共查询到17条相似文献,搜索用时 109 毫秒
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硫增感AgBrI T颗粒乳剂光电子行为研究 总被引:3,自引:1,他引:3
利用微波相敏技术,获得了硫增感AgBrI T颗粒乳剂中自由光电子和束缚光电子时间衰减信号,分析了光电子衰减时间、电子陷阱效应、光电子寿命、有效陷阱深度及束缚电子转移时间与增感时间的关系,获得了最佳的增感时间、衰减时间、电子陷阱效应、光电子寿命、有效陷阱深度和转移时间数值, 相似文献
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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. 相似文献
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曝光强度对卤化银微晶中载流子行为及其陷阱效应的影响 总被引:3,自引:0,他引:3
针对卤化银感光材料潜影形成过程中光作用动力学问题,分析了曝光强度对光生载流子行为和电子陷阱效应的影响,认为伴随着曝光强度的增加,影响光电子衰减的因素由电子陷阱起主要作用演化到电子陷阱和复合中心共同起作用进而演化到复合中心起主要作用. 相似文献
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染料增感AgBr乳剂的光电子衰减动力学研究 总被引:2,自引:0,他引:2
本工作利用微波吸收薄膜介电谱测量技术,测量了菁染料光谱增感后的AgBr晶体乳剂在脉冲激光曝光后产生的光电子衰减时间特性,分析了不同类型的染料及其增感条件对材料光电子时间特性的影响关系.通过比较增感后的T-颗粒乳剂和立方体乳剂的光电子衰减特性,实验验证了吸附在T-颗粒(111)晶面上的染料比吸附在立方体(100)晶面上的染料更有效、更有助于形成潜影的论据. 相似文献
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硫增感AgBr I T颗粒乳剂光电子行为研究 总被引:1,自引:1,他引:1
本文利用微波吸收相敏检测技术,同时获得了硫增感AgBrIT颗粒乳剂,在不同增感条件下自由光电子和浅俘获光电子的时间衰减曲线,分析了不同的硫增感产物的陷阱效应.结果表明:开始时,增感产物起电子陷阱作用,至45min时,浅电子陷阱作用最佳.如增感时间进一步增加,硫增感产物将变为深电子陷阱.本文还讨论了浅电子陷阱中浅俘获光电子衰减时间与阱深的依存关系. 相似文献
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溴碘化银核壳乳剂中电子的捕获和复合 总被引:2,自引:0,他引:2
本文应用双注仪制备了在核表面进行不同程度还原增感和一系列溴碘化银核壳乳剂,在没条件下测定了核表面形成的不同还原增感中心对乳剂微晶光电子衰减动力学及发光光谱的影响。结果表明:在一定增感温度和时间条件下,当Na2SO3用量低于5.4mg/molAg时光电子衰减动力学为二级反应,而当Na2SO3用量超过27mg/molAg时,增感中心一部分作为穴陷阱,另一部分作为电子陷阱,光电子衰减速率决定了电子的捕获 相似文献
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本文利用微波吸收相敏检测技术 ,同时获得了立方体AgBrCl乳剂中 ,在增感温度增加的条件下 ,自由光电子和浅束缚光电子的时间衰减曲线 ,分析了不同的硫增感产物随增感温度增加所起的陷阱效应。结果表明 ,在立方体AgBrCl乳剂中 ,硫增感初始阶段的增感产物主要是作为浅电子陷阱存在 ;随着增感温度增加至5 5℃时 ,增感产物浅电子陷阱效果最佳 ;如增感温度进一步增加 ,硫增感中心又变为深电子陷阱。文中还讨论了浅电子陷阱中浅束缚光电子衰减时间与阱深的依存关系。 相似文献
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Preparation and thermal degradation behavior of room temperature vulcanized silicone rubber-g-polyhedral oligomeric silsesquioxanes 总被引:1,自引:0,他引:1
Room temperature vulcanized (RTV) silicone rubber-g-polyhedral oligomeric silsesquioxanes (POSS) was prepared and its thermal degradation behavior and thermo-oxidative stability were investigated by thermogravimetric analysis (TGA). The results demonstrated that the chemical incorporation of POSS into polydimethylsiloxane (PDMS) chains significantly enhanced thermal stability of RTV silicon rubber in both nitrogen and air atmosphere. The degradation behavior was further monitored by TGA coupled with real time Fourier transform infrared spectra (FTIR), and the residues were characterized by FTIR and X-ray photoelectron spectroscopy (XPS). It was found that the remarkable improvement in thermal stability could be attributed to the following reasons: (1) the branched structure of RTV silicone rubber-g-POSS and interaction between POSS molecules and PDMS chains; (2) POSS traps generated and grafted or cross-linked structure formed; (3) intumescent ceramic protective barrier formed; (4) the perfect distribution of POSS in RTV silicone rubber-g-POSS. 相似文献
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A study of the dynamics of the electronic states of CdS semiconductor clusters grown in situ in reversed micelles via picosecond pump-probe technique reveals efficient transient bleaching of the excitonic absorption. This effect is attributable mainly to hole localization near the trapped electron, with no evidence of electron ejection (forming a solvated electron) detectable despite the apparent proximity of the cluster to the included water pool. Bleaching efficiency is cluster-size