Progress on Exploring the Luminescent Properties of Organic Molecular Aggregates by Multiscale Modeling

Zhao, Jingyi; Zheng, Xiaoyan

doi:10.3389/fchem.2021.808957

Cited by 7 publications

(6 citation statements)

References 82 publications

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“…Given that k ic is a crucial factor for determining the FQE of DBTS and Cz crystals, we next evaluated the roles of the main excited-state energy dissipation ways in the internal conversion process: electron–vibration coupling and non-adiabatic electronic coupling. The strength of electron–vibration coupling is measured by reorganization energy (λ). − The total reorganization energy (λ total ) is the summation of reorganization energies at the ground state (λ gs ) and excited state (λ es ). The non-adiabatic electronic coupling strength is quantified by the diagonal element of the electronic coupling matrix R kk .…”

Section: Resultsmentioning

confidence: 99%

Conformational Flexibility-Controlled Piezochromic Behavior of Organic Fluorophores

2022

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The pressure-responsive behaviors of organic fluorophores are often irregular and highly system-dependent. Unraveling the pressure effects on them is the key to the precise design of piezochromic materials. Here, we demonstrate that the different conformational flexibilities of organic fluorophores can lead to their distinct piezochromic behaviors. By combining quantum mechanics/molecular mechanics models and thermal vibration correlation function formalism, we show that two organic fluorophores, dibenzo[b,d]thiophene 5,5-dioxide (DBTS) and carbazole (Cz), with similar chemical structures, display different conformations and conformational flexibilities, which determine the responsiveness of their piezochromic behaviors. It is found that pressurization continuously improves the planarity between the sulfonyl group and the aromatic skeleton in cross-shaped DBTS, leading to red-shifted emission. In addition, the fluorescence quantum efficiency (FQE) of DBTS increases monotonically in a wide range of 0−7 GPa and then shows a dramatic reduction upon further compression to 12 GPa. The non-monotonical FQE of DBTS is attributed to the continuously decreased radiative decay rate constant (k r ) and non-monotonically changed non-radiative decay rate constant (k ic ). The initial decrease in k ic is due to the restriction of aromatic skeleton vibrations in the high-frequency region, and the subsequent increase in k ic is ascribed to the acceleration of the bending and rotational vibrations of the sulfonyl group in the low-frequency region. In contrast, pressurization hardly influences the conformation of planar Cz, resulting in a slight change in emission and FQE, which is well consistent with experimental results. This study opens an efficient shortcut to the rational design of advanced piezochromic luminescent materials.

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Section: Resultsmentioning

confidence: 99%

Conformational Flexibility-Controlled Piezochromic Behavior of Organic Fluorophores

2022

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“…73,74,[78][79][80][81][82][83][84][85] Finally, we mention that the structures are sensitive to the environments, such as presence of other ligands, 86 and aggregation. [87][88][89][90][91][92][93][94][95][96][97] The suitability of these molecules in the application of solar cells and compatibility with the acceptors 84,[98][99][100][101][102][103][104][105][106] for electron transport will need detailed electronic properties, which are discussed below.…”

Section: Scheme 2 the Synthesis Of Cis Indoline Structure Scheme 3 St...mentioning

confidence: 99%

Tuning the HOMO Energy of the Triarylamine Molecules with Orthogonal HOMO and LUMO Using Functional Groups

Zhuang

Amaro

Testoff

et al. 2023

Preprint

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Tuning the HOMO and LUMO energy strategically of triphenylamine derivatives plays an important role towards understanding and design of high performance organic photovoltaics. To improve on the charge separation and electron transfer properties, twenty one D-pi-A organic dyes with nitrostyryl triphenylamine-based structures (NTPAs) were designed and computationally studied, in which triphenylamine, carbazole, or indoline structures were used as donor and NO2 group as acceptor. The LUMOs of these dyes are more localized at the nitrostyryl moiety with almost the same energy and the HOMOs, which are orthogonal to the LUMOs, can be conveniently tuned by changing the donor structure and using different functional groups substituted on the donor. Compared with triphenylamine molecules, carbazole molecules decrease the HOMO energy of NTPA, whereas cis N-phenylindoline structure increase the HOMO energy. In addition, the exciton sizes generated by these dyes are also tuned in a range of 7.0-12.7 A. These results show that introduction of dimethylamino group on the triphenylamine moiety greatly increases the HOMO energy and prolongs the maximum absorption wavelength as well as increases the exciton size, indicating that NTPA dyes containing strong electron donating dimethylamino group on the donor part are promising candidates as sensitizers in the dye-sensitized solar cell applications. The results of the structural and spectral properties show good correlation with the experimental results, which confirms that the DFT method employed in this work is an effective way to design organic small molecule based sensitizers.

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“…Due to the rapid development of molecular science, organic luminescent crystal materials have becoming one hot topic. [1][2][3][4][5][6][7][8][9][10] Different from single molecules, aggregates usually exhibit more novel properties due to the existence of multiple packing modes, which can be converted into each other by adjusting the intermolecular interactions. [11][12][13][14] Organic luminescent crystals have extremely wide application fields because they combine excellent stability, easy availability, and superior optoelectronic performance.…”

Section: Introductionmentioning

confidence: 99%

Organic luminescent crystals: role of packing structures and optical properties

Yin¹,

Pan²,

Zhang³

et al. 2023

Mater. Chem. Front.

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Progress on Exploring the Luminescent Properties of Organic Molecular Aggregates by Multiscale Modeling

Cited by 7 publications

References 82 publications

Conformational Flexibility-Controlled Piezochromic Behavior of Organic Fluorophores

Conformational Flexibility-Controlled Piezochromic Behavior of Organic Fluorophores

Tuning the HOMO Energy of the Triarylamine Molecules with Orthogonal HOMO and LUMO Using Functional Groups

Organic luminescent crystals: role of packing structures and optical properties

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