电沉积表面修饰对染料敏化太阳电池微观性能影响机理研究

为了改善染料敏化太阳电池内电子的传输复合过程, 研究者尝试不同方法制备或改性TiO₂薄膜. 对TiO₂薄膜进行后处理, 在其表面引入一层小颗粒层, 是一种有效的方法并被广泛研究. 通过对TiO₂薄膜不同时间的电沉积表面修饰, 细致研究了表面修饰后染料敏化太阳电池微观性能的变化机制. 采用阳极氧化法在TiCl₃水溶液中对TiO₂薄膜进行电沉积后处理, 将溶液pH值调至2.2, 装置的反应速率由恒电位仪控制. 不同沉积时间电池带边移动以及电子传输复合的动力学过程, 借助强度调制光电流谱(IMPS)/强度调制光电压谱(IMVS)和电化学阻抗谱(EIS)等探测技术表征. 研究表明, 电沉积在TiO₂薄膜表面引入了大量浅能级陷阱态, 以致电势较高时电容随沉积时间延长增加明显. 不同时间的电沉积表面修饰在TiO₂薄膜表面形成了新的小颗粒层并改善了TiO₂颗粒间接触, 在改善电子注入及收集过程的同时, 也有效抑制了内部电子复合. IMPS/IMVS结果表明, 电沉积对动力学过程改善的效果受光强影响明显, 弱光下作用更为突出. 此外, 电池开路电压主要受带边移动及内部复合变化影响, 随沉积时间延长, 表面电荷的增多使TiO₂薄膜带边逐渐正移, 有效改善了光电流却限制了开路电压的提升. 在适合的电沉积时间下, 电沉积表面修饰可以同时改善光电流和光电压.     

Y2O3/TiO2 "核-壳"结构在染料敏化太阳电池中的应用

在纳米TiO₂多孔薄膜表面包覆超薄绝缘体,形成"核-壳"结构的势垒层,是目前染料敏化太阳电池（DSC）光阳极改性的研究热点之一.本文选取氧化钇（Y₂O₃）作为包覆层材料,采用浸渍法对纳米TiO₂多孔薄膜进行修饰,研究Y₂O₃包覆处理对TiO₂薄膜微观结构及能带结构的影响;将浸渍法制备得到的Y₂O₃/TiO₂"核-壳"结构光阳极应用于DSC中,研究了饣覆层对电子传输复合以及DSC光电转换性能的影响.结果表明,Y₂O₃包覆处理后,薄膜的平带电势负移,且电子复合得到有效抑制,电子寿命增大,电池的开路电压明显提高.研究表明,适量引入Y₂O₃可以达改善电池性能的目的.     

共吸附剂修饰TiO2电极及其在染料敏化太阳电池中的应用

在染料敏化太阳电池中, 引入共吸附剂通常有抑制染料聚集和提高电池性能的作用. 通过光谱电化学、线性伏安扫描和电化学阻抗谱(EIS)研究了几种以单羧酸基为吸附基团的共吸附剂对纳米TiO₂薄膜的修饰作用. 结果表明本实验中的共吸附剂均能使TiO₂平带电势负移, 并抑制TiO₂导带电子的复合, 其中胆酸类共吸附剂表现出较好的暗电流抑制性能. 适当浓度共吸附剂的引入能够提高N719染料敏化太阳电池的开路电压、填充因子和光电转换效率.     

表面敏化TiO2基复合薄膜的能带结构与光致电荷转移的研究

采用离子束溅射方法制备出TiO₂/ITO, Zr^4＋掺杂的TiO₂(TiO₂-Zr)/ITO和ZrO₂/TiO₂/ITO复合薄膜. 利用表面敏化方法制备出(1,10-邻菲咯啉)₂(3,4,5-三氟苯基)咪唑并[5,6-f]邻菲咯啉钌混配配合物[Rup₂O](p＝1,10-邻菲咯啉, O＝(3,4,5-三氟苯基)咪唑并[5,6-f]邻菲咯啉)/TiO₂/ITO, Rup₂O/TiO₂-Zr/ITO和Rup₂O/ZrO₂/TiO₂/ITO表面敏化TiO₂基复合薄膜. 表面光电压谱(SPS)表明, 表面敏化TiO₂基复合薄膜在400～600和350 nm产生的SPS响应峰的峰高比与TiO₂基复合薄膜的结构密切相关. 利用电场诱导表面光电压谱(EFISPS)确定了复合薄膜的能带结构, 其结果分析表明, 400～600 nm的SPS响应峰主要源于Rup₂O分子的中心离子Ru 4d能级到配体邻菲咯啉p₁^*和配体咪唑并邻菲咯啉p₂^*跃迁|TiO₂禁带内Zr^4＋掺杂能级的存在减小了光生载流子的复合, 增加导带光生电子的数量|ZrO₂/TiO₂异质结构的存在有利于光生电子向ITO表面的转移, 从而导致400～600 nm和350 nm SPS响应峰的峰高比的增加, 意味着光致电荷转移效率的提高.     

