Bertocchi Francesco, Delledonne Andrea, Vargas-Nadal Guillem, Terenziani Francesca, Painelli Anna, Sissa Cristina
Dipartimento di Scienze Chimiche, della Vita e della Sostenibilità Ambientale, Università di Parma, Parco Area delle Scienze 17A, 43124, Parma, Italy.
J Phys Chem C Nanomater Interfaces. 2023 May 18;127(21):10185-10196. doi: 10.1021/acs.jpcc.3c01253. eCollection 2023 Jun 1.
Aggregates of cyanine dyes are currently investigated as promising materials for advanced electronic and photonic applications. The spectral properties of aggregates of cyanine dyes can be tuned by altering the supramolecular packing, which is affected by the length of the dye, the presence of alkyl chains, or the nature of the counterions. In this work, we present a joint experimental and theoretical study of a family of cyanine dyes forming aggregates of different types according to the length of the polymethinic chain. Linear and nonlinear optical spectra of aggregates are rationalized here in terms of an essential-state model accounting for intermolecular interactions together with the molecular polarizability and vibronic coupling. A strategy is implemented to properly account for screening effects, distinguishing between electrostatic intermolecular interactions relevant to the ground state (mean-field effect) and the interactions relevant to the excited states (excitonic effects). To the best of our knowledge, this is the first attempt to simulate nonlinear spectral properties of aggregates of symmetric dyes accounting for molecular vibrations.
目前，花菁染料聚集体作为先进电子和光子应用的有前景材料正在被研究。花菁染料聚集体的光谱性质可通过改变超分子堆积来调节，而超分子堆积受染料长度、烷基链的存在或抗衡离子的性质影响。在这项工作中，我们对一族根据聚甲炔链长度形成不同类型聚集体的花菁染料进行了联合实验和理论研究。这里，聚集体的线性和非线性光谱根据一个考虑分子间相互作用以及分子极化率和振动耦合的本征态模型进行了合理解释。实施了一种策略来恰当考虑屏蔽效应，区分与基态相关的静电分子间相互作用（平均场效应）和与激发态相关的相互作用（激子效应）。据我们所知，这是首次尝试模拟考虑分子振动的对称染料聚集体的非线性光谱性质。
