Distance dependence of heterogeneous electron transfer probed in ultra-high vacuum with femtosecond transient absorption
Distance dependence of heterogeneous electron transfer probed in ultra-high vacuum with femtosecond transient absorption
复制标题
利用飞秒瞬态吸收探测超高真空中异质电子转移的距离依赖性
DOI：
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发表时间：
2005
期刊：
影响因子：
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通讯作者：
F. Willig
中科院分区：
文献类型：
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作者：
R. Ernstorfer;S. Felber;W. Storck;E. Galoppini;Q. Wei;F. Willig
在超高真空条件下，利用飞秒暂态吸收光谱研究了分子发色团茂分子的单重态电子注入宽禁带半导体二氧化钛的过程。生色团结合到饱和的间隔基和锚基上。后者在纳米结构的锐钛矿型TiO2层表面形成键。后一步的制备和FS-TA测量都是在可以容纳溶剂的特殊超高真空室中进行的。速率常数是在所谓的宽带限制情况下测量的，在这种情况下，它们只受电子耦合强度控制，而不受Franck-Condon因子控制。对不同饱和锚定和间隔基的测量表明，反应速率常数与反应距离呈指数关系。在超高真空中，距离参数为0.1 nm。测得羧基锚基的最短注射时间为13ps，长刚性所谓的三脚架锚定间隔基的最长注射时间为4ps。
Electron injection from the excited singlet state of the molecular chromophore perylene into the wide-band-gap semiconductor TiO2 was investigated in ultra-high vacuum employing femtosecond transient absorption (fs-TA) spectroscopy. The chromophores were bound to saturated spacer-cum-anchor groups. The latter formed bonds on the surface of nm-structured anatase TiO2 layers. Both the latter preparation step and the fs-TA measurements were performed in a special ultra-high-vacuum chamber that can accommodate solvents. The rate constants were measured in the so-called wide band limiting case where they are controlled only by the electronic coupling strength and not by Franck–Condon factors. Measurements with different saturated anchor-cum-spacer groups revealed an exponential dependence of the rate constants on the reaction distance. The distance parameter was 0.1 nm in ultra-high-vacuum. The shortest injection time of 13 fs was measured for the carboxyl anchor group and the longest of 4 ps for the long rigid so-called tripod anchor-cum-spacer group.