共查询到19条相似文献,搜索用时 171 毫秒
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本文测定了八个照相染料在不同pH条件下的还原电位。发现其中一些增感染料的还原电位与其溶液的pH值无关,而一些减感染料依赖于pH值的变化。本文用染料质子化机理分析了这些结果。 相似文献
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本文以电沉积在银电极上的卤化银作为模型,使用计时电位法和电子显微镜研究了染料在溴化银上的吸附。证实了卤化银在吸附菁染料以后,形成了一种电惰性的络合物,这种络合物的多寡与增感能力有一定关系。文中还定量地用条件解离常数K′来表征这种络合物在电场中的稳定性,并计算了几种菁染料的K′值。 相似文献
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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(Analytical Color Fluore scence Electron Microscopy)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-聚集体尺寸分布的影响的研究结果表明,含取代基(-CH3,-Ph,-Cl)的噻碳菁染料形成的J-聚集体的尺寸分布几乎相同,但与未取代的噻碳菁染料形成的J-聚集体的尺寸分布明显不同;5-位含取代基的噻碳菁染料形成的J-聚集体平均尺寸大于未取代的噻碳菁染料的。 相似文献
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本文用计时电位法及电位滴定研究了十六种不同染料与溴化银之间的相互作用,进一步证明了具有离域π-电子的菁染料才能与卤化银形成络合物的论点。从得到的平衡常数K表明,固体表面上的卤化银-染料与溶液中银离子-染料具有相同键性质,都是银离子与染料离域π-电子作用的结果。 相似文献
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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。 相似文献
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用电化学循环伏安法研究真丝绸上染料的光褪色,发现真丝绸中的某些氨基酸和染料、氧分子3者间可以形成电荷转移复合物。这些三元电荷转移复合物的还原电位比染料本身的还原电位明显正移。用的光照射,证明是真丝绸中的氨基酸加速了阳离子染料的光褪色。 相似文献
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本文用可见吸收光谱、核磁共振谱、红外光谱等分析方法,研究了Nd、Eu与阳离子染料、酸性染料、活性染料及直接染料之间的相互作用。结果表明稀土与大多数染料之间没有形成稳定的配合物,在中性或酸性条件下与含磺酸基的染料之间只形成磺酸盐,与含羧酸基的染料之间形成羧酸盐。只有与酸性媒介染料之间形成稳定的配合物,其结构与铬及其配合物相似。 相似文献
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增感染料在卤化银微晶上吸附并形成J-聚集体是染料光谱增感和超增感的关键步骤.本文利用紫外-可见吸收光谱研究了增感染料和阻光染料在氯化银微晶上的吸附,并考察了阻光染料对增感染料J-聚集体的形成及乳剂感光性能的影响.结果表明:不同阻光染料在氯化银微晶表面的吸附程度不同,对增感染料J-聚集体形成的影响也有差异.其中,吸附较小的不影响增感染料J-聚集体的形成,而吸附较大的阻碍增感染料J-聚集形成,特别是阻光染料在增感染料之前加入乳剂中时.在氯化银微晶上吸附很小的阻光染料基本不影响增感染料对乳剂的光谱增感,而吸附较强的阻光染料不仅吸收入射光,还抑制或破坏增感染料的光谱增感.因此,在氯化银微晶表面没有吸附的阻光染料才是优良的阻光染料. 相似文献
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PAUL B. GILMAN 《Photochemistry and photobiology》1972,16(4):211-218
Abstract— Some of the important historical steps leading to our present understanding of the spectral sensitization of silver halides are reviewed and a new modification of the theory of the electron transfer mechanism of spectral sensitization is discussed. It is proposed that it is not necessary for spectral sensitizing dyes to inject electrons directly into the conduction band of the silver halide in the primary step. The only energetic restriction for the primary act of spectral sensitization is suggested to be the simple reduction of surface silver ions. However, for the spectral sensitizing act to be recorded photographically, secondary processes must be favorable for the subsequent deep trapping of the electrons that arise from the ionization of single silver atoms produced from the initial spectral sensitizing act. 相似文献
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卤化银乳剂经晶体生长、水洗、化学增感以后,还必须进行光谱增感,即加入感绿和感红的染料,以扩大卤化银乳剂微晶体对绿光和红光的光谱响应范围. 相似文献
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三氮吲哚利嗪(TAI)是一种常用的银盐感光材料的稳定剂,许多研究表明TAI在化学增感或光谱增感乳剂中具有超增感作用[1,2],另有报道,它与光谱增感染料两者之间的添加次序对增感效果有很大的影响[1,6,7]. 相似文献
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N,N'-二乙基喹啉菁染料分子吸附在硫敏化过的溴化银溶胶上产生强的表面增强喇曼散射,这种散射实际上是在直晒银上产生的。N,N'-二乙基喹啉菁染料分子吸附在硫敏化过的溴化银溶胶和银溶胶上的喇曼谱基本相似。而未经硫敏化的溴化银溶胶和经硫敏化后再被高硫酸钠氧化的溴化银溶胶中测不到N,N'-二乙基喹啉菁染料的表面增强喇曼信号。本实验进一步表明,表面增强喇曼散射方法可以用于感光机理的研究。 相似文献
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Kallay N Preočanin T Supljika F Lützenkirchen J Lovković M 《Journal of colloid and interface science》2012,375(1):167-171
The hypothesis that pH dependent charge of interfacial water affects electrokinetic charge and electrokinetic potential of hydrophobic colloids, but not the (inner) surface potential was tested. It was found that isoelectric points of silver chloride, bromide and iodide shift to the higher pAg values in the acidic solutions, but that surface potential did not depend on pH. Isoelectric points of water at inert surfaces lie in the range 2相似文献
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Conrad Siegers Jochen Hohl-Ebinger Boris Zimmermann Uli Würfel Rolf Mülhaupt Andreas Hinsch Rainer Haag 《Chemphyschem》2007,8(10):1548-1556
