Gao Yu, Guan Wei, Wang Xue-Song, Jia Ran, Yan Li-Kai, Su Zhong-Min
Institute of Functional Material Chemistry, National & Local United Engineering Lab for Power Battery, Key Laboratory of Polyoxometalate Science of Ministry of Education, Faculty of Chemistry, Northeast Normal University, Changchun 130024, P. R. China.
Laboratory of Theoretical and Computational Chemistry, Institute of Theoretical Chemistry, Jilin University, 130023 Changchun, P. R. China.
Phys Chem Chem Phys. 2020 Jul 22;22(28):16032-16039. doi: 10.1039/d0cp02449j.
The electronic properties of dyes can be readily tuned by modifying the structure. Herein, the polyoxometalate (POM)-based dyes derived from dye XW11 with new patterns, donor-acceptor-π linker-acceptor (D-A-π-A) structure (dye 1), and D-π-A-π-A structure (dye 2) were designed by inserting a POM moiety besides the extensively exploited D-π-A structure (dye 3). Based on density functional theory (DFT) and time-dependent DFT (TD-DFT) calculations, the configuration effect on the designed dyes was investigated. The results indicate that dye 3 possesses the largest short-circuit photocurrent density JSC due to the red-shifted absorption spectra, superior intramolecular charge transfer (ICT) parameters and the largest electron injection efficiency. At the same time, dye 1 with a D-A-π-A structure not only benefits the conduction band energy shift, but also retards the charge recombination and dye aggregation effect, which is beneficial for open-circuit photovoltage VOC. Moreover, the dynamics analysis of interfacial electron transfer shows that the electrons in dye 1 are almost completely injected after 14 fs, while it takes a long time for dyes 2 and 3. The present work is expected to establish a structure-property relationship for future dye design.
通过修饰结构可以很容易地调节染料的电子性质。在此，基于多金属氧酸盐（POM）的染料是由具有新结构模式的染料XW11衍生而来，通过在广泛研究的D-π-A结构（染料3）之外插入一个POM部分，设计出了供体-受体-π连接体-受体（D-A-π-A）结构（染料1）和D-π-A-π-A结构（染料2）。基于密度泛函理论（DFT）和含时密度泛函理论（TD-DFT）计算，研究了结构对所设计染料的影响。结果表明，由于吸收光谱红移、分子内电荷转移（ICT）参数优越以及电子注入效率最大，染料3具有最大的短路光电流密度JSC。同时，具有D-A-π-A结构的染料1不仅有利于导带能量的移动，还能延缓电荷复合和染料聚集效应，这对开路光电压VOC有利。此外，界面电子转移的动力学分析表明，染料1中的电子在14 fs后几乎完全注入，而染料2和染料3则需要很长时间。目前的工作有望为未来的染料设计建立结构-性能关系。
