自组装高导电石墨烯薄膜的光谱特性表征

本文提出了一种石墨烯薄膜的自组装制备技术,获得了高导电、高透明的均匀石墨烯薄膜,并对其进行了参数测试和光谱特性研究。研究表明此方法制备的石墨烯薄膜具有杂质含量少、高导电、高透明、膜厚均匀可控等优点,其平均透过率达到80%,方阻最低可达到0.2Ω/sq,在透明电极和有机光电子学领域有重要应用前景。     

高温还原氧化石墨烯膜及其导热性能

采用氧化还原法制备了结构致密且具有较高柔韧性的石墨烯薄膜,探究了薄膜经过较高退火温度还原后结构变化,并通过T型稳态法测量了其热导率,研究了还原温度对薄膜热导率和力学性能的影响。结果表明,高温还原有助于氧化石墨烯中含氧官能团的去除和sp2杂化碳晶格的恢复,并且温度越高还原效果越好。当还原温度高达2800℃时,在200~350 K温度范围内石墨烯膜的热导率在336.9~436 W·m^-1·K^-1之间,伴随着温度的升高,热导率有先增大后减小的趋势。     

金纳米通道制备及催化性能研究

以聚碳酸酯超滤膜(PC膜)为模板,采用层-层自组装技术将聚乙烯亚胺(PEI)阳离子聚合物和柠檬酸根稳定的金纳米粒子(AuNPs)交替吸附在PC膜孔内制备了金纳米通道,并采用SEM对其进行了表征。以紫外-可见吸收光谱作为分析手段研究了金纳米通道对对硝基苯酚(4-NP)还原反应的催化性能。结果表明,金纳米通道具有良好的催化活性,催化效率随组装层数的增多出现先增大后降低的现象,PEI/AuNPs为三层时,金纳米通道具有较高的催化性能,且催化效率随4-NP+NaBH4混合溶液体系在金纳米通道内的流速增大而减小。     

十八胺LB膜吸附组装金纳米颗粒研究

制备了十八胺单层、多层LB膜及粒径为几个纳米的金纳米粒子。pH值小于10.3时十八胺带正电荷,将其置于金纳米溶胶(pH值10.3)中,带负电荷的金纳米粒子与带正电荷的十八胺之间通过静电作用,金纳米颗粒被成功地吸附组装到十八胺LB膜中,形成纳米薄膜。紫外-可见光谱、红外光谱及扫描电镜显示:金纳米颗粒通过这种方法能够很好的组装在十八胺LB膜上,且其组装层整齐有序,同时也受十八胺LB膜层数及组装时间的影响。     

氧化石墨烯与水溶性酞菁铜的表面增强拉曼散射光谱特性研究

采用氧化石墨烯(GO)作为表面增强拉曼散射的基底,水溶性酞菁铜(TSCuPc)作为探针分子,实验探究了氧化石墨烯薄膜的层数和TSCuPc薄膜的厚度对拉曼散射增强的影响。首先配制了不同浓度的GO溶液,利用旋涂法在玻璃基底上制备了不同层数的GO膜,然后通过调节TSCuPc薄膜的旋涂转速,制备了GO和TSCuPc的复合薄膜。实验结果表明,当增加GO薄膜层数时,由GO和TSCuPc产生的π-π共轭所感应的分子极化率和由GO含氧官能团感应的局域电场均增大,因此TSCuPc分子的拉曼强度增大,且随着层数的增加,增强呈现饱和趋势;而随着TSCuPc薄膜厚度的增加,由于其自身分子间也存在π-π共轭,TSCuPc分子的拉曼光谱强度呈近似线性增加,且由TSCuPc薄膜厚度引起的首层效应并不是很明显。选用的可以溶液法成膜的TSCuPc分子,通常被用作有机光电子器件的空穴注入材料,研究GO与TSCuPc的表面增强拉曼光谱特性,为优化器件参数以提高有机光电子器件的电荷转移效率等性能具有重要的意义。     

通过光致还原调制氧化石墨烯寿命并用于微纳图形制备

氧化石墨烯因其宽带可调谐的荧光发射特性已被广泛应用于荧光成像、金属离子高灵敏检测和光电器件的制备.相比于荧光强度,氧化石墨烯荧光寿命不受材料厚度和激发功率的影响,具有更为稳定和均一的特性.本文研究了在激光还原过程中氧化石墨烯荧光寿命逐渐减小的变化行为,发现了长寿命sp~3杂化结构向短寿命sp~2杂化结构的转变.通过精确控制还原时间,结合激光直写技术,在单层氧化石墨烯薄膜上实现了二维码、条形码、图形和数字等微纳图形的制备,还在多层氧化石墨烯薄膜结构上获得了多寿命多层微纳图形.这种微纳图形的制备具有灵活无掩膜、高对比和多模式的特点,可用于高密度光学存储、信息显示和光电器件制备等诸多领域.     

