Department of Applied Chemistry, Kyushu University, 744 Motooka, Fukuoka 8190395, Japan.
Phys Chem Chem Phys. 2011 Oct 28;13(40):18031-7. doi: 10.1039/c1cp22425e. Epub 2011 Sep 15.
Artificial photosynthesis is one of the chemists' dreams and the separation of charges with long lives is fundamental for achieving artificial photosynthesis. In actual photosynthesis, Z-scheme excitation separates electronic charge with high efficiency using solar light. Here we report that photo-excitation in Cr-tetraphenylporphyrin chroride (Cr-TPPCl)/Zr doped KTaO(3) (KTa(Zr)O(3)) is analogous to the Z-scheme in photosynthesis, and that we achieve complete charge separation at room temperature. Photovoltaic decay and transient fluorescence spectra measurements showed that the photo-excited charge in KTa(Zr)O(3) transferred to the HOMO of Cr-TPPCl within a few hundred pico-seconds on charge transfer. In contrast, the reduced state of the Cr-TPPCl species that was formed by the electronic injection from KTa(Zr)O(3) was observed for more than 0.5 s at room temperature in the transient decay of the absorption spectra change after the initial excitation of KTa(Zr)O(3). The formed reduced state of Cr-TPPCl was highly stable and was detected by static ESR measurements.
人工光合作用是化学家的梦想之一，而长寿命的电荷分离是实现人工光合作用的基础。在实际的光合作用中，Z 型激发利用太阳光高效地分离电子电荷。在这里，我们报告说，Cr-四苯基卟啉氯化物（Cr-TPPCl）/Zr 掺杂 KTaO(3)（KTa(Zr)O(3)）中的光激发类似于光合作用中的 Z 型激发，并且我们在室温下实现了完全的电荷分离。光伏衰减和瞬态荧光光谱测量表明，在电荷转移过程中，KTa(Zr)O(3)中的光激发电荷在几百皮秒内转移到 Cr-TPPCl 的 HOMO。相比之下，在 KTa(Zr)O(3)的初始激发后，吸收光谱变化的瞬态衰减中，在室温下观察到 Cr-TPPCl 物种的还原态形成超过 0.5 秒。形成的 Cr-TPPCl 还原态非常稳定，并通过静态 ESR 测量检测到。