dependent, and recovery kinetics are governed by the nature of the particle surface. Similar decay behavior is observed in cluster fluorescence. Generally, the decay is characterized by two components, the faster attributed to recombination of a mobile, detrapped electron with a trapped hole, and the slower to an exchange interaction between trapped carriers. The observed strong multiexponentionality of the decay results from a distribution in trap energy levels, as well as from a distribution of distances between traps on the cluster surface. By varying preparation conditions, particles of different sizes with different surface defects can be grown in reversed micelles in a reproducible way so that their electronic properties can be controlled. 相似文献
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继前文的潜影形成模型,对化学增感乳剂进行了计算机模拟研究。结果如下:(1)硫增感引入大的浅陷阱,可增加敏度与改善低照互易律失效;其空穴陷阱的作用则不是很有效。(2)金增感除了减小可显影中心的尺寸和增加抗氧化能力外,还应有另外的增感机理。Ag_2经金强化可以部分地转化为可显影中心。(3)还原增感斑与尺寸相同的曝光产生的银斑性质相同,曝光时大部分还原增感斑被破坏掉了,只有极少数有机会长大。还原增感斑的两个重要作用:提高了形成潜影的概率;消耗空穴或光解溴,使颗粒中的净剩电子增多。二者对潜影形成都有重要贡献。 相似文献
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Michael Filatov Seunghoon Lee Hiroya Nakata Cheol-Ho Choi 《International journal of molecular sciences》2021,22(8)
The non-adiabatic dynamics of furan excited in the ππ* state (S2 in the Franck–Condon geometry) was studied using non-adiabatic molecular dynamics simulations in connection with an ensemble density functional method. The time-resolved photoelectron spectra were theoretically simulated in a wide range of electron binding energies that covered the valence as well as the core electrons. The dynamics of the decay (rise) of the photoelectron signal were compared with the excited-state population dynamics. It was observed that the photoelectron signal decay parameters at certain electron binding energies displayed a good correlation with the events occurring during the excited-state dynamics. Thus, the time profile of the photoelectron intensity of the K-shell electrons of oxygen (decay constant of 34 ± 3 fs) showed a reasonable correlation with the time of passage through conical intersections with the ground state (47 ± 2 fs). The ground-state recovery constant of the photoelectron signal (121 ± 30 fs) was in good agreement with the theoretically obtained excited-state lifetime (93 ± 9 fs), as well as with the experimentally estimated recovery time constant (ca. 110 fs). Hence, it is proposed to complement the traditional TRPES observations with the trXPS (or trNEXAFS) measurements to obtain more reliable estimates of the most mechanistically important events during the excited-state dynamics. 相似文献
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Anu Mishra 《应用聚合物科学杂志》1982,27(6):1967-1975
Charge stabilities of various polar polymer homoelectrets were determined. Although these electerts are reasonably stable in dry environments, they rapidly discharge when exposed to humidity. The rate of charge decay was found to depend directly on the ability of these polymers to absorb water under equilibrium conditions. Protection from humidity is obtained if these polar polymers are coated on both sides with nonpolar polymers. If, however, two different polymer films are laminated, the electret behavior follows a pattern that can be explained on the basis of charging at the interface. Difference in stabilities of the electrets of polar and nonpolar polymers is attributed to the differing natures of the charge traps present in these two classes of polymers. 相似文献