电化学制备钛网负载聚吡咯/石墨烯复合膜及其在超级电容器中的应用

通过电化学的方法在钛网上制备了聚吡咯与石墨烯的复合物薄膜,其过程是先在钛网上通过自组装干燥膜法附着上石墨烯氧化物膜,而后采用电化学还原的方法原位还原制备得到石墨烯膜,随后加入吡咯单体,再通过电化学聚合的方法在石墨烯的表面生长聚吡咯,得到的聚吡咯开始以颗粒的形式存在,而后随着聚合的进行得到了链状的聚吡咯.得到的复合膜有高的比表面积和导电性,可以作为电极活性材料用于超级电容器中提供赝电容,结果表明,复合膜作为电极材料的超级电容器拥有高的性能,比电容达400 F/g,并且电极的充放电稳定性高,5000次复合膜充放电循环后比电容还能保留82%,说明该材料适合于超级电容器.     

基于溶液加工氧化石墨烯的高性能有机太阳能电池

采用溶液旋涂法在铟锡氧化物(ITO)电极上制备氧化石墨烯(GO)薄膜作为有机太阳能电池(OPVs)的空穴传输层,通过调控旋涂转速优化了氧化石墨烯薄膜的厚度并研究了膜厚对于器件性能的影响规律。在此基础上,通过紫外臭氧(UVO)处理和热处理等方法进一步提升电池器件的性能。结果表明:在紫外臭氧处理和热处理温度为250℃时,所得电池器件的效率最优,达到3.16%,接近于使用经典聚(3,4-乙撑二氧噻吩):聚苯乙烯磺酸(PEDOT:PSS)材料的电池器件水平。这一结果表明具有低成本、可溶液加工以及优异的光透过性等特点的氧化石墨烯会成为一种未来非常有前景的有机太阳能电池的空穴传输层材料。     

人血清白蛋白微/纳米管的制备及影响因素

以聚碳酸酯(polycarbonate,PC)为模板,聚乙烯亚胺(polyethyleneimine,PEI)为连接剂,采用静电层层自组装技术制备了人血清白蛋白(human serum albumin,HSA)微米管和纳米管,讨论了溶液pH、离子强度、组装层数、沉淀清洗次数和模板孔径对组装效果的影响。利用扫描电子显微镜(SEM)、透射电子显微镜(TEM)、傅里叶变换红外光谱仪(FTIR)和X射线能谱仪(EDS)对蛋白质微/纳米管的结构和组成进行了表征。结果表明,溶液pH和离子强度是影响组装效果的关键因素,在HSA和PEI溶液pH分别为7.4和10.3,且PEI溶液不含NaCl的条件下组装得到的微/纳米管具有良好的中空开口管状结构;微/纳米管的外径由模板孔径决定;调节组装层数可控制管壁厚度,且组装层数越多,管壁越厚,由此可实现对微/纳米管内径大小的调控;为保证管状结构的完整性,避免较薄的管壁在模板溶解和真空干燥过程中造成破坏,PEI/HSA双分子层数应不少于3;采用极性胺基溶剂N,N-二甲基甲酰胺(N,N-Dimethylformamide, DMF)可较好地溶解PC模板从而释放管状物。     

还原温度对氧化石墨烯结构及室温下H_2敏感性能的影响

以氧化石墨凝胶制备的氧化石墨烯(GO)溶胶为前驱体,在100—350℃温度下还原获得不同还原程度的还原氧化石墨烯(rGO)样品,并采用旋涂工艺制备还原氧化石墨烯气敏薄膜元件.采用X射线衍射、拉曼光谱、傅里叶变换红外光谱和气敏测试等手段研究还原温度对样品结构、官能团和气敏性能的影响.结果表明:经热还原处理的氧化石墨烯结构向较为有序的类石墨结构转变,还原温度为200℃时,样品处于GO向rGO转变的过渡阶段,还原温度达到250℃时,则表现出还原氧化石墨烯特性;无序程度随还原温度的升高先由0.85增大至1.59,随后减小至1.41,总体呈现增加趋势;氧化石墨烯表面含氧官能团随还原温度的升高逐渐热解失去,不同含氧官能团的失去温度范围不同;热还原氧化石墨烯具有优异的室温H_2敏感性能,随着还原温度的升高,元件灵敏度逐渐减小,响应-恢复时间逐渐增大,最佳灵敏度为88.56%,响应时间为30 s.     

