Department of Chemistry - Ångström Laboratory, Uppsala University , Box 523, 75120 Uppsala, Sweden.
J Am Chem Soc. 2016 Jul 6;138(26):8060-3. doi: 10.1021/jacs.6b03889. Epub 2016 Jun 23.
The combination of molecular dyes and catalysts with semiconductors into dye-sensitized solar fuel devices (DSSFDs) requires control of efficient interfacial and surface charge transfer between the components. The present study reports on the light-induced electron transfer processes of p-type NiO films cosensitized with coumarin C343 and a bioinspired proton reduction catalyst, FeFe(CO)6 (mcbdt = 3-carboxybenzene-1,2-dithiolate). By transient optical spectroscopy we find that ultrafast interfacial electron transfer (τ ≈ 200 fs) from NiO to the excited C343 ("hole injection") is followed by rapid (t1/2 ≈ 10 ps) and efficient surface electron transfer from C343(-) to the coadsorbed FeFe(CO)6. The reduced catalyst has a clear spectroscopic signature that persists for several tens of microseconds, before charge recombination with NiO holes occurs. The demonstration of rapid surface electron transfer from dye to catalyst on NiO, and the relatively long lifetime of the resulting charge separated state, suggests the possibility to use these systems for photocathodes on DSSFDs.
将分子染料和催化剂与半导体结合到染料敏化太阳能燃料器件 (DSSFD) 中，需要控制组件之间有效的界面和表面电荷转移。本研究报告了 p 型 NiO 薄膜的光诱导电子转移过程，该薄膜同时敏化了香豆素 C343 和一种仿生质子还原催化剂 FeFe(CO)6（mcbdt = 3-羧基苯-1,2-二硫醇）。通过瞬态光学光谱，我们发现超快的界面电子转移（τ≈200fs）从 NiO 到激发态的 C343（“空穴注入”），然后是快速（t1/2≈10ps）和有效的表面电子从 C343(-)转移到共吸附的 FeFe(CO)6。还原后的催化剂具有明确的光谱特征，持续数十微秒，然后与 NiO 空穴发生电荷复合。从染料到 NiO 上催化剂的快速表面电子转移的证明，以及由此产生的电荷分离态的相对长寿命，表明这些体系有可能用于 DSSFD 的光电阴极。
