Pinjari Dilip, Alsaleh Ajyal Z, Patil Yuvraj, Misra Rajneesh, D'Souza Francis
Department of Chemistry, Indian Institute of Technology, Indore, 453552, India.
Department of Chemistry, University of North Texas, 1155 Union Circle, #305070, Denton, TX, 76203-5017, USA.
Angew Chem Int Ed Engl. 2020 Dec 21;59(52):23697-23705. doi: 10.1002/anie.202013036. Epub 2020 Nov 18.
Push-pull systems comprising of triphenylamine-tetracyanobutadiene (TPA-TCBD), a high-energy charge-transfer species, are linked to a near-IR sensitizer, azaBODIPY, for promoting excited-state CS. These systems revealed panchromatic absorption owing to intramolecular CT and near-IR absorbing azaBODIPY. Using electrochemical and computational studies, energy levels were established to visualize excited state events. Fs-TA studies were performed to monitor excited state CT events. From target analysis, the effect of solvent polarity, number of linked CT entities, and excitation wavelength dependence in governing the lifetime of CS states was established. Electron exchange between two TPA-TCBD entities in 3 seem to prolong lifetime of the CS state. We have been successful in demonstrating efficient CS upon both high-energy CT and low-energy near-IR excitations, signifying importance of these push-pull systems for optoelectronic applications operating in the wide optical window.
由三苯胺 - 四氰基丁二烯（TPA - TCBD，一种高能电荷转移物种）组成的推挽系统与近红外敏化剂氮杂BODIPY相连，以促进激发态电荷转移（CS）。由于分子内电荷转移和近红外吸收的氮杂BODIPY，这些系统呈现出全色吸收。通过电化学和计算研究，确定了能级以可视化激发态事件。进行了飞秒瞬态吸收（Fs - TA）研究以监测激发态电荷转移事件。通过目标分析，确定了溶剂极性、连接的电荷转移实体数量以及激发波长依赖性对电荷转移态寿命的影响。3中两个TPA - TCBD实体之间的电子交换似乎延长了电荷转移态的寿命。我们成功地证明了在高能电荷转移和低能近红外激发下都能实现高效的电荷转移，这表明这些推挽系统对于在宽光学窗口中运行的光电子应用具有重要意义。
