Uncovering Energy and Charge Transport Mechanisms in Organic-Inorganic Hybrid Perovskite Quantum Wells with Nonlinear Action Spectroscopies

在化学系化学结构、动力学和机理B(CSDM-B)计划和化学测量与成像(CMI)计划的支持下，北卡罗来纳大学教堂山分校化学系的魏友和安德鲁·莫兰正在开发二维有机-无机杂化钙钛矿(2D-OIHPs)材料，以期将其用于太阳能电池。在这些材料中，有机分子层将光激发的电子限制在无机金属卤化物层内，这种金属卤化物层被称为“量子井”。这项研究的目标是通过使用四嗪分子的衍生物来调节间隙有机层的电子结构，从而在这种基于2D-OIHP的太阳能电池中实现远程电子传输。材料的发展将通过用新开发的激光光谱仪直接测量电子速度来指导。该项目位于物理化学和材料化学的交界处。涉及K-12学生的研究生教育和外联活动是该项目的组成部分。二维有机-无机杂化钙钛矿(2D-OIHPs)是一种将有机阳离子和无机卤化物骨架交替组装成层状结构的材料，由于其独特的光电性质而受到广泛的研究。这些体系的无机相(即量子阱)的性质取决于金属-卤化物八面体堆积的数量以及与有机层的相互作用。在拟议的工作中，四嗪类化合物将被引入到2D-OIHPS中，通过改变施主-受体相互作用和相邻量子阱之间的距离来促进面外电子转移过程。该团队假设，通过将四氮杂间隔物分子的LUMO能级与量子阱的导带最小值对齐，将促进面外电子转移。除了常规技术外，该团队还将应用新开发的多维“作用光谱仪”来区分这些系统中的能量和电荷传输动力学。这项合作提案充分利用了专门从事(I)材料合成和器件制造以及(Ii)多维激光光谱仪开发和应用的研究小组的互补专业知识。该奖项反映了NSF的法定使命，并通过使用基金会的智力优势和更广泛的影响审查标准进行评估，被认为值得支持。

WIth support from the Chemical Structure, Dynamics & Mechanisms-B (CSDM-B) Program and the Chemical Measurement and Imaging (CMI) Program of the Division of Chemistry, Wei You and Andrew Moran of the Department of Chemistry at the University of North Carolina at Chapel Hill are developing two-dimensional organic-inorganic hybrid perovskite (2D-OIHPs) materials for their potential use in solar cells. In these materials, layers of organic molecules confine photoexcited electrons within inorganic metal-halide sheets termed “quantum wells.” The goal of this research is to enable long-range electron transport in such 2D-OIHP based solar cells by tuning the electronic structures of the interstitial organic layers using derivatives of tetrazine molecules. Materials developments will be guided by direct measurements of electron velocities with newly developed laser spectroscopies. The project lies at the interface of physical and materials chemistry. Graduate student education and outreach activities involving K-12 students are integral parts of this project. Two-