排序方式: 共有13条查询结果,搜索用时 31 毫秒
1.
通过柠檬酸钠还原银离子,以银纳米粒子为种子,在室温下制备出平均厚度约为5nm,尺寸40到500nm可调的三角形银纳米片。通过种子调停法可实现银纳米盘的面内偶极表面等离子体共振峰(SPR)从最初的520nm红移至1100nm。通过控制实验参数能够很好地理解其生长机制。柠檬酸根离子和增加到生长液里面的银纳米种子是2个重要的参数,可以控制银纳米盘的大小却不改变银纳米盘的厚度以及晶面结构。采用PVP作为包覆剂,其作用机理还不是很清楚,需要进一步的研究。 相似文献
2.
以经硅烷化后的玻璃片为基底,吸附三角形银纳米种子,采用柠檬酸钠为还原剂,在室温下还原硝酸银,制备出基底表面具有三角形银纳米粒子聚集结构的材料。应用透射电镜、扫描电镜、X射线衍射仪、吸收和荧光光谱对产物的结构和性质进行表征。结果表明:随着生长液体积的增加,基片上三角形银纳米盘的平均粒径长大约为300nm,且基底上出现了双层粒子堆叠;基底上纳米粒子的吸收光谱中出现了由银粒子的表面等离子体激元偶极子耦合引发的强烈吸收峰,耦合峰在600~800nm波段内移动;在215nm紫外光的激发下,基底上纳米粒子的荧光光谱在400nm处出现发射峰,荧光光谱的发光强度随着基底上粒子平均尺度增加而减弱。 相似文献
3.
Silver nano-particles with average diameter of about 60 nm were compacted in a high-strength mold under different pressures
at 523 K to produce nano-structured Ag solid materials. The structure and characteristic of the nano-structured Ag solid materials
(NSS-Ag) were studied using X-ray diffraction (XRD), scanning electron microscope (SEM) and Raman spectrometer. The NSS-Ag
could be used as highly efficient surface-enhanced Raman scattering (SERS) active substrates. The common probe molecules Rhodamine
6G (R6G, 1×10−10 mol/L) were used to test the SERS activity on these substrates at very low concentrations. It is found that the SERS enhancement
ability is dependent on the density of NSS-Ag. When the relative density of NSS-Ag is 83.87%, the materials reveal great SERS
signal. 相似文献
4.
采用自悬浮定向流法制备单相Ag2Al金属间化合物纳米颗粒及Ag和Al纳米颗粒;利用透射电镜、X射线衍射、X射线光电子能谱分析、电感耦合等离子体发射光谱等对纳米Ag2Al微晶的形貌、粒度、相组成、成分及微结构进行表征。研究表明:所制备的金属间化合物纳米粒子为球形的六边形结构,其平均粒径为33μm,样品中Ag和Al的摩尔比非常接近标准配比2:1,颗粒由单相的Ag2Al组成。对放置在空气中的Ag2Al纳米颗粒表面成分进行分析,XPS测试结果表明:在Ag2Al微晶表面形成了一层很薄的氧化物膜,可能是铝的氧化物或银铝氧化物。实验证实,通过控制气相反应的工艺条件可以制备出粒径很小的单相Ag2Al纳米晶。 相似文献
5.
6.
以双还原剂法制备的单晶三角形银纳米盘为模板,在室温HAuCl4溶液中发生多轮置换反应,制备Au-Ag三角纳米环材料。采用TEM、EDX和XRD等检测手段表征反应阶段产物的形貌、组成以及晶体结构。TEM、EDX和电子衍射谱证实Au置换了Ag。反应7轮后纳米盘的面内偶极表面等离子体共振峰从初始的700nm逐步红移到1100nm,形貌从实心盘状逐渐变为空心纳米环。改变每轮加入的HAuCl4量即可精细调节面内偶极峰的红移步进量。通过采用SERS光谱检测方法,随着多步置换反应的进行,提出了一个可行的形成机理机制。 相似文献
7.
采用离散偶极子近似方法(discrete dipoleapproximation,简称DDA)从理论上对玻璃基底上不同粒径的Au纳米粒子结构阵列的消光光谱以及消光峰与纳米粒子粒径的关系进行了研究。计算结果显示玻璃基底上的Au纳米粒子结构阵列的消光谱中出现明显区别于Au单体纳米粒子的共振峰,玻璃基底上的Au纳米粒子结构阵列的消光性质与单体纳米粒子的粒径密切相关,随着纳米粒径的增大表面等离子体共振吸收峰出现明显红移,并且在粒径>40nm时出现多峰吸收现象。计算结果与实验结果基本一致。给出玻璃基底上的Au纳米粒子结构阵列的共振吸收峰随单体纳米粒子粒径变化的关系图。对Au纳米结构阵列的吸收机制进行系统的理论分析。 相似文献
8.
9.
10.
Nanoporous copper with nano-scale pore size was synthesized by dealloying Mn-Cu precursor alloy using a free corrosion method.
The effects of heat treatment of Mn-Cu precursors on alloy phase, morphology and composition of the resultant nanoporous copper
were investigated. It is revealed that the compositions distribute homogeneously in the bulk Mn-Cu precursors, which consequently
results in a more fully dealloying for forming nanoporous copper. The alloy phase changes from Cu0.49Mn0.51 and Cu0.21Mn0.79 of non-thermally treated precursor to Cu0.33Mn0.67 of heat treated alloy. The residual Mn content in nanoporous copper is decreased from 12.97% to 2.04% (molar fraction) made
from the precursor without and with 95 h heat treatment. The typical pore shape of nanoporous copper prepared by dealloying
the precursor without the heat treatment is divided into two different zones: the uniform bi-continuous structure zone and
the blurry or no pore structure zone. Nanoporous copper is of a uniform sponge-like morphology made from the heat-treated
precursor, and the average ligament diameter is 40 nm, far smaller than that from the non-thermally treated precursor, in
which the average ligament diameter is estimated to be about 70 nm. 相似文献