时利于光生载流子的重新分布.     

溶胶-凝胶工艺制备SrTiO3纳米薄膜的研究

采用溶胶-凝胶方法,以醋酸锶、钛酸四丁酯为前驱体,乙酰丙酮为螯合剂,乙二醇甲醚为溶剂,乙酸为助溶剂和催化剂制备溶胶,用旋涂法在Si(100)衬底上制备出了具有典型钙钛矿型结构的SrTiO3纳米薄膜.用XRD、AFM、SEM和椭圆偏光仪等手段分析了薄膜的性能,结果显示薄膜的表面均匀、无裂纹、厚度20～30nm,折射率1.75～1.85,晶粒度35～60nm,表面平均粗糙度RMS为3.4～3.8 nm,晶粒形貌呈类圆锥形态.     

有序介孔纳米膜的形成机理及在电池中的应用展望

阐述目前制备有序介孔薄膜所用的模板剂(离子型和非离子型表面活性剂)制备介孔薄膜的研究进展,并且就有关现今粉体介孔材料与有序介孔纳米薄膜的形成条件、制备机理的研究方法进行总结,最后展望有序介孔结构薄膜材料在电池器件领域中潜在的应用价值.     

累托石/海藻酸钠插层纳米复合膜的制备与性能

采用水溶液法制备了钠化累托石(Na+REC)与海藻酸钠(SA)插层纳米复合膜(Na+REC/SA)。以红外光谱(IR)、X射线衍射(XRD)分析了复合膜的分子结构,通过电镜扫描(SEM)及原子力显微镜(AFM)观察了复合膜的相貌结构,研究了复合膜的热性能及力学性能。结果表明,Na+REC在添加量较少时可与SA形成插层型纳米复合膜,该复合膜与纯SA膜相比,具有较高的拉伸强度、断裂伸长率及热稳定性。在Na+REC添加2%时,复合膜的拉伸强度、断裂伸长率及热稳定性最高,与纯SA膜相比,拉伸强度提高58.7%,断裂伸长率提高100%,10%失重率时对应的热分解温度提高了115℃,40%失重率时提高了185℃。     

纳米合金薄膜Ni（B）的结构和磁学性质

本文作者用化学沉积法制备了纳米合金薄膜Ni100-xBx(x=1.61,1.95,2.13,2.40,3.02,3.90,6.70,17.3,22.60)系列样品。利用X－射线衍射结构分析方法测量了沉积状态样品和经过热磁处理后样品的结构与颗粒度。利用振动样品磁强计测量了热磁处理前后的磁学参数以及它们随B含量的变化。对部分样品还用超导量子干涉仪测量了低温下的磁滞回线。