2-氨基苯硫酚NIR-SERS光谱及其在纳米银表面吸附行为分析

本文采用静电自组装的方法制备了二维纳米银膜。UV-vis吸收光谱显示其等离子体共振吸收带位于400+900nm的光谱范围,延伸到了近红外区,可以较好的匹配785nm的近红外激发光源。以该纳米银膜为基底,对2-氨基苯硫酚(2-ATP)分子进行了近红外表面增强拉曼散射(NIR-SERS)检测,获得了重复性良好的NIR-SERS光谱图。实验表明:以2-ATP为探针分子时,该纳米银膜的NIR-SERS增强因子达到2.19×109。同时,本文采用密度泛函理论(DFT),以B3LYP/6-31G为基函数,对2-ATP分子进行结构优化和普通拉曼光谱(NR)计算,发现理论值和实验值吻合较好。此外,对2-ATP的NIR-SERS谱带进行了归属分析,发现当2-ATP分子在纳米银表面吸附时,是以-SH基团吸附到银表面,且同时-SH基团会被纳米银氧化。     

胞嘧啶核苷在纳米银膜上的NIR-SERS光谱检测

采用一种高活性的纳米银膜作为表面增强拉曼散射(SERS)基底,以近红外激光(785 nm)作为激发光源,对胞嘧啶核苷(胞苷)水溶液(10-2～10-8 mol·L-1)进行了近红外表面增强拉曼散射(NIR-SERS)光谱检测。实验结果表明,当胞苷水溶液浓度等于或低于10-7 mol · L-1时,可在300～2 000 cm-1范围内获得信噪比较好的NIR-SERS光谱。将胞苷水溶液(10-2～10-5 mol · L-1)分别滴在10片不同的纳米银薄膜上进行检测,结果表明该纳米银膜体现出了较好的光谱重现性。通过对纳米银膜表面形貌进行表征发现聚乙烯醇(PVA)包覆的纳米银颗粒在铝片表面形成“草状”结构。并通过对吸附了胞苷分子的纳米银膜进行紫外-可见光反射光谱检测,发现在800 nm处出现等离子共振峰。因此采用785 nm的近红外激光作为激发光时,该体系能够体现出强烈的表面等离子共振(surface plasmon resonance, SPR)特性。同时采用DFT-B3LYP/6-311G对胞苷分子进行了拉曼光谱计算,计算所采用入射光波长为785 nm,通过计算结果与实验测得的胞苷固体的拉曼光谱对比发现在300～2 000 cm-1范围内两者匹配得较好,进而对其振动进行了归属。最后通过比较胞苷的拉曼光谱和NIR-SERS光谱对胞苷分子在纳米银膜上的可能吸附方式进行了分析。分析结果表明胞苷分子主要为其核糖部分吸附纳米银颗粒上,同时该分子的17NH₂基团可能靠近局域电磁场增强区域。     

基于宽表面等离子体吸收带纳米银膜的制备及其SERS活性研究

在恒温条件下,采用静电自组装技术在玻璃表面制备了一种具有宽等离子吸收带的纳米银膜。使用扫描电镜(SEM)观察其表面形貌发现该纳米银膜表面由粒径为18～200 nm的纳米球组成。同时从紫外可见光谱检测结果发现该纳米银膜在400～850 nm间有较宽的等离子吸收带。分别以强荧光分子(结晶紫)和生物大分子(健康人血清)作为探针分子,在近红外激发光(785 nm)下检测出了质量较好的SERS光谱。同时,分析了该纳米银膜对两种分子检测的重复性。     

片状三角形银纳米颗粒的自组织行为与光学特行

用化学方法制备了一种规则的片状三角形银纳米颗粒,边长为100±10nm,厚度约为30nm.紫外-可见光谱分析表明了三角形银纳米颗粒形貌的完整性.颗粒表面修饰的有机分子,使三角形银纳米颗粒在碳膜上自组织形成二维单层膜,在硅片上形成高取向银膜,该银膜对吡啶分子具有很强的表面增强拉曼散射效应,增强因子可达108.     

