Supramolecular Lattice Deformation and Exciton Trapping in Nanotubular J-Aggregates
Supramolecular Lattice Deformation and Exciton Trapping in Nanotubular J-Aggregates
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纳米管 J-聚集体中的超分子晶格变形和激子捕获
DOI：
10.1021/acs.jpcc.1c10540
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发表时间：
2022
期刊：
影响因子：
--
通讯作者：
Bawendi, Moungi G.
中科院分区：
文献类型：
--
作者：
Klein, Megan D.;Shulenberger, Katherine E.;Barotov, Ulugbek;Šverko, Tara;Bawendi, Moungi G.
激子和分子振动模式之间的相互作用限制了有机分子聚集体中激子离域的程度和能量输运速度，降低了它们在许多光学器件应用中的性能。这种耦合导致激子自捕获，从而改变了它们的发射行为。某些两亲性菁染料形成纳米管聚集体，表现出高的激子输运率，并且没有激子和分子振动模式之间的耦合。然而，在持续的光照下，这些聚集体经历了光亮(PB)，并显示出量子产率的翻倍。我们在低照度下通过光谱和时间分辨的光致发光(PL)测量研究了这种可逆的PB过程。我们观察到激子寿命延长而没有相应的光谱变化。此外，广角X射线散射测量表明，聚集体结构在PB后发生了变化。我们提出了一个通过大极化子形成的PB模型，通过与超分子振动的相互作用而不是通常在其他聚集体中观察到的分子内振动来捕获或屏蔽这些长相干长度的激子。然后，这些激子就不能访问非辐射复合位置，从而导致观察到的量子产额的增加。晶格变形在发射后持续存在，并随时间积累，导致聚集体在持续照明下变亮。我们通过温度、颜色和基质相关的光致发光测量来支持这一模型，并表明该模型正确地预测了添加FRET猝灭剂时观察到的变化。最后，我们展示了通过用二氧化硅外壳对聚集体进行硬化来控制PB行为，从而潜在地使利用具有显著更高光致发光量子产率的分子聚集体开发长期光亮器件成为可能。
Interactions between excitons and molecular vibrational modes limit the extent of exciton delocalization and rate of energy transport in organic molecular aggregates, diminishing their performance in many optical device applications. This coupling leads to exciton self-trapping and subsequently changes their emission behavior. Certain amphiphilic cyanine dyes form nanotubular aggregates that demonstrate high exciton transport rates and show no such coupling between excitons and molecular vibrational modes. However, under sustained illumination these aggregates undergo photobrightening (PB) and can show a doubling in quantum yield. We investigate this reversible PB process through spectral- and time-resolved photoluminescence (PL) measurements under low illumination intensities. We observe lengthening exciton lifetimes with no corresponding spectral change. Furthermore, wide-angle X-ray scattering measurements show a change in the aggregate structure following PB. We propose a model of PB through large polaron formation, leading to trapping or shielding of these long coherence length excitons through interactions with supramolecular vibrations rather than the intramolecular vibrations typically observed in other aggregates. These excitons are then less able to access nonradiative recombination sites, which leads to the observed increase in quantum yield. The lattice deformations persist after emission and accumulate over time, resulting in brightening of the aggregate under sustained illumination. We support this model through temperature-, color-, and matrix-dependent photoluminescence measurements and show that the model correctly predicts the changes observed upon addition of a FRET quencher. Finally, we demonstrate control over PB behavior through rigidification of the aggregate with a silica shell, potentially enabling the development of long-term-photobrightened devices utilizing molecular aggregates with significantly higher photoluminescence quantum yields.
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影响因子：
3.3
作者：
von Berlepsch, Hans;Kirstein, Stefan;Boettcher, Christoph
通讯作者：
Boettcher, Christoph
影响因子：
3.3
作者：
Peterson, Jeffrey J.;Krauss, Todd D.
通讯作者：
Krauss, Todd D.
DOI：
10.1021/acsanm.0c02189
发表时间：
2020-10
期刊：
--
影响因子：
--
作者：
Markus Hecht;Tim Schlossarek;Samrat Ghosh;Yusuke Tsutsui;A. Schmiedel;M. Holzapfel;M. Stolte;C. Lambert;S. Seki;M. Lehmann;F. Würthner
通讯作者：
Markus Hecht;Tim Schlossarek;Samrat Ghosh;Yusuke Tsutsui;A. Schmiedel;M. Holzapfel;M. Stolte;C. Lambert;S. Seki;M. Lehmann;F. Würthner
分散在聚合物薄膜中的高度定向 J 聚集体的新制造方法
DOI：
--
发表时间：
1993
期刊：
影响因子：
--
作者：
K. Misawa;H. Ono;K. Minoshima;Takayoshi Kobayashi
通讯作者：
Takayoshi Kobayashi
用于光收集和能量传输的量子点/J-聚集体混合薄膜。
DOI：
--
发表时间：
2010
期刊：
Nano letters (Print)
影响因子：
--
作者：
Brian J. Walker;V. Bulović;M. Bawendi
通讯作者：
M. Bawendi