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Photoinitiated charge transfer in tailor-made molecules studied with 100 kilohertz two-dimensional white-Light spectroscopy

使用 100 kHz 二维白光光谱研究定制分子中的光引发电荷转移

基本信息

批准号：
1665110
负责人：
Martin Zanni
金额：
$ 45.2万
依托单位：
University of Wisconsin-Madison
依托单位国家：
美国
项目类别：
Standard Grant
财政年份：
2017
资助国家：
美国
起止时间：
2017-07-15 至 2020-06-30
项目状态：
已结题

来源：
https://www.nsf.gov/awardsearch/showAward?AWD_ID=1665110&HistoricalAwards=false
关键词：
Photoinitiated charge transfer tailor made

项目摘要

In this project funded by the Chemical Structure Dynamics and Mechanism-A (CSDM-A) program of the Chemistry Division, Professor Martin T. Zanni of the University of Wisconsin-Madison is studying charge transfer in tailor-made molecules using a new technique called two-dimensional white-light (2D WL) spectroscopy. Charge transfer processes play a central role in chemistry, such as for delivering electrons to speed up chemical reactions. A detailed understanding of charge transfer is difficult, because one must know the structures of the molecules, how much energy they contain, and how fast the electrons transfer from one place to another. Professor Zanni is addressing this challenge by studying a series of tailor-made molecules with well-defined and systematically varied structures. This series of molecules is being synthesized by the research group of Professor Michael Wasielewski at Northwestern University. Since these molecules absorb light of different colors, Professor Zanni uses white light spectroscopy to study the energy levels of the molecules and the rates of charge transfer. White light is a combination of all other colors of visible light. Absorption spectra are graphic descriptions of how atoms or molecules absorb light of different colors (wavelengths). By exciting the molecules with brief light pulses separated from each other by a few hundred femtoseconds (a femtosecond is one quadrillionth of a second), Professor Zanni is able to generate two-dimensional spectra, which look like topographical maps, and provide clues about how charge and energy are moving within or between molecules. The insights provided by this research may advance our understanding of charge transfer processes in living systems, and may have implications for the design of materials relevant to solar energy technologies. Professor Zanni and his group are involved in various activities focused on the public science education. They give presentations at the Wingra Elementary School Science Night and host an Research Experiences for Undergraduates (REU) high school teacher as part of their research dissemination plan. Professor Zanni and his group have also designed and prepared a televised lecture for Wisconsin Public Television on transitioning technologies from university research into the commercial sphere.A series of custom-made molecules are being studied by the Zanni research group using a 2D WL spectroscopy technique developed by this group. The series of molecules, prepared by the Wasielewski group, is designed to vary the electronic couplings and charge-transfer character in a systematic way. One set of compounds are caged complexes designed to capture and deliver multiple charges for use in multielectron redox reactions. Another set are bridged dimers of terrylene and perylene diimide, held in specific geometries. The bridged dimer systems have systematically controlled electronic couplings relevant to charge transfer in singlet fission. Two dimensional WL spectroscopy uses continuum generation for the pulse sequence, creating spectra that span nearly the entire visible and near-IR region of the spectrum. White-light is much weaker than the output of an optical parametric amplifier (OPA), and so the spectrometer is paired to a 100 kHz laser source and a shot-to-shot pulse shaper. With a broad spectral range and high signal-to-noise, this 2D WL spectrometer is well-suited for studying Professor Wasielewski's compounds. Initial 2D WL spectra contain cross peaks that reveal charge-transfer transitions that were previously unobserved in absorption spectra, uncovering the photophysical pathway for charge transfer in these compounds. The sensitivity of this 100 kHz spectrometer is so high that the final aim of this research is to implement it as a microscopy tool to measure spatially resolved 2D WL spectra. This research may extend our understanding of charge transfer and to develop new optical technologies. The experiments made possible by the combination of these tailor-made molecules and new 2D WL spectroscopy may overcome existing challenges and extend the understanding of charge transfer in chemistry.