片状三角形银纳米颗粒的自组织行为与光学特性

用化学方法制备了一种规则的片状三角形银纳米颗粒，边长为100±10nm，厚度约为30nm.紫外可见光谱分析表明了三角形银纳米颗粒形貌的完整性.颗粒表面修饰的有机分子，使三角形银纳米颗粒在碳膜上自组织形成二维单层膜，在硅片上形成高取向银膜，该银膜对吡啶分子具有很强的表面增强拉曼散射效应，增强因子可达108.     

D-核糖NIR-SERS光谱及其在金纳米棒表面吸附行为分析

本文采用种子生长法、利用双表面修饰剂制备了金纳米棒,其长径比为3.5:1。该金纳米棒的消光光谱显示:利用该方法制备的金纳米棒有两个表面等离子共振(SPR)峰,分别位于540nm和780nm处。其中780nm处的表面等离子共振峰靠近红外光谱区,可以与文中采用的激发光源(785nm激光)较好的匹配,从而有助于实现共振拉曼散射增强效应。本文以D-核糖(D-Ribose)为探测分子,基于金纳米棒进行了近红外表面拉曼散射(NIR-SERS)活性检测,从而获得了光谱重复性良好的NIR-SERS光谱图。同时,采用密度泛函理论(DFT),以B3LYP/6-31G和6-31G/LanL2DZ为基组函数,分别对D-核糖分子以及D-核糖分子与金原子形成的团簇进行结构优化和普通拉曼光谱(NR)计算,发现理论值和实验值符合较好。此外,文中对D-核糖的NIR-SERS谱带进行了分析和归属,发现当D-核糖分子吸附到金纳米粒棒上时,主要是以羟基上的氧原子(O9)吸附在金原子上而形成金属键。     

甲氰菊酯在纳米银膜上的SERS光谱检测

本文将聚乙烯醇(PVA)包覆的纳米银粒子组装在铝片表面形成的纳米银薄膜作为表面增强拉曼散射基底,使用扫描电镜对纳米银膜的表面形貌进行了表征。同时采用近红外激光(785nm)作为激发光对甲氰菊酯的丙酮溶液(10-4~10-7 mol/L)进行了近红外表面增强拉曼散射(NIR-SERS)光谱检测。结果表明该方法对甲氰菊酯的检测极限为10-6 mol/L。最后对甲氰菊酯的NIR-SERS光谱重现性进行了检测,即分别检测了浓度为10-4 mol/L和10-5 mol/L的甲氰菊酯丙酮溶液各6个样品,实验结果表明该纳米银膜在检测甲氰菊酯时体现出了较好的重复性。     

热退火诱导纳米银膜形貌变化对表面等离激元共振特性的影响

采用磁控溅射技术制备并通过不同温度的快速热退火得到了不同表面形貌的纳米银膜。利用XRD,SEM和紫外-可见-近红外透射光谱等技术研究了纳米银膜的结构、表面形貌与光学性质。实验结果表明,随着退火温度的升高,银膜开口面积分数、银岛(纳米粒子)间距增大,长宽比减小,银岛由各向异性的蠕虫状变成各向同性的纳米球;表面等离激元共振带发生连续的蓝移,半高宽变窄。分析表明,纳米银膜的表面等离激元共振特性可以通过热退火诱导的表面形貌变化实现调整。     

基于新型NIR-SERS基底的肝癌血清NIR-SERS光谱研究

基于一种新型、高效、生物兼容性近红外表面增强拉曼散射(NIR-SERS)基底,采用便携式近红外拉曼光谱仪分别对健康人和肝癌病患者的血清进行了NIR-SERS光谱研究.实验发现,健康人与肝癌患者的血清NIR-SERS光谱存在显著差异:1)健康人血清NIR-SERS光谱中位于630、720、812和1578 cm-1附近的...     

