Observing the Fluctuation Dynamics of Dative Bonds Using Two-Dimensional Electronic Spectroscopy

Characterization of the ultrafast spectral diffusion and vibronic coherence of TIPS-pentacene using 2D electronic spectroscopy

“…62,63 We also note that we did not observe any substantial dynamics at Tw > 10 ps timescale, which are usually ascribed to various intermolecular interactions. 27,28,64 Some molecular systems exhibit spectral diffusion dynamics at this slow timescale (tens to hundreds of ps) due to stronger interactions with the solvents. Examples include chlorophyll-like systems that undergo hydrogen-bonding 27,64 or ligation dynamics between nucleophilic solvent molecules and the metal center of chlorophylls.…”

“…Examples include chlorophyll-like systems that undergo hydrogen-bonding 27,64 or ligation dynamics between nucleophilic solvent molecules and the metal center of chlorophylls. 28 In the case of TIPS-Pn, the absence of a lifetime longer than 10 ps suggests that the optical transition of the molecule is likely insensitive to solvation dynamics of nonpolar solvents. In our study, there is also no constant offset or ns timescale decay, suggesting that there is negligible structural inhomogeneity in the system.…”

“…24 One analysis method that is commonly used is the center line slope (CLS) analysis. 25,26 CLS analysis of spectral diffusion has been performed on several systems, such as photosynthetic pigments, 27,28 quantum dots, 29 biological molecules, 30 and reverse micelles, 31 which provided crucial information regarding how the environment interacts with these systems and affects their spectroscopic properties. Apart from the FFCF decay, coherent modulations of the transition can also be tracked using CLS analysis.…”

Measuring the Ultrafast Spectral Diffusion and Vibronic Coupling Dynamics in CdSe Colloidal Quantum Wells using Two-Dimensional Electronic Spectroscopy

“…This can be based on a theoretical framework relying on diagrammatic time-dependent perturbation theory, Kubo line shape theory, and Brownian oscillator model. 28,47 Conversely, measuring the ultrafast spectral diffusion dynamics and FFCF provide insights into these couplings at the atomic and molecular level 48 and allow us to formulate appropriate mechanisms for understanding and optimizing various properties important in such CdSe NPL systems.…”

“…Excitonic coupling and energy transfers are the typical processes that can be directly observed in 2DES, as has been applied to several previous studies on various complex systems. ,,− In addition, one phenomenon that can be measured in 2DES but is inaccessible using conventional TA spectroscopy is ultrafast spectral diffusion, which dictates the evolution of the 2D peakshapes due to the ability of 2DES to correlate the excitation and detection frequencies . In ultrafast spectral diffusion, the excited system fluctuates and evolves to different frequencies in the time scale of femtoseconds to picoseconds due to interactions of the system with the environment, including coupling to vibrations of the proteins and/or solvent molecules in the environment as well as lattice phonon modes. − These ultrafast spectral diffusions take place at a much shorter time scale of the spectral diffusion measured by single-molecule PL studies on nanocrystals, which are at time scales of milliseconds to seconds. − One measure of the ultrafast spectral diffusion dynamics of an ensemble is the frequency-fluctuation correlation function (FFCF). ,, FFCF is a useful quantity as it connects microscopic molecular and atomic level dynamics directly to the nonlinear optical spectroscopic measurements such as 2DES. This can be based on a theoretical framework relying on diagrammatic time-dependent perturbation theory, Kubo line shape theory, and Brownian oscillator model. , Conversely, measuring the ultrafast spectral diffusion dynamics and FFCF provide insights into these couplings at the atomic and molecular level and allow us to formulate appropriate mechanisms for understanding and optimizing various properties important in such CdSe NPL systems.…”