阴阳离子菁染料超快荧光动力学特性研究

采用飞秒荧光上转换技术，研究了阴阳离子菁染料及对应的阴离子和阳离子菁染料吸附在立方型和T型溴碘化银表面上形成J-聚集体的荧光衰减时间分辨特性，分析了几种菁染料增感体系的超快电子转移动力学过程及其对增感效率的影响．通过比较几种菁染料增感体系的荧光衰减特性，两种阴阳离子染料要明显快于阴离子染料、阳离子染料及二者的加合，说明阴阳离子染料聚集体到溴碘化银的电子注入速率较快，增感效果更好．对两种阴阳离子染料聚集体荧光衰减特性的比较，可以看出染料在T型颗粒溴碘化银上形成聚集体的荧光寿命更短，因而对T型颗粒的增感效果更好．染料Dye2的荧光衰减要快于染料Dyel，说明染料Dye2到溴碘化银的电子注入速率更快，增感效率更高．     

吸附在溴化银颗粒表面上的增感染料的ESR波谱研究

本文用电子顺磁共振技术研究了光照条件下三十八种增感染料与溴化银之间发生的电子转移过程。增感染料和溴化银无论在黑暗处还是在光照下,均不产生ESR信号。当增感染料吸附在溴化银颗粒表面上时,如不加光照,仍看不到ESR信号。只有在光照条件下,才有可能观察到ESR信号,这主要取决于增感染料分子的最高占有能级与溴化银价带的相对位置。若染料分子的最高占有能级比溴化银价带顶部高0.7 eV,就可以观察到ESR信号,反之则观察不到。顺磁性中心是由染料正空穴Dye形成的。根据ESR信号的强度可以判断增感染料是否有较强的减感作用。     

温度条件对光谱增感AgCl晶体光电子特性的影响

利用微波吸收相敏技术检测了光谱增感AgCl立方体乳剂的光电子时间分辨谱,增感样品由于染料吸附引起填隙银离子浓度增加,其光电子衰减比未增感的要快。通过分析增感温度条件与光电子特性的关系,发现温度条件影响了染料吸附程度,进而影响了光电子的衰减特性。温度为45℃时,晶体受染料吸附的影响最大,光电子衰减最快。低于或高于此温度时染料吸附不充分或存在生成大聚集体的趋势,引起晶体填隙银离子浓度的变化较小,光电子衰减较慢。     

染料聚集态中空穴传递的顺磁共振研究

本文应用了顺磁共振波谱技术,研究了染料J-聚集体对染料正空穴俘获电子的影响。 实验所用乳剂是未经化学增感的溴化银(AgBr),染料用量2.5×10~(-4)摩尔染料/摩尔银。涂片厚度为3微米左右。     

纳米硫化铅增感的溴化银微晶中光电子衰减特性研究

采用纳米硫化铅作为增感剂对边长为0.8μm的溴化银立方体颗粒进行了化学增感．利用微弱信号的微波吸收相敏检测技术，在超短脉冲激光作用下，获得了立方体溴化银乳剂中自由光电子和浅束缚光电子随增感时间变化的衰减曲线。通过测量溴化银光作用过程的时间分辨谱，讨论了卤化银晶体中电子陷阱对光电子运动行为的影响，分析了电子陷阱效应同增感时间之间的关系以及两个一级衰减区间寿命值同增感时间的关系．通过未增感样品与增感样品的衰减曲线对比，得到了在此实验奈件下的最佳增感时间为60min．     

草酸盐掺杂八面体溴化银颗粒乳剂的增感效应研究

使用反馈式微机控制双注乳化仪,在晶体生长过程中一定时间内,加入一定量的草酸盐,制得了草酸根离子处于晶体颗粒次表面的八面体溴化银微晶乳剂。考察其实验过程和测试其感光性能,结果表明:(1)草酸根掺杂于次表面的八面体溴化银乳剂与未掺杂乳剂相比较,无论是原始乳剂,还是经过化学增感,或用染料进行光谱增感后的乳剂,感光度均有明显提高(Sd/S0≥1.8),且其灰雾水平都不高,即具有明显的增感效应;(2)草酸根掺杂的乳剂可以与常规的硫加金化学增感,以及染料光谱增感一同进行协同增感,把乳剂的感光度提高到更高的水平。(3)草酸根掺杂的八面体溴化银乳剂的感光度增益,明显高于草酸根掺杂立方体溴化银乳剂。     

