金MPC掺杂琼脂-明胶复合泡沫的均匀性研究

 采用表面包覆水溶性硫醇单分子层的金团簇（MPC）对琼脂-明胶复合泡沫进行掺杂。研究表明,掺杂泡沫轴向密度均匀，金MPC粒径小，不聚焦，在泡沫中分散良好，掺杂对泡沫微观形貌没有明显影响。当掺杂泡沫密度低至5.8 mg/cmcm³，、掺杂质量分数高达30%时，金MPC在复合泡沫中不发生沉降或聚集。以水作溶剂，成功制得密度小于10 mg/cm³，孔径小于100 mm的金MPC掺杂琼脂-明胶泡沫靶材料。     

γ辐照对掺Er硅酸盐玻璃吸收和发光特性的影响

用传统的高温熔融法熔制了一系列掺Er硅酸盐玻璃, 并测试了这些样品经5 kGy γ 射线辐照前后紫外至近红外的吸收和荧光光谱. 实验结果表明, 辐致暗化效应使得玻璃材料中形成了大量色心, 导致在400 nm附近出现强吸收带, 其尾端延伸至近红外区. 辐照产生的新能带增加了基质与Er³⁺ 特定能级(如²H_11/2, ⁴S_3/2及⁴F_9/2等) 之间的能量传递, 从而使辐照后的样品荧光寿命减小, 且在相同激发条件下荧光强度下降. 室温下辐照样品在荧光测试过程中出现了漂白现象.     

Mg，Ti共掺Al2O3透明多晶陶瓷光谱性能研究

采用传统无压烧结工艺制备Mg，Ti共掺透明氧化铝陶瓷，测定了其吸收光谱、荧光光谱和激发光谱，结果表明，由于Mg²⁺的电荷补偿，当Ti掺入量较小时，Ti主要以Ti⁴⁺形式存在，(Mg，Ti):Al₂O₃透明陶瓷只在250nm的紫外波段有吸收峰，为O^2-→Ti⁴⁺的电荷转移跃迁产生的吸收，并产生Ti⁴⁺离子在280—290nm和410—420nm的荧光发射峰     

苯并咪唑的三维荧光光谱与三维室温磷光光谱

测量了浓度为1×10^-4mol/L苯并咪唑水溶液的三维荧光光谱,三维室温磷光光谱和紫外/可见吸收光谱,还测量了苯并咪唑固体紫外/可见吸收光谱对化合物的荧光和室温磷光进行了分析、比较,发现苯并咪唑在290nm、580nm和870nm区域均有强而丰富的荧光谱线,而室温磷光谱线(RTP)单一地出现在290nm区域,且强度很小;同时还讨论了苯并咪唑的升频转换荧光现象.     

LiKGdF5:Er,Dy单晶的UV、VUV光谱和量子剪裁

报道了LiKGdF₅:Er(2%),Dy(0.4%)单晶在紫外激光和同步辐射真空紫外光激发下的光谱特性,讨论了在不同激光(He-Cd激光,325nm;3倍频的YAG:Nd激光,355nm)激发下Er³⁺离子和Dy³⁺离子的相对发射强度及其物理原因.通过真空紫外区激发光谱的测量,确定了Dy³⁺离子的4f⁸5d吸收带以及Er³⁺离子的4f¹⁰5d吸收带的能量位置.实验结果表明,用156.6nm的高能光子激发Er³⁺离子的4f¹⁰5d吸收带,可以产生量子效率高达200%的量子剪裁现象,并给予了合理的解释.     

纳米Ag颗粒表面等离子激元对上转换材料光致发光性能影响的研究

本文采用共烧结工艺将纳米Ag颗粒引入Yb³⁺, Er³⁺共掺的NaYF₄上转换材料中, 利用X射线衍射及扫描电子显微镜技术对制备的NaYF₄材料进行结构特性和表面形貌的表征, 通过吸收谱及荧光光谱测试技术对NaYF₄材料光吸收及光发射特性进行表征. 通过对纳米Ag颗粒引入量的优化, 获得了Yb³⁺, Er³⁺共掺的NaYF₄上转换材料荧光发射峰的增强, 300—800 nm全光谱范围内增益达28%, 在544 nm处获得最大增益55%, 具有显著的荧光增强效果. 同时分析了不同数量纳米Ag颗粒的引入对NaYF₄材料吸收谱及光致发光特性影响, 指出了表面等离子激元的光猝灭及共振吸收增强作用机理.     