History of spectroscopy and modern micromachined disposable Si ATR-IR spectroscopy

In this article, the historical development of spectroscopy is examined and the spectroscopy devices used today are described. Then, we focus on infrared (IR) spectroscopy, which cannot give valuable signal in aqueous solution. Attenuated total reflection (ATR)-IR technique solves the problem. In addition, we specifically mention newly developed disposable ATR-IR crystals and micromachined silicon (Si) ATR-IR. Disposable crystal systems and microfluidics systems can be integrated with existing miniature ATR analyzers. If the integration is successful, the technique might be used in biomedical measuring instruments, reactions' analyses, and ultra-high-pressure analyses.     

Synthesis,Structural and Optical Studies of Barium Strontium Titanate Borosilicate Glasses Doped with Ferric Oxide

Various barium strontium titanate borosilicate glasses were prepared by a rapid melt-quench technique. Spectroscopic studies have been carried out on investigated glasses for their structural information. Infrared and Raman spectroscopic studies showed that these glasses are formed by glass-forming network of borate and silicate as well as network modifiers in the form of cations of alkaline earth atoms. The borate and silicate networks are modified by barium, strontium, titanium, and iron cations in glass matrix. The network of triborate unit is modified in tetraborate unit by adding ferric oxide in a glassy matrix. The optical studies are performed by ultraviolet-visible spectroscopy and it confirms that the band gap decreases with increase in the concentration of ferric oxide.     

一种实现光声光谱的导数光谱的新方法

提出了一种实现光声光谱的导数光谱的新方法,为了获得光声光谱的导数光谱,利用一台单色仪和一个分光棱镜研制成一个波长-光强分束器,并用这个波长-光强分束器同时获得两束光强相等而波长有微小差别的两束光,这两束光经过一个互补调制器调制后在光声探测器内叠加,可以实现光声信号的差分,扫描单色仪的波长,就可以获得光声吸收光谱的导数光谱。实验证明这种方法可以准确实现光声光谱的一阶导数光谱,而且导数光声光谱比光声吸收光谱具有更高的光谱分辨率。     

激光长程吸收光谱法测量高分辨率大气吸收光谱

用脉冲可调谐光参量振荡器作光源 ,使用光程长达 1km的 8m长吸收池 ,采用分时复用的单探测器探测方法 ,组成测量系统 ,测量了一系列高分辨率的模拟和实际大气的吸收光谱。系统的灵敏度为 0 .5× 10 - 6cm- 1 ,分辨率为 0 .0 2cm- 1 。 1.315 μm附近实际大气的吸收光谱与HITRAN96模拟结果比较 ,强线符合得很好。水汽光谱的大多数强线的分子线强度相对误差在 10 %以下。     

Determination of Total Petroleum Hydrocarbon (TPH) and Polycyclic Aromatic Hydrocarbon (PAH) in Soils: A Review of Spectroscopic and Nonspectroscopic Techniques

Abstract: In the analysis of petroleum hydrocarbon–contaminated soils for total petroleum hydrocarbons (TPHs) and polycyclic aromatic hydrocarbons (PAHs), the roles of spectroscopic and nonspectroscopic techniques are inseparable. Therefore, spectroscopic techniques cannot be discussed in isolation. In this report, spectroscopic techniques including Raman, fluorescence, infrared, and visible and near-infrared (Vis-NIR) spectroscopies, as well as mass spectroscopy (coupled to a gas chromatograph) and nonspectroscopic techniques such as gravimetry, immunoassay, and gas chromatography with flame ionization detection are reviewed. To bridge the perceived gap in coverage of the quantitative applications of Vis-NIR spectroscopy in the rapid determination of TPHs and PAHs in soils, a detailed review of studies from the period 1999–2012 are presented. This report also highlights the strengths and limitations of these techniques and evaluates their performance from the perspective of their attributes of general applicability, namely economic portability, operational time, accuracy, and occupational health and safety considerations. Overall, the fluorescence spectroscopic technique had the best performance (85% total score) in comparison to the others, and the gravimetric technique performed the least (60% total score). Method-specific solutions geared toward performance improvement are also suggested.     

