Jiao Fangfang, Wei Mingzhi, Leng Jiancai, Cui Min, Liu Ziyu, Hu Wei, Zhang Yujin
Shandong Provincial Key Laboratory of Molecular Engineering, School of Chemistry and Chemical Engineering, Qilu University of Technology (Shandong Academy of Sciences), 250353, Jinan, Shandong, P. R. China.
School of Materials Science & Engineering, Qilu University of Technology (Shandong Academy of Sciences), 250353, Jinan, Shandong, P. R. China.
Chem Asian J. 2022 May 2;17(9):e202200075. doi: 10.1002/asia.202200075. Epub 2022 Mar 29.
The introduction of a self-adaptive molecular switch is an appealing strategy to achieve complete charge separation (CS) in donor-acceptor (D-A) systems. Here, we designed donor-switch-acceptor (D-S-A) systems using a platinum(II) terpyridyl complex as the acceptor, dimethyldihydropyrene/cyclophanediene (DHP/CPD) as the bridge, and methoxybenzene, thieno[3,2-b]thiophene, 2,2'-bifuran, and 4,8-dimethoxybenzo[1,2-b:4,5-b']difuran as donors, respectively. We then systematically studied the whole opto-electronic conversion process of the donor-DHP/CPD-acceptor (D-DHP/CPD-A) systems based on time-dependent density functional theory, time-dependent ultrafast electron evolution, and electron transport property calculations. We first found that the substitution of -CH by -H and -CN groups in DHP/CPD can enlarge the range of the adsorption wavenumber in opto-electric conversion. Then the light absorption induces the cationization of DHP switch, largely accelerating the forth-isomerization to CPD form. Once the D-CPD-A molecule is formed, the poor conjugation can realize the complete CS state by inhibiting the radiative and nonradiative charge recombinations. Finally, the repeatable and complete CS can be achieved through the automatic back-isomerization of CPD to DHP. The present work provides valuable insights into design of D-S-A systems for practical utilization of molecule-based solar harvesting.
引入自适应分子开关是在供体-受体（D-A）体系中实现完全电荷分离（CS）的一种有吸引力的策略。在此，我们设计了供体-开关-受体（D-S-A）体系，分别以铂（II）三联吡啶配合物作为受体，二甲基二氢芘/环番二烯（DHP/CPD）作为桥连基团，以及甲氧基苯、噻吩并[3,2-b]噻吩、2,2'-联呋喃和4,8-二甲氧基苯并[1,2-b:4,5-b']二呋喃作为供体。然后，我们基于含时密度泛函理论、含时超快电子演化和电子输运性质计算，系统地研究了供体-DHP/CPD-受体（D-DHP/CPD-A）体系的整个光电转换过程。我们首先发现，在DHP/CPD中用-H和-CN基团取代-CH可扩大光电转换中吸附波数的范围。然后光吸收诱导DHP开关阳离子化，极大地加速向CPD形式的正向异构化。一旦形成D-CPD-A分子，较差的共轭作用可通过抑制辐射和非辐射电荷复合实现完全CS状态。最后，通过CPD自动反向异构化为DHP可实现可重复的完全CS。本工作为基于分子的太阳能收集实际应用中D-S-A体系的设计提供了有价值的见解。