Au/Au2S复合纳米球壳微粒的发光特性

观测了金纳米球壳微粒（纳米级Au2S介质外包裹一层纳米级厚的金壳）的荧光光谱，与块状Au2S的荧光峰相比，金纳米球壳的荧光峰蓝移到蓝绿区域，蓝移的主要原因是核－壳纳米复合结构中的表面态和量子尺寸效应。     

退火温度对ZrO2纳米材料中Eu3+离子发光的影响

研究了退火温度对ZrO₂纳米材料中Eu³⁺离子发光性质的影响. 材料的结构、晶粒尺寸和形状以及晶格的排列分别由XRD，TEM表征. 结果表明：用共沉淀法制备的ZrO₂纳米材料具有不随退火温度变化、稳定的四方结构；材料的晶粒尺寸随退火温度的提高而增大；晶格的排列由无序逐渐变为有序；发射光谱表明其主要发射在595 nm和604 nm处；在394 nm的紫外光辐照下得到了不同样品的604 nm荧光发射强度的变化不同. 这种现象与样品中O^2-离子含量和样品表面的表面缺陷有关；另外，电荷迁移带随退火温度的变化而变化.     

薄膜太阳电池用纳米上转换材料制备及其特性研究

以应用于薄膜太阳电池为目的,采用水热法制备了掺杂稀土离子的纳米氟化钇钠上转换荧光材料.研究了稀土离子Yb³⁺/Er³⁺单独和共同掺杂对材料的晶体结构和光学性质的影响.制备的Yb^3＋/Er^3＋共掺材料兼顾了两种稀土离子的光吸收谱,吸收980nm和1530nm附近的红外光,并发出能够被薄膜太阳电池有效吸收利用的红光(653nm)和绿光(520,540nm).优化出较为合适的18％Yb³⁺,2％Er³⁺的掺杂比例,获得了具有较好上转换效果的纳米荧光颗粒材料.     

核心天线CP43、CP47的荧光光谱特性

采用快速扫描成象光谱技术对核心天线CP43和CP47的荧光光谱特性进行研究,获取了它们的积分荧光谱,通过积分荧光谱的组分光谱解析,并结合吸收光谱分析认为CP43和CP47具有这样的Chla的光谱特性,CP43:Chla₆₆₀^662.43、Chla₆₆₉^670.23、Chla₆₈₂^684.02,CP47:Chla₆₆₀^664.91、Chla₆₆₉^671.71、Chla₆₈₀^681.35、(Chla_a^e,a代表吸收峰;e代表发射峰);另外长波长组分694.86nm、702.34nm(CP43)、696.02nm(CP47)可能是由吸收>690nm的Chla分子所产生;CP43与CP47相比还存在有Chla₆₇₅^676.32,但是还没有看到CP43具有675nm吸收谱带的报道.对CP43和CP47的荧光光谱分析,认为CP47中的Chla669nm分子团和Chla680nm分子团间的能量传递比CP43中Chla669nm和Chla682nm分子团的能量传递更为有效;β-Car与Chla分子结合状态在CP47中要比CP43中紧密.     

Comparative adsorption of phenyl selenolate and selenocyanate on Au nanoparticle surfaces

UV-vis absorbance spectra taken at different elapsed time for the surface plasmon band shift indicated that the self-assembly of PhSeCN on gold should be slower than that of phenyl selenolate (PhSeH). A surface-enhanced Raman scattering (SERS) study showed that a trace amount of CN species could remain on Au surfaces when aromatic selenocyanates are reduced to give CN and their selenium atoms bound to the surface. Our concentration dependent SERS spectra suggested that the CN adsorption should be more favorable at higher concentrations of PhSeCN as indicated from more prominent intensites of the CN stretching vibration at 2110-2150 cm⁻¹.     