湿空气下制备稳定的CsPbI2Br钙钛矿太阳电池

无机钙钛矿太阳能电池由于具有良好的热稳定性,高吸光系数等优点发展迅速。但无机钙钛矿材料对水分极其敏感,一般在惰性环境下中进行制备,操作复杂。本文通过简单的一步旋涂工艺,在无手套箱空气湿度条件下制备CsPbI₂Br无机钙钛矿薄膜,通过介孔TiO₂厚度的优化,对钙钛矿薄膜的结晶、成膜及稳定性进行了分析,发现在较厚基底介孔层上制备的钙钛矿晶粒大、无孔隙;随着基底厚度的减小,其上所形成的CsPbI₂Br薄膜禁带宽度(E_g)增大;电化学阻抗测试表明在较厚基底介孔层上制备的CsPbI₂Br钙钛矿具有更好的载流子提取与传输能力。对不同厚度介孔层上沉积的钙钛矿薄膜稳定性进行测试,发现CsPbI₂Br钙钛矿的稳定性随着介孔层厚度的增加而提高,在空气中做放置144 h后无明显变化。在空气湿度条件下组装成器件,获得到了8.16%的最佳光电转换效率,并且对器件无任何修饰及封装的情况下,在相对湿地低于35%的空气中放置72 h后保持最初效率的73%。     

n-型多孔Si/TiO2纳米线异质结构的制备及光电化学性能

采用光辅助电化学腐蚀法制备了n-型多孔硅衬底, 再采用水热法在其表面生长TiO₂纳米线制得了三维n-型多孔Si/TiO₂纳米线异质结构. 通过X射线衍射、 扫描电子显微镜和X射线能量散射等表征证实了n-型多孔Si/TiO₂纳米线异质结构的形成. 紫外-可见漫反射光谱测试结果表明, n-型多孔硅与TiO₂纳米线的复合提高了紫外-可见波段的光吸收. 光电性能测试结果表明, 3个样品中n-型多孔Si/TiO₂纳米线异质结作为光电极的光电流最高, 这说明n-型多孔Si/TiO₂纳米线作为光电极具有更高的光电化学分解水性能.     

对电极性能对染料敏化太阳电池动力学过程的影响

借助电化学阻抗谱(EIS)和强度调制光电流谱(IMPS)/强度调制光电压谱(IMVS)技术, 采用不同纳米TiO₂多孔薄膜对电极研究了染料敏化太阳电池(DSC)内部2个主要电荷输运过程的内在联系, 并探讨了载Pt材料对DSC界面动力学过程及电池宏观性能的影响机理. 借助等效电路模型分析了基于不同对电极材料电池的填充因子变化原因. 结果表明, 对电极材料的电极电荷交换过程制约光阳极膜内电子传输, 进而影响电池光伏性能; 同时对电极催化反应速率主要与催化剂活性、 载Pt材料电导率和催化反应面积有关.     

基于MWCNT/TiO2对电极和硫醇盐/二硫化物非碘氧化还原电对的染料敏化太阳能电池性能

采用水热法合成出多壁纳米碳管/二氧化钛(MWCNT/TiO₂)复合物, 并作为染料敏化太阳能电池(DSSC)中对电极材料并组装成电池. 通过场发射扫描电子显微镜(FE-SEM)、傅里叶变换红外(FTIR)光谱、X射线粉末衍射(XRD)、同步热重-差示扫描量热(TGA-DSC)、拉曼(Raman)光谱和光电子能谱(XPS)等方法对其形貌、组成和结构进行表征. 结果表明, 酸化MWCNT表面―COOH与水热生长出的锐钛矿TiO₂表面―OH之间, 通过形成类似于O＝C―O―Ti 或者C―O―Ti 的结构, 能有效地增强复合物薄膜层与导电玻璃基底之间的相互作用. 通过循环伏安(CV)、电化学阻抗谱(EIS)、塔菲尔曲线(Tafel)和电池的伏安特性曲线等方法研究了该类对电极对硫醇盐/二硫化物(T-/T₂)非碘氧化还原电对的光电化学特性. 结果表明: 当MWCNT与TiO₂质量比为3:1时, 基于该复合物对电极与T-/T₂非碘氧化还原电对所组装DSSC的开路电压为0.63 V, 短路电流为15.81 mA·cm^-2, 填充因子为0.65, 光电转换效率达到6.47%.     

