Zipper assembly of SHJ photosystems: focus on red naphthalenediimides, optoelectronic finetuning and topological matching
Zipper assembly of SHJ photosystems: focus on red naphthalenediimides, optoelectronic finetuning and topological matching
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DOI：
10.1039/c0sc00177e
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发表时间：
2010-09-01
期刊：
影响因子：
8.4
通讯作者：
Matile, Stefan
中科院分区：
文献类型：
--
作者：
Bhosale, Rajesh;Kishore, Ravuri S. K.;Matile, Stefan
本研究以非卤代红（R-O）萘二酰亚胺（ndi）为载体，沿对低聚苯基（POP）和低聚苯基乙基（OPE）为支架，合成多色给受体体系，并评价其在人工光系统拉链组装中的应用价值。与卤化红色ndi （R-Cl, R-Br）相比，R-O的HOMO高0.2 eV， HOMO/LUMO隙小0.1 eV，后者引入了粉红色的阴影。与较高的HOMO能级一致，R-O拉链在各自的作用光谱中产生的光电流比R-Br拉链少。R-O拉链对拓扑不匹配的敏感性低于R-Br拉链，因此更坚固，适用范围更广。瞬态吸收测量表明，从激发的OPE供体到R-O受体的电子转移是有效的，而从激发的R-O供体到OPE受体的空穴注入效率较低。这两种工艺都证明了与OMARG-SHJ光系统（具有定向多色反平行氧化还原梯度的超分子n/p异质结）的兼容性。随着HOMO能量差的减小，空穴转移的减少进一步表明shj型空穴注入是逐渐消失的（而不是突然消失的）。在此过程中，光子能量的损失可以通过光电微调最小化，但最终开路电压的增益有可能伴随着短路电流的补充损失。
The objective of this study was to synthesize multichromophoric donor-acceptor systems with non-halogenated red (R-O) naphthalenediimides (NDIs) attached along p-oligophenyl (POP) and oligophenylethynyl (OPE) scaffolds, and to evaluate their usefulness for zipper assembly of artificial photosystems. Compared to halogenated red NDIs (R-Cl, R-Br), the HOMO of R-O is 0.2 eV higher and the HOMO/LUMO gap 0.1 eV smaller, the latter introducing a shade of pink. Consistent with higher HOMO levels, R-O zippers generate less photocurrent than R-Br zippers in their respective action spectra. R-O zippers are less sensitive to topological mismatch than R-Br zippers and thus more robust and broadly applicable. Transient absorption measurements reveal efficient electron transfer from excited OPE donors to R-O acceptors and less efficient hole injection from excited R-O donors into OPE acceptors. Both processes demonstrate compatibility with OMARG-SHJ photosystems (supramolecular n/p-heterojunctions with oriented multicolored antiparallel redox gradients). Decreasing hole transfer with decreasing HOMO energy differences further demonstrates that SHJ-type hole injection disappears gradually (rather than abruptly). Losses in photonic energy during this process can thus be minimized by optoelectronic finetuning, but eventual gains in open circuit voltages risk coming with complementary losses in short circuit current.