不同取代基的噻碳菁和吲哚碳菁染料对其在溴化银微晶上吸附能力及形成J-聚集体尺寸分布的影响

本文研究了５－位不同取代基的噻碳菁和吲哚碳菁染料对其在立方型颗粒和Ｔ－颗粒溴化银微晶上吸附能力的影响，并采用ＡＣＦＥＭ（ＡｎａｌｙｔｉｃａｌＣｏｌｏｒＦｌｕｏｒｅｓｃｅｎｃｅＥｌｅｃｔｒｏｎＭｉｃｒｏｓｃｏｐｙ）研究了上述结构染料对其吸附在溴化银微晶所形成的Ｊ－聚集体尺寸分布的影响．实验结果表明，对吲哚碳菁染料来说，立方体溴化银微晶表面的吸附能力较Ｔ－颗粒溴化银微晶表面的吸附能力强；但对噻碳菁染料来说则相反，它们在Ｔ－颗粒溴化银微晶表面的吸附能力较立方体溴化银微晶表面的吸附能力强．另外，对５－位不同取代基的噻碳菁染料而言，无论是在立方型颗粒或Ｔ－颗粒溴化银微晶上的吸附能力来说，含取代基（无论４－取代基是吸电子型还是推电子型）的噻碳菁染料较未取代的噻碳菁染料强；而５－位取代基是吸电子型的噻碳菁染料更有利于其吸附在Ｔ－颗粒溴化银微晶表面．此外，本文还进一步证明了溴化银微晶表面上染料Ｊ－聚集体的生长过程是符合奥斯瓦尔特成熟过程的．吲哚碳菁染料在Ｔ－颗粒溴化银微晶上形成的Ｊ－聚集体的平均尺寸明显大于在立方体溴化银微晶上形成的Ｊ－聚集体的平均尺寸．吸附在立方体溴化银微晶上的５－不同取代基的噻碳菁染料对其形成Ｊ－聚集体     

钙离子对卤化银乳剂化学增感和光谱增感的影响

本文通过控制乳剂中一系列不同的钙离子浓度(4.0～80×10~(-3)mol Ca~(2+)/mol AgX),研究了化学增感时间对钙离子浓度的依赖性,测定了相应的感光特性,结果表明,乳剂中的钙离子在不影响最佳感光度的前提下,可有效地抑制灰雾并延缓化学增感过程,延长化学成熟时间。 经感红染料光谱增感后,测定了染料的相对增感倍率,本征及感红光谱感光度,研究了它们对轧剂中钙离子浓度的依赖关系。以卤化银乳剂对染料的吸附,对光的吸收以及Dember效应的实验结果为佐证,说明钙离子在光谱增感的电子转移过程中,起着电子陷阱的作用,从而抑制感红感光度的增感;与此同时,钙离子又抑制染料对本征感光度的减感,这可能是由于钙离子的存在阻碍了染料正空穴对卤化银本征潜影的氧化,从而保护了部分潜影免受染料正空穴的袭击。     

草酸根掺杂立方体溴化银乳剂颗粒的增感效应研究

使用反馈式微机控制双注乳化仪，在晶体生长过程中一定时间内，加入一定量的草酸盐，制得了草酸根离子处于晶体颗粒次表面的立方体溴化银微晶乳剂．对其实验过程的考察和感光性能的测试结果表明，（1）草酸根掺杂于次表面的溴化银乳剂与未掺杂乳剂相比较，无论是原始乳剂，还是经过化学增感，或用染料进行光谱增感后的乳剂，感光度都有明显提高（Sd／S0≥1．5），有明显的增感效应；（2）无论是原始乳剂，还是经过化学增感，或光谱增感后的乳剂，草酸根掺杂立方体溴化银乳剂颗粒的灰雾水平都不高；（3）草酸根掺杂立方体溴化银颗粒与甲酸根掺杂的溴化银乳剂相比，产生的增感效应相差不大；（4）与甲酸根掺杂立方体溴化银颗粒相比，草酸根掺杂立方体溴化银颗粒的制备方法明显较前者要简单得多，颗粒形状也优于前者．     

超增感剂的几何位置对超增感过程的影响

本文通过溴化银单晶上的超增感体系的Dember效应测试以及相应实用乳剂体系的研究,观察到超增感作用与体系的Dember效应之间存在平行关系,并以此探讨了超增感荆发挥最佳作用时在溴化银面上增感染料与超增感剂的相对排列位置,实验结果表明,在所研究的超增感体系中超增感剂与溴化银直接接触时超增感作用最为有效。     

卤化银乳剂颗粒上不对称菁染料J－聚体荧光的研究

卤化银乳剂颗粒上不对称菁染料Ｊ－聚体荧光的研究齐晓燕，陈次平，周本茂，阎文鹏（中国科学院感光化学研究所，北京１００１０１）关键词光谱增感，染料Ｊ－聚体，荧光，荧光寿命，电子转移光谱增感机理的研究是感光科学中的一个重要课题Ｇｉｌｍａｎ［１］和Ｋｕｈｎ等...     