双功能型吡啶基离子液体的性质及在染料敏化太阳电池中的应用

采用高压釜无溶剂法合成了一种吡啶碘离子液体1-乙基-4-叔丁基吡啶碘(TBEPI), 并将其应用到染料敏化太阳电池(DSC)中. 利用电化学阻抗谱(EIS)、循环伏安(CV)和傅里叶变换衰减全反射红外光谱(ATR-FTIR)研究了TBEPI作为碘源的电解质的电化学性质、在TiO₂膜上的吸附特性及抑制TiO₂/染料/电解质界面电子复合的动力学过程. 结果表明, TBEPI作为碘源可提供充足的碘离子, 其电解质的电导率、电化学窗口及氧化还原电对的扩散能力都满足电池工作的需要. TBEPI可有效吸附在TiO₂ 表面形成阻挡层, 抑制TiO₂/染料/电解质界面的电子复合过程, 与传统的以1,2-二甲基-3-丙基咪唑碘(DMPII)作为碘源的DSC相比, 光电转换效率(η)由7.1%提高到7.5%.     

氧气氛烧结电极对染料敏化太阳电池微观性能影响机理研究

为了改善染料敏化太阳电池内电子的传输复合过程, 研究者尝试不同方法制备或改性TiO₂薄膜. 不同烧结气氛可以改变TiO₂薄膜的表面特性, 是一种有效的方法并被广泛研究. 采用两步烧结法制备氧气氛烧结TiO₂电极并应用于染料敏化太阳电池:第一步将电极在空气或氧气氛中510℃保温30 min以清除TiO₂薄膜中有机物; 第二步将电极进一步在氮气氛中510℃保温10 min以移除电极表面吸附的多余氧原子. 通过与空气烧结电池宏观性能及微观性能的对比, 细致研究了氧气氛烧结电极表面特性对染料敏化太阳电池传输复合微观动力学过程的影响机制. TiO₂薄膜表面特性及带边移动、电子传输复合过程的表征分别借助XPS能谱仪和强度调制光电流谱(IMPS)/强度调制光电压谱(IMVS)等探测技术完成. 结果表明, 氧气烧结电极Ti³⁺复合中心减少, 使电池内部电子复合得到有效抑制. 同时, 氧气烧结电极染料吸附量增加且导带边正移, 使得光生电子浓度升高, 膜内电子传输过程加快. 最终, 氧气烧结电极有效改善了电池光吸收效率、电子收集效率以及注入效率, 使电池效率由6.90%提升至7.53%.     

Dichroism of absorption and polarization of phosphorescence of molecules of the closed form of nitrobenzospirothiopyran

The spectral-polarization characteristics of absorption and phosphorescence of molecules of the initial form of nitro-substituted indolinospirobenzothiopyran were studied in oriented polyethylene films and in solutions with different polarity. An oscillator model of the electron transitions responsible for the formation of absorption and luminescence spectra was suggested. It was established that the principal differences in the spectral and photophysical properties of the compound studied and its oxygen-containing analog are associated with the fact that the electronegativity of the S atom is lower than that of the O atom. Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 6, pp. 1143–1146, June, 1997.     

Synthesis of phenolic components of Grains of Paradise

Two vanilloids, (5E)-8-(4-hydroxy-3-methoxyphenyl)oct-5-en-4-one (1) and 4-[3-hydroxydecyl]-2-methoxyphenol (2), isolated from the dried seeds of Grains of Paradise (Aframomum melegueta), were synthesized; the latter compound was made as the S-enantiomer and the material derived from the seeds was found to be a 1:1.7 mixture of the R and S isomers. The synthetic route used should allow the preparation of analogs having extended alkyl chains and consequently different lipophilicity, and 3, a homolog of 2, was also prepared.     

