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首页> 外文期刊>The journal of physical chemistry, A. Molecules, spectroscopy, kinetics, environment, & general theory >2]2+–TiO2 and [Fe(cCNC)2]2+–TiO2 Assemblies: Importance of Conformational Sampling]]>
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2]2+–TiO2 and [Fe(cCNC)2]2+–TiO2 Assemblies: Importance of Conformational Sampling]]>

机译：<！[CDATA [CDATA [FE（CTPY） 2 ] 2 + -tio 2 和[fe（ccnc ） 2 ] 2 + -tio 2 程序集：构象采样的重要性]]>

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Fe(II)–polypyridines have limited applications as chromophores in dye-sensitized solar cells due to the short lifetimes (～100 fs) of their photoactive metal-to-ligand charge transfer (MLCT) states formed upon photoexcitation. Recently, a 100-fold increase in the MLCT lifetime was observed in a [Fe(CNC)_(2)]~(2+) complex (CNC = 2,6-bis(3-methylimidazole-1-ylidine)pyridine) which has strong σ-donating N -heterocyclic carbene ligand in comparison to the weaker field parent [Fe(tpy)_(2)]~(2+) complex (tpy = 2,2′:6′,2″-terpyridine). This study utilizes density functional theory (DFT), time-dependent DFT, and quantum dynamics simulations to investigate the interfacial electron transfer (IET) in [Fe(cCNC)_(2)]~(2+) (cCNC = 4′-carboxy-2,6-bis(3-methylimidazole-1-ylidine)pyridine) and [Fe(ctpy)_(2)]~(2+) (ctpy = 4′-carboxy-2,2′:6′,2″-terpyridine) sensitized TiO_(2). Our results suggest that the replacement of tpy by CNC ligand does not significantly speed up the IET kinetics in the [Fe(cCNC)_(2)]~(2+)–TiO_(2) assembly in comparison to the [Fe(ctpy)_(2)]~(2+)–TiO_(2) analogue. The high IET efficiency in the [Fe(cCNC)_(2)]~(2+)–TiO_(2) assemblies is therefore due to longer lifetime of [Fe(cCNC)_(2)]~(2+) photoactive ~(3)MLCT states rather than faster electron injection kinetics. It was also found that the inclusion of conformational sampling in the computational model is important for proper description of the IET processes in these systems, as the models relying on the use of only fully optimized structures may yield misleading results. The simulations presented in this work also illustrate various pitfalls of utilizing properties such as electronic coupling, number of available acceptor states, and driving force, as well as calculations based on Fermi’s golden rule framework, to reach conclusions on the IET efficiency in dye–semiconductor systems.
机译：的Fe（II）-polypyridines具有有限的应用，在染料敏化太阳能电池的发色团由于它们的光活性金属 - 配体电荷转移（MLCT）的寿命短（〜100个FS）在光激发各州形成。最近，在未观察到MLCT寿命的100倍的增加的[Fe（CNC）_（2）]〜（2+）络合物（CNC = 2,6-双（3-甲基咪唑-1-亚基）吡啶）具有很强的σ供ñ - 杂环卡宾配体相比，较弱的磁场父的[Fe（TPY）_（2）]〜（2+）络合物（TPY = 2,2'：6'，2“ - 三联吡啶） 。该研究利用密度泛函理论（DFT），依赖于时间的DFT，以及量子动力学模拟来调查的[Fe（CCNC）_（2）]〜（2+）（CCNC = 4'-的界面的电子转移（IET）羧基-2,6-双（3-甲基咪唑-1-亚基）吡啶）和[Fe（上ctpy）_（2）]〜（2+）（ctpy = 4'-羧基-2,2'：6'， 2“ - 三联吡啶）致敏TiO_（2）。我们的研究结果表明，通过CNC更换万吨的配体不显著加快在所述IET动力学的[Fe（CCNC）_（2）]〜（2 +） - TiO_（2）组件相比于的[Fe（ctpy ）_（2）]〜（2 +） - TiO_（2）类似物。在高效率IET的[Fe（CCNC）_（2）]〜（2 +） - TiO_（2）组件因此是由于的[Fe（CCNC）_（2）]的更长的寿命〜（2+）的光活性〜（3）MLCT指出，而不是更快电子注入动力学。有人还发现，构象采样的计算模型中包含对这些系统的IET过程的正确描述重要的，因为模型依赖于使用唯一的完全优化的结构可能会产生误导的结果。在这项工作中呈现的模拟还示出了使用性能，例如电子耦合，可用的受主态的数目，和驱动力，以及计算基于费米黄金定则框架，以在染料半导体的IET效率得出结论的各种陷阱系统。

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