Institute of Physical and Theoretical Chemistry, Goethe-University, Max-von-Laue-Strasse 7, D-60438 Frankfurt/Main, Germany.
J Phys Condens Matter. 2012 Oct 3;24(39):394007. doi: 10.1088/0953-8984/24/39/394007. Epub 2012 Sep 11.
The photoinduced dynamics of a dithienylethene chromophore coupled to the surface of TiO(2) by either a tripodal linker or a carboxyl group was investigated with ultrafast transient absorption spectroscopy. The absence of electron transfer from the photoexcited tripodal dithienylethene chromophore demonstrates that the tripod efficiently uncouples the electronic systems of dithienylethene and TiO(2). Contrary to this situation, photoinduced electron transfer can compete with ultrafast intramolecular relaxation in the COOH-dithienylethene/TiO(2) coupled system. An electron transfer rate of 1.1 × 10(12) s(-1) can be extracted, which is considerably slower than the intramolecular relaxation rate of the dithienylethene (3.7 × 10(12) s(-1)). Consequently, the electron transfer reaction exhibits a low efficiency.
用超快瞬态吸收光谱研究了通过三脚架连接体或羧基连接到 TiO(2)表面的二噻吩乙烯发色团的光诱导动力学。从光激发的三脚架二噻吩乙烯发色团中没有观察到电子转移，这表明三脚架有效地使二噻吩乙烯和 TiO(2)的电子系统解耦。与此相反，在 COOH-二噻吩乙烯/TiO(2)偶联体系中，光诱导电子转移可以与超快分子内松弛竞争。可以提取出 1.1×10(12)s(-1)的电子转移速率，这明显慢于二噻吩乙烯的分子内松弛速率(3.7×10(12)s(-1))。因此，电子转移反应的效率较低。