Study of hydration of two cements of different strengths

Main hydration products of two cement pastes, i.e. CSH-gel, portlandite (P) (and specific surface S) were studied by static heating, and by SEM, TEM and XRD, as a function of cement strength (C-33 and C-43) hydration time (th) and subsequent hydration in water vapour.Total change in mass on hydration and air drying, M_o, increased with strength of cement paste and with hydration time. Content of water escaping at 110 to 220°C, defined as water bound with low energy, mainly interlayer and hydrate water, was independent on cement strength but its content increased with (th). Content of chemically bound (zeolitic) water in CSH-gel, escaping at 220-400°C, was slightly dependent on strength and increased with (th). It was possibly derived from the dehydroxylation of CSH-gel and AFm phase. Portlandite water, escaping at 400-500°C, was independent on cement strength and was higher on longer hydration. Large P crystals were formed in the weaker cement paste C-33. Smaller crystals were formed in C-43 but they increased with (th). Carbonate formated on contact with air (calcite, vaterite and aragonite), decomposed in cement at 600-700^oC. It was high in pastes C-33(1 month) and C-43(1 month), i.e. 5.7 and 3.3%, respectively; it was less than 1% after 6 hydration months (low sensitivity to carbonation) in agreement with the XRD study showing carbonates in the air dry paste (1month), and its absence on prolonged hydration (6 months) and on acetone treatment. Water vapour treatment of (6 months) pastes or wetting-drying increased this sensitivity.Nanosized P-crystals, detected by TEM, could contribute to the cement strength; carbonate was observed on the rims of gel clusters.This revised version was published online in November 2005 with corrections to the Cover Date.     

Acid hydrolysis of carboxymethylcellulose of low degree of substitution

Cotton cellulose was swollen in a sodium hydroxide solution and carboxymethylated by a two-bath method for different periods of time for each process. The kinetics of acid hydrolysis and the crystallinity of the swollen and carboxymethylated samples were measured. The proportion of broken bonds, rate constants for hydrolysis, and permeability of cellulose to hydrolyzing agents were calculated. The susceptibility of glycosidic linkages to acid hydrolysis was improved by carboxymethylation more than by swelling in alkali. The increased accessibility of carboxymethylcellulose to acid was regarded as a consequence of increased intra-and intercrystalline swelling and of the glycosidic bonds' weakness caused by the electron-attracting carboxymethyl group on the C-6 position.     

非那雄胺合成工艺改进

非那雄胺能抑制5α-还原酶的活性,明显降低二氢睾酮水平,是一种治疗良性前列腺增生的有效药品。该合成工艺以甾烯酮酸为原料,将其与氯化亚砜反应,无须分离即与叔丁胺反应得17β-酰胺化合物,再氧化开环,环合,氢化,脱氢合成了非那雄胺。经元素分析、IR、1HNMR、13CNMR、MS分析表征了其结构。该法无须使用昂贵的2,2-二吡啶二硫化物和剧毒药品苯亚硒酸酐,且以乙酸铵代替氨气,降低了对设备的要求和腐蚀,更适用于工业生产。     

Determination of heats of detonation and influence of components of composite explosives on heats of detonation of high explosives

The heats of detonation of 20 simple high explosives and explosive mixtures were determined by means of an adiabatic detonation calorimeter designed by the authors. The results indicated that the performance of the instrument was reliable and the experimental data were very accurate. For explosive mixtures, there was a linear accumulative relationship between the heats of detonation of the explosive mixture and its components. Accordingly, the heats of detonation of explosive mixtures could be calculated directly from the heats of detonation of simple explosives and the characteristic heats of other components. The experiments showed that the gold or brass shell of the cylindrical charge could be substituted by a thick-walled porcelain shell, which had the advantage of cheapness.

     

Estimation of Kinetic Parameters of Thermal Oxidation of Ilmenite

The aim of the presented work was the investigation of thermal oxidation of ilmenite in static air atmosphere. The investigations were carried out by use of a derivatograph (MOM, Hungary). The changes of crystallographic structure of investigated samples were identified by X-ray diffractometry on Philips PW-1710 diffractometer. In temperature above 500°C appears structure of hematite Fe₂O₃. On the basis of the thermogravimetric measurements, the contracting area and contracting volume models were found as the best fitting experimental data. This revised version was published online in August 2006 with corrections to the Cover Date.     

Mechanism of action of base-catalyzed oxygenation of phenol derivatives

Cyclopropyl derivative of 2,6-di-tert-butylphenol is synthesized as a probe to investigate the mechanism of base-catalyzed autooxidation of phenol derivatives. Our study indicates that one electron reduction of molecular oxygen from phenolate gives phenoxyl radical 3, a key intermediate of autooxidation. The coupling of phenoxyl radical and superoxide radical gives peroxylate anion 4 and produces the final epoxy alcohol adduct 6.     

化学计量中不确定度评定研究进展

测量不确定度是表征合理地赋予被测量之值的分散性的参数。本文针对化学计量不确定度评定基础模型仅适用于线性模型、概率分布为正态分布或缩放位移t分布等局限,介绍了近年来不确定度评定的研究热点:蒙特卡罗方法(Monte Carlo Method,MCM),不确定度评定的来源、评定概念、评估方法及其发展过程,扩大了测量不确定度评定与表示的适用范围。