Near-infrared surface-enhanced Raman spectroscopy of chemisorbed compounds on gold colloids

Near-infrared surface-enhanced Raman scattering (SERS) spectra have been measured for strongly chemisorbed compounds, such as 4-mercaptopyridine and thiophenol, on gold colloids in mixed solvents of ethanol and water using a diode laser as an excitation source. From UV-vis spectroscopy, the aggregated gold colloids show a broad absorbance band through the visible to the near-infrared after adding chemisorbing compounds. The absorption maximum is located in the range 750–850 nm, permitting the use of a near-IR source (826 nm) for the first time in SERS of gold colloid systems. The estimated enhancement is on the order of 10⁵. Transmission electron microscopy of aggregated gold particles revealed a cluster morphology. The aggregated mixed-solvent colloids were more stable than those prepared in water, and were useful in dissolving compounds with poor water solubility.     

纳米ZnO薄膜的光致发光性质

利用溶胶－凝胶法制备了纳米ZnO薄膜,室温下测量了样品的光致发光谱(PL)、吸收谱(ABS)、X射线衍射谱(XRD)．X射线衍射(XRD)的结果表明：纳米ZnO薄膜呈多晶状态,具有六角纤锌矿晶体结构和良好的C轴取向．观察到二个荧光发射带,中心波长分别位于395 nm的紫带、524 nm的绿带和450 nm附近的蓝带．证实了纳米ZnO薄膜绿光可见发射带来自氧空位(VO)形成的浅施主能级和锌空位(VZn)形成的浅受主能级之间的复合;450 nm附近的蓝带来自电子从VO的浅施主能级到价带顶或锌填隙(Zni) 到价带顶或导带底到VZn的浅受主能级的复合．     

Emission characteristics of SPAN-80 activated ZnS nanocolloids

Quantum surface effects (new emission bands, blueshifts, intensity enhancement) were observed in SPAN-80 activated ZnS nanocolloids and explained in terms of time-dependent density functional theory. The experimental evidences were demonstrated for both undoped and Cu, Mn-doped colloidal phases. The photoluminescence spectra of these materials showed a new green band at 520 nm (ZnS:Cu) and a yellow-orange band at 576 nm (ZnS:Mn) besides a blue band at 465 nm. All bands lie in the visible region and are blueshifted, show sharp emissions with narrow widths and have approximately 20-times stronger intensities in comparison with those of the bulk samples. The time-resolved luminescence spectra showed that the life-times of free electrons were 0.12 μs and 1.9 ms in ZnS:Cu and ZnS:Mn correspondingly.     

金纳米粒子的制备及其表面增强拉曼散射效应的研究

采用多巴胺化学还原法制备了分散性良好的纳米金溶胶,并检测了其作为表面增强拉曼散射(Surface Enhanced Raman Scattering,SERS)基底的性质。粒度和透射电子显微镜测试结果表明金溶胶为平均粒径30nm左右的球形颗粒,并且紫外-可见特征吸收峰出现在520nm,为典型的金纳米颗粒特征吸收峰。以罗丹明6G(R6G)为探针分子证明了金溶胶良好的SERS增强效果,用金溶胶对除草剂敌草快(DQ)进行检测,最低检测限可达1×10-7 mol/L。结果表明所制备的金溶胶具有良好的表面增强拉曼散射活性。     

Preparation of Ultrafine Colloidal Gold Particles using a Bioactive Molecule

Synthesis of nanometer-sized particles with new physical properties is an area of tremendous interest. In metal particles, the changes in size modify the electron density in the particles, which shifts the plasmon band. The most significant size effects occur when the particles are ultrafine (size is <10 nm). Thus the synthesis of ultrafine metal particles is enormously important to exploit their unique and selective application. Here we report a novel method for the synthesis of ultrafine gold particles in the size range of 0.5–3 nm using dopamine hydrochloride (dhc), an important neurotransmitter. This is the first time where such an important bioactive molecule like dhc has been used as a reagent for the transformation of Au(III) to Au(0). The synthesis is carried out, for the first time, either in simple aqueous or in a nonionic micellar (for example Triton X-100 (TX-100)) medium. The gold sol has a beautiful yellow–brown color showing _max at 470 nm. The appearance of the absorption peak at substantially shorter wavelength (usually gold sol absorbs at 520 nm) indicates that the particles are very small. The method discussed here is very simple, reproducible and does not involve any reagent, which contains 'P' or 'S' atoms. Also in this case no polymer or dendrimer or thiol-related stabilizer is used. The effects of different parameters (such as the presence or absence of O₂, temperature, TX-100 concentration and dhc concentration) on the formation of ultrafine gold particles are discussed. The effects of 3-mercapto propionic acid and pyridine on the ultrafine gold sol are also studied and compared with those on photochemically prepared gold sol. It is observed that 3-mercapto propionic acid dampens the plasmon absorption at 470 nm of ultrafine gold particles. Pyridine, on the other hand, has no effect on the particles.     