某些硫碳菁染料在溴碘化银乳剂中聚集态的研究

本文应用三种不同晶形的溴碘化银乳剂(立方体、八面体和T-颗粒)和八种硫碳菁染料(大部分为内铵盐结构染料)进行了染料的聚集态的研究。试验结果表明,染料的J-聚集态的形成主要取决于染料的结构,其次依赖于卤化银的晶形。三种不同结构的表面活性剂对染料聚集态的形成均有影响,其中两性的表面活性剂最强,阴离子的表面活性剂次之,中性的表面活性剂最弱。二种中位甲基取代的硫碳菁染料的聚集态受表面活性剂影响最为明显,形成较强的J-态,而对其它六种染料的聚集态影响较小,J-聚集态稍有增强。     

Electrochemical investigations on spectral sensitisation of silver halide crystals

Photocurrents and photovoltages were studied with single crystal plates of AgCl and AgBr as electrodes of an electrochemical cell. The photoresponse in the presence of sensitising dyes in the electrolyte corresponds to the absorption spectrum of the dye in that wave length range where the crystals do not absorb the light to any considerable amount. The technique described can be used for testing the suitability of dyes as sensitisers. The mechanism is discussed as electron injection from the excited dye molecules into the conduction band of the silver halides.     

水溶性菁染料与类脂物混合单分子膜中J-聚集体形成的研究

报道了具有相同发色团,并有不同电荷的二种菁染料单分子膜中J-聚集体的形成。测定了单分子膜的π/A,△V/A曲线,反射光谱及吸收光谱。从实验结果得出:带正电荷的染料与花生酸混合形成单分子膜后,膜中染料的二聚体与J-聚集体随着表面压力改变存在着一个平衡。而带负电荷的染料与二十烷基胺成膜后,即使在很低的表面压下也有J-聚集体形成。同时染料分子在水面上的取向是各向异性。     

Mass transfer model for the adsorption of basic dyes on woodmeal in agitated batch adsorbersStoffübergangsmodell für die Adsorption basischer Farbstoffe an Holzmehl in durchmischten,absatzweise betriebenen Adsorbern

The adsorption of three basic dyes, Basic Blue 3, Basic Blue 69 and Basic Orange 2, onto woodmeal has been studied in batch adsorbers. The effects of initial dye concentration and mass of woodmeal have been studied.A two-resistance mathematical model has been developed based on external mass transfer, pore diffusion and the assumption of an irreversible isotherm for operating conditions lying on the monolayer of observed Langmuir isotherms. The model, which has an analytical solution, predicts theoretical concentration decay curves which show good agreement with observed experimental decay curves.     

Pore size dependence of self-assembled type photonic crystal on dye-sensitized solar cells efficiency utilising Chlorine e6

There are few reports on photoelectric conversion efficiency using naturally-occurring dyes for dye-sensitized solar cells (DSSC). This is because the matching with an excited electronic level of naturally-occurring dye to the conduction band of semiconductor is problematic; the excited electrons are easily relaxed to the steady state with fluorescence or heat emission. We examined the fluorescence inhibition effect of a self-assembled photonic crystal using Chlorine e6 dye. Chlorine e6 is derived from chlorophyll and has a long excited electron lifetime. We prepared TiO₂ inverse opals with various particle sizes by liquid phase deposition and described their effect on DSSCs with regard to structural, optical and electrochemical properties. In addition, we explored the implications of fluorescence lifetime measurements relative to the photonic band diagram and the amount of adsorbed dye. Although the main factor affecting the external photoelectric conversion efficiency was the diffusion resistance of the electrolyte and the contact resistance between TiO₂ interfaces, the possibility that the dye fluorescence lifetime, i.e. the photonic band structure, can affect the internal quantum efficiency per one dye molecule was also investigated.     

The Behaviour of Dyes in Continuous Vacuum Transfer

A laboratory apparatus has been constructed to study the behaviour of disperse dyes in vacuum transfer printing. Equations have been derived whereby the results of dye transfer experiments can be expressed in the form of curves relating the degree of vacuum to transfer efficiency and time of transfer. Problems associated with the choice of suitable dyes for the transfer printing of different fabrics are discussed. The Stork TC 451 vacuum calender is described and illustrated diagrammatically.     

Effect of side chain substituents on the electron injection abilities of unsymmetrical perylene diimide dyes

Three near-infrared (NIR) absorbing unsymmetrical perylene diimide D-A-D type dyes containing 6-undecanoxy as donor group were utilized in dye-sensitized nanocrystalline TiO₂ solar cells. Structure of the acceptor side of the molecules were improved by adding 4-[2-methyl-5-(cyanoacrylic acid)-3-thienyl]-phenyl (V), 3-carboxy-2-pyridil (VI) and 3-carboxy-2-pyrazyl (VII) moieties attached to one of the N-side of the dye. The relationship between the molecular structure of the acceptor sites of the dyes and the photovoltaic performances were discussed. Electrochemical measurements indicated that band gaps of the dyes were energetically favorable for electron injection from the excited state of the dyes to the conduction band of TiO₂ nanoparticles. However, three dyes gave lower conversion efficiency on DSSC applications. Strong electron-withdrawing nature of perylene core might not permit to transfer the photo-generated electrons to the carboxyl groups anchoring to TiO₂ surface, and then solar-to-electricity conversion efficiencies of the dyes were reduced.