A new bichromophoric dyad based on an alkyl-functionalized aminonaphthalimide as energy-donor chromophore and [Ru(dcbpy)2(acac)]Cl (dcbpy=4,4'-dicarboxybipyridine, acac=acetylacetonato) as energy acceptor and sensitizing chromophore is synthesized. Efficient quenching of the donor-chromophore emission is observed in solution, presumably due to resonant energy transfer. This dyad is then used as a sensitizer in a dye solar cell. By comparing the spectral properties of transparent dye solar cells sensitized with the dyad and [Ru(dcbpy)2(acac)]Cl, it is possible to demonstrate that photons absorbed by the donor moiety also contribute significantly to the generation of current. Instead of using acceptor luminescence as a probe, enhanced photocurrent generation is employed to estimate the energy-transfer efficiency. Fitting theoretical to experimental external quantum efficiency functions gives a value for the energy-transfer efficiency of 85 %. Evaluation of the maximum output power of dye solar cells sensitized with the dyad and [Ru(dcbpy)2(acac)]Cl showed, under selective illumination at the absorption maximum of the donor chromophore, that the introduction of the energy-donor moiety leads to a significant increase in the monochromatic maximum output power under blue illumination. This result demonstrates the usefulness of energy transfer for the generation of current in dye-sensitized solar cells. 相似文献
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Dr. Eva Kirchner Dr. David Bialas Marius Wehner Dr. David Schmidt Prof. Frank Würthner 《Chemistry (Weinheim an der Bergstrasse, Germany)》2019,25(48):11285-11293
A series of three bis(merocyanine) dyes comprising chromophores of different conjugation lengths has been synthesized and the intramolecular aggregation process was investigated by UV/Vis absorption spectroscopy. The spectral changes observed upon variation of the solvent polarity reveal a folding process resulting in a cofacial π-stack of two chromophores with a decrease of the aggregation tendency with increasing chromophore length and solvent polarity. Solvent-dependent UV/Vis studies of the monomeric reference dyes show a significant increase of the polyene-like character for dyes with longer polymethine chains in nonpolar solvents, which is reversed upon aggregation due to the polarizability effect of the adjacent chromophore within the dye stack. The pronounced hypsochromic shift of the absorption band observed upon aggregation indicates strong coupling of the dyes’ transition dipole moments, which was confirmed by quantum-chemical analysis. 相似文献
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Formation of silver bromide precipitate of nanoparticles in a single microemulsion utilizing the surfactant counterion 总被引:2,自引:0,他引:2
Silver bromide precipitate of nanoparticles was prepared by addition of silver nitrate aqueous solution to a single microemulsion system consisting of dioctyldimethylammonium bromide, n-decanol, and water in isooctane. The silver ion reacted readily with the surfactant counterion, bromide, to form the precipitate of nanoparticles, which was stabilized in the water pools. The use of the surfactant counterion as a reactant is a new approach to nanoparticle preparation in microemulsions. It is characterized by high reactivity and less dependency on the intermicellar exchange of solubilizate. The effects of the surfactant and the cosurfactant concentrations, the amount of silver nitrate, and the water to surfactant mole ratio, R, were evaluated. Increasing the surfactant concentration at fixed R and amount of silver nitrate enhanced the role of intermicellar nucleation and resulted in the formation of larger particles, while increasing the amount of silver nitrate at fixed values of all the other variables enhanced the direct nucleation and resulted in the formation of smaller particles. Particle aggregation and flocculation took place when the concentration of n-decanol or the value of R was increased. Particle aggregation and flocculation were attributed to the decrease in the interaction between the surfactant protective layer and the nanoparticles in the water pools. 相似文献