本研究由化学系化学结构动力学与机理-A（CSDM-A）项目资助。威斯康星大学麦迪逊分校的Zanni正在使用一种称为二维白光（2D WL）光谱学的新技术研究定制分子中的电荷转移。电荷转移过程在化学中起着核心作用，例如传递电子以加速化学反应。详细了解电荷转移是困难的，因为人们必须知道分子的结构，它们包含多少能量，以及电子从一个地方转移到另一个地方的速度。Zanni教授正在通过研究一系列具有明确定义和系统变化结构的定制分子来应对这一挑战。这一系列分子由西北大学Michael Wasielewski教授的研究小组合成。由于这些分子吸收不同颜色的光，Zanni教授使用白色光谱学来研究分子的能级和电荷转移的速率。白色光是所有其他颜色的可见光的组合。吸收光谱是原子或分子如何吸收不同颜色（波长）的光的图形描述。通过用彼此相隔几百飞秒的短暂光脉冲激发分子（飞秒是一秒的千万亿分之一），Zanni教授能够产生二维光谱，看起来像地形图，并提供有关电荷和能量如何在分子内或分子之间移动的线索。这项研究提供的见解可能会促进我们对生命系统中电荷转移过程的理解，并可能对太阳能技术相关材料的设计产生影响。Zanni教授和他的团队参与了各种专注于公共科学教育的活动。作为研究传播计划的一部分，他们在Wingra小学科学之夜进行演讲，并主持本科生（REU）高中教师的研究经历。Zanni教授和他的小组还为威斯康星州公共电视台设计并准备了一个电视演讲，介绍从大学研究到商业领域的技术过渡。Zanni研究小组正在使用该小组开发的2D WL光谱技术研究一系列定制分子。由Wasielewski小组制备的一系列分子被设计成以系统的方式改变电子耦合和电荷转移特性。一组化合物是笼状复合物，设计用于捕获和传递多个电荷以用于多电子氧化还原反应。另一组是三萘嵌苯和二萘嵌苯二酰亚胺的桥接二聚体，以特定的几何形状保持。桥接二聚体系统有系统地控制电子耦合有关的单重态裂变中的电荷转移。二维WL光谱学使用连续谱产生脉冲序列，产生跨越光谱的几乎整个可见光和近红外区域的光谱。白光比光学参量放大器（OPA）的输出弱得多，因此光谱仪与100 kHz激光源和一个单脉冲整形器配对。这款2D WL光谱仪具有宽光谱范围和高信噪比，非常适合研究Wasielewski教授的化合物。初始2D WL光谱包含交叉峰，其揭示了先前在吸收光谱中未观察到的电荷转移跃迁，揭示了这些化合物中电荷转移的物理化学途径。这100 kHz光谱仪的灵敏度是如此之高，本研究的最终目的是实现它作为一个显微镜工具来测量空间分辨的二维WL光谱。这项研究可能会扩展我们对电荷转移的理解，并开发新的光学技术。通过这些定制分子和新的2D WL光谱的结合，实验可能克服现有的挑战，并扩展对化学中电荷转移的理解。

项目成果

期刊论文数量（9）

专著数量（0）

科研奖励数量（0）

会议论文数量（0）

专利数量（0）

Impact of non-equilibrium molecular packings on singlet fission in microcrystals observed using 2D white-light microscopy

DOI：
10.1038/s41557-019-0368-9
发表时间：
2020-01-01
期刊：
NATURE CHEMISTRY
影响因子：
21.8
作者：
Jones, Andrew C.;Kearns, Nicholas M.;Zanni, Martin T.
通讯作者：
Zanni, Martin T.

Two-Dimensional Electronic Spectroscopy Reveals Excitation Energy-Dependent State Mixing during Singlet Fission in a Terrylenediimide Dimer

DOI：
10.1021/jacs.8b08627
发表时间：
2018-12-26
期刊：
JOURNAL OF THE AMERICAN CHEMICAL SOCIETY
影响因子：
15
作者：
Mandal, Aritra;Chen, Michelle;Wasielewski, Michael R.
通讯作者：
Wasielewski, Michael R.

Enhancing the signal strength of surface sensitive 2D IR spectroscopy

DOI：
10.1063/1.5065511
发表时间：
2019-01-14
期刊：
JOURNAL OF CHEMICAL PHYSICS
影响因子：
4.4
作者：
Petti, Megan K.;Ostrander, Joshua S.;Zanni, Martin T.
通讯作者：
Zanni, Martin T.

Dual spectral phase and diffraction angle compensation of a broadband AOM 4-f pulse-shaper for ultrafast spectroscopy

用于超快光谱的宽带 AOM 4-f 脉冲整形器的双光谱相位和衍射角补偿

DOI：
10.1364/oe.27.037236
发表时间：
2019
期刊：
Optics Express
影响因子：
3.8
作者：
Jones, Andrew C.;Kunz, Miriam Bohlmann;Tigges-Green, Isabelle;Zanni, Martin T.
通讯作者：
Zanni, Martin T.

Heterogeneous Amyloid β-Sheet Polymorphs Identified on Hydrogen Bond Promoting Surfaces Using 2D SFG Spectroscopy