基于NIR-SERS技术结合PCA-LDA统计分析肝癌术后恢复状况

采用近红外表面增强拉曼散射(NIR-SERS)光谱技术,基于高效、稳定、低廉的纳米银膜基底检测了25例肝癌患者、25例肝癌术后患者和25例健康人的氧合血红蛋白(Oxy Hb)。对比发现,健康人、肝癌术后患者和肝癌患者的Oxy Hb的NIR-SERS光谱谱峰强度呈现依次下降的趋势,表明从谱峰强度可以初步判断肝癌术后患者恢复情况。利用主成分分析(PCA)结合线性判别分析(LDA)统计方法进行分析,25个肝癌术后患者中8人判别为健康人,其余17人判别为肝癌患者。判别分组与实际情况相符,表明PCA-LDA统计方法可以更准确地判断肝癌术后患者恢复状况。因此,NIR-SERS技术结合PCA-LDA统计方法有望为肝癌术后患者恢复状况的诊断提供一种新的思路和方法。     

Silver nanoplates: controlled preparation, self-assembly, and applications in surface-enhanced Raman scattering

Silver nanoplates were prepared in a dual reduction system with NaBH₄ and sodium citrate both as reducing agents. And then the as-prepared nanoplates could be growing up through multistage growth methodology. The average edge length of Ag nanoplates can be tailored from 40 nm to 260 nm without changing their shape, crystallinity, and the average thickness. Furthermore, the effectiveness of these silver nanoplates as substrates prepared by the silanization self-assembly method toward surface-enhanced Raman scattering (SERS) detection was evaluated by using 4-aminothiophenol (4-ATP) and rhodamine 6G (R6G) as probe molecules. It was found that the enhancement ability of the silver nanoplates film is remarkable lower than that of the spherical silver nanoparticle film. The reason is attributed to the electromagnetic mechanism and chemical mechanism. This work will be of great significance in understanding the SERS enhancement mechanism and in the fabrication of nanoparticle films for biosensing.     

基于NIR-SERS技术结合统计分析肺癌氧合血红蛋白

基于新型、高效、生物兼容性近红外表面增强拉曼散射(NIR-SERS)基底,采用共焦光路设计的便携式拉曼光谱仪,对25例肺癌患者和25例健康人的氧合血红蛋白进行NIR-SERS光谱检测,再对两者NIR-SERS光谱的谱峰强度和谱峰位置进行分析研究。发现两者的NIR-SERS光谱的谱峰强度在一定区域存在较明显的差异性,在473,816和1 583 cm-1处健康人的光谱的谱峰强度比肺癌患者要大,健康人氧合血红蛋白平均NIR-SERS光谱在1 208和1 425 cm-1谱峰处时,肺癌患者分别蓝移到1 212和1 432 cm-1,健康人氧合血红蛋白平均NIR-SERS光谱在1 583 cm-1的谱峰处,肺癌患者红移到1 579 cm-1。采用主成分(PCA)分析和独立变量T检验统计分析方法得出NIR-SERS光谱在主成分得分PC3,PC4和PC9处具有显著差异,并通过PCA得分二维、三维散点图可以将健康人和肺癌患者区分,诊断的特异性为88%,灵敏度为80%,总判别正确率为84%。通过谱峰归属分析,两者的NIR-SERS光谱存在显著差异与氧合血红蛋白吡咯环和乙烯基团(C_aC_m)的振动有关。该研究为肺癌的SERS光谱技术诊断提供了实验依据,NIR-SERS技术有望发展成为一种新型的临床辅助诊断工具。     