Linear optical absorption and photoluminescence emission properties of gold nanoparticles prepared by laser ablation technique

Gold nanoparticles of average size varying between 1.1 and 3.3?nm are prepared by 1064?nm Nd:YAG laser ablation of solid gold target kept in ethylene glycol medium. The measured UV-Visible absorption spectra showed the presence of sharp absorption peaks in the UV and in the visible regions due to the interband transition and surface plasmon resonance (SPR) oscillations in Au nanoparticles, respectively. The increase in linewidth of the SPR peaks with the reduction in particle sizes is observed due to intrinsic size effects. The prepared samples exhibit photoluminescence (PL) emissions in the UV-Visible region peaked at ??354?nm due to the recombination of electrons with holes from sp conduction band to d-band of Au. The peak PL intensity in the sample prepared with 60 minutes of laser ablation time is enhanced by a factor of ??2.5 compared to that obtained in the sample prepared with a laser-ablation time duration of 15 minutes.     

Optical properties of TiO2 anatase - Carbon nanotubes composites studied by cathodoluminescence spectroscopy

Luminescence spectra obtained by electron bombardment (cathodoluminescence, CL) on TiO₂ (anatase)/carbon nanotubes (CNT) composite, show only one visible band at 498 nm, while the spectra taken from pure anatase samples show two bands at 498 and 545 nm. We demonstrate that the visible luminescence bands are originated by TiO₂ surface defects due to oxygen vacancies, and that this luminescence signal is independent of TiO₂ mineral form (anatase or rutile). Moreover we obtain that the 545 nm band quenching in TiO₂/CNT composites is caused by empty oxygen vacancies (OV) related to oxygen given from oxygen-rich pristine powder of carbon nanotubes. Our conclusions are also supported by X-ray photoelectron spectroscopy (XPS), SEM analysis and energy dispersed X-ray measurements (EDX). Furthermore we can confirm that the NIR TiO₂ luminescence emission is linked only to the presence of Ti rutile form as described in several works in literature.     

Structural and optical properties of Au-implanted ZnO films

The structural and luminescence related optical behaviours of Au ion implanted ZnO films grown by magnetic sputtering and their post implantation annealing behaviours in the temperature range of 100-700 °C have been investigated. Optical absorption and transmittance spectra of the films indicate that band edge of Au-implanted ZnO has shifted to high energy range and optical band gap has increased, because the sharp difference of thermal expansion induces the lattice mismatch between ZnO and SiO₂. PL spectra reveal that UV and visible luminescence bands of ZnO films can be improved after thermal annealing due to recovery of defects and Au ions incorporation. Importantly, green luminescence band of 530 nm has been only observed in the Au-implanted and subsequently annealed ZnO films and it enhances with the increasing annealing temperature, which can be related to Au atoms or clusters in ZnO films. Furthermore, X-ray photoelectron spectroscopy measurements reveal that the Au⁰ is dominant state in Au implanted and annealed ZnO films. Possible mechanisms, such as optical transitions of Au atoms or clusters and deep level luminescence of ZnO, have been proposed for green emission.     

用巯基乙酸作稳定剂制备CdSe纳米晶的光学性质

以巯基乙酸为稳定剂制备了CdSe纳米晶，通过尺寸选择沉淀得到2nm到3nm之间不同尺寸的纳米晶，利用室温光吸收，光致发光（PL）和光致发光激发（PLE）谱来研究了CdSe纳米团簇的光学性质。紫外－可见吸收谱给了具有清晰激光特征的尖锐吸收边，这表明样品的尺寸分布很窄。光致发光研究表明，样品有两个发射带，一个具有较高能量位于吸收边，来自电子－空穴对从最低激发态能级弛豫后的辐射复合，另一个低能发射带归属于基质与纳米晶界面存在的俘获中心。PLE谱中有2个吸收带，分别是S－S和P－P跃迁。最后还给出了不同激发能量下的发光特性。