磁旋转腔增强光谱技术

为了提高吸收光谱的探测灵敏度,在弱吸收或短光程吸收的情况下实现高灵敏探测,将腔增强光谱技术与磁旋转光谱技术有效地结合起来,发展了高灵敏的磁旋转腔增强吸收光谱技术,并通过测量O2 的三重禁戒跃迁谱线验证了该技术的探测灵敏度。实验采用环型增强腔,以避免光束的返回对激光器的干扰。给出了腔的耦合匹配条件,以及镜面反射率、腔损耗对增强因子的影响;同时也给出了在实验中对光谱信号的处理方法。测量结果表明,在谐振腔精细度为F=48,腔内总损耗为13%,以及腔镜的耦合效率为 95%的情况下,对 O2 分子最小相对吸收度约为4.5×10-8(1 s积分时间)。     

Millimeter wave measurement and assignment of the rotational spectrum of aniline

Previous work involving the rotational spectrum of aniline was limited to the lower frequencies of 8-40 GHz with very few lines being assigned. This work extends the earlier studies. Here we present a much more extensive measurement and assignment of the rotational spectrum of aniline in the frequency range of 75-110 GHz. The observed frequencies have been assigned to the ground (0⁺), first (0⁻), and second excited (1⁺) states in the inversion vibration. With the newly assigned lines, significantly improved rotational constants and all five centrifugal distortion constants have been obtained.     

Rotational spectroscopy of the first excited state of the acetylenic C-H stretch of 3-fluoropropyne performed by infrared-Fourier transform microwave-microwave triple-resonance spectroscopy

The rotational spectra of 3-fluoropropyne in the ground and first excited acetylenic C-H stretch vibrational state have been measured. The pure rotational spectrum of the normal species and the ¹³C isotopomers were measured using FTMW-cwMW double-resonance spectroscopy based on the Autler-Townes (AC Stark) effect. The lineshape properties of this measurement make it possible to determine the transition strength, ΔJ-selection rules, and the relative energy ordering of the quantum states. The frequency accuracy of this technique is tested against a previous pure rotational study of 3-fluoropropyne. The rotational spectrum of vibrationally excited state was obtained through IR-FTMW-cwMW methods. In this technique a single-longitudinal-mode pulsed infrared laser source vibrationally excites the acetylenic C-H stretch with J-selectivity. The rotational spectrum of the excited state is then obtained by FTMW and FTMW-cwMW double-resonance methods. The excited-state measurements have a signal-to-noise ratio comparable to the pure rotational spectrum. The residuals in the excited-state fit are larger than those obtained in the ground-state fit. This greater deviation from a standard asymmetric top spectrum is most likely due to weak perturbations to the acetylenic C-H spectrum.     

Sub-Doppler and Doppler spectroscopy of DCN isotopomers in the terahertz region: ground and first excited bending states (v1v2v3)=(0 1 0)

The rotational spectra of the deuterium cyanide isotopic species DCN, D¹³CN, DC¹⁵N, and D¹³C¹⁵N were recorded in the vibrational ground and first excited bending state (v₂=1) up to 2 THz. The R-branch transitions from J=3←2 to J=13←12 were measured with sub-Doppler resolution. These very high resolution (∼70 kHz) and precise (±3-10 kHz) saturation dip measurements allowed for resolving the underlying hyperfine structure due to the ¹⁴N nucleus in DCN and D¹³CN for transitions as high as J=10←9. Additional high JR-branch (J=25←24 to J=28←27) transitions around 2 THz and direct l-type (ΔJ=0, J=19 to J=25) transitions from 66 to 118 GHz were recorded in Doppler-limited resolution. For the ground state of D¹³C¹⁵N, the J=1←0 transition was measured for the first time. The transition frequency accuracies for the other deuterated species were significantly improved. These new experimental data, together with the available infrared rovibrational data and previously measured direct l-type transitions, were subjected to a global least squares analysis for each isotopomer. This yielded precise sets of molecular constants for the ground and first excited vibrational states, including the nuclear quadrupole and magnetic spin-rotation coupling constants of the ¹⁴N nucleus for DCN and D¹³CN. The hyperfine structure due to the D, ¹³C, and ¹⁵N nuclei have not been resolved, but led to a broadening of the observed saturation dips.     

Millimeter and submillimeter wave rotational spectrum of pyridine in the ground and excited vibrational states

The pure rotational spectra of the ground and five excited vibrational states of pyridine were measured, assigned and fit in the 75-110 and 260-370 GHz frequency bands. An improved set of spectroscopic constants was obtained for the ground state, and all the rotational and quartic centrifugal distortion constants were obtained for the excited vibrational states.