Synthesis and optical characterization of nanocrystalline CdTe thin films

From several years the study of binary compounds has been intensified in order to find new materials for solar photocells. The development of thin film solar cells is an active area of research at this time. Much attention has been paid to the development of low cost, high efficiency thin film solar cells. CdTe is one of the suitable candidates for the production of thin film solar cells due to its ideal band gap, high absorption coefficient. The present work deals with thickness dependent study of CdTe thin films. Nanocrystalline CdTe bulk powder was synthesized by wet chemical route at pH≈11.2 using cadmium chloride and potassium telluride as starting materials. The product sample was characterized by transmission electron microscope, X-ray diffraction and scanning electron microscope. The structural characteristics studied by X-ray diffraction showed that the films are polycrystalline in nature. CdTe thin films with thickness 40, 60, 80 and 100 nm were prepared on glass substrates by using thermal evaporation onto glass substrate under a vacuum of 10⁻⁶ Torr. The optical constants (absorption coefficient, optical band gap, refractive index, extinction coefficient, real and imaginary part of dielectric constant) of CdTe thin films was studied as a function of photon energy in the wavelength region 400–2000 nm. Analysis of the optical absorption data shows that the rule of direct transitions predominates. It has been found that the absorption coefficient, refractive index (n) and extinction coefficient (k) decreases while the values of optical band gap increase with an increase in thickness from 40 to 100 nm, which can be explained qualitatively by a thickness dependence of the grain size through decrease in grain boundary barrier height with grain size.     

Fabrication Techniques and Characteristics of Ultra-Thin Optical Polarizing Films Using Gold Island Films

Fabrication techniques of ultra-thin optical polarizing films using gold island films have been investigated for the near-infrared region. The polarizing films are fabricated by stretching the periodic multilayers consisting of gold island layers and glass layers. We have experimentally investigated the optimum fabricating conditions necessary to induce large optical anisotropy into the gold island layers and have formed submicrometer-thick polarizing films with an extinction ratio of ≥20 dB in a near-infrared region longer than 800 nm. These polarizing films could be useful micro-polarizers for fiber-embedded in-line optical devices, micro-optics, and hybrid integrated optics.     

抗癌新药安吖啶的近红外拉曼光谱及近红外表面增强拉曼光谱的研究

采用近红外表面增强拉曼光谱技术对抗癌新药安吖啶的结构进行了研究。     

Optical properties of dye-doped zirconia films by spectroscopic ellipsometry

The optical properties of zirconia films doped with rhodamine 6G and oxazine 725 by the sol-gel process were investigated using spectroscopic ellipsometry (SE). Accurate refractive index n and the extinction coefficient k were determined using a three-oscillator classical Lorentz model in the wavelength range of 300-800 nm. The derived refractive index of dye-doped films exhibited anomalous dispersion in the absorption region. Wavelength tunable output lasing action yellow and near-infrared wavelength region was achieved by DFB configuration using zirconia films doped with R6G and oxazine 725.     

Optically tuned dielectric characteristics of SrTiO_3/Si thin film in the terahertz range

Active control of the optical parameters in strontium titanate(SrTiO_3, STO) thin films is highly desirable for tunable terahertz(THz) integrated devices such as filters, phase modulators, and electro-optical devices. In this work, optically tuned dielectric parameters of a STO thin film epitaxially grown on a silicon wafer were characterized in the THz region with an 800 nm laser pump-THz detection system. The refractive index, extinction coefficient, and complex dielectric constant of the STO thin film were calculated using thin-film parameter extraction. Owing to carrier transportation and soft-mode oscillation, the above optical parameters changed notably with the pump power of the external laser. This study is of great significance for rapid and non-contact THz phase-modulation technology and may serve as a powerful tool to tune the dielectric properties of the STO thin films.     

激光致晶态Ag11In12Te26Sb51相变介质光学常数的研究

研究了结晶度对Ag11In12 Te2 6Sb51相变薄膜光学常数的影响。用初始化仪使相变薄膜晶化 ,改变晶化参量得到不同的结晶度 ,当转速固定时 ,随激光功率的增加 ,折射率基本随之减小 ,消光系数先是增大 ,而后减小 ;当激光功率固定时 ,随转速的增大 ,折射率也随之增大 ,消光系数也是先增大后减小。非晶态与晶态间的变换、薄膜微结构的变化 (包括晶型的转变和原子间键合状态的变化 )以及薄膜内残余应力是影响Ag11In12 Te2 6Sb51相变薄膜复数折射率的主要原因。测量了单层膜的透过率和CD RW相变光盘中Ag11In12 Te2 6Sb51薄膜非晶态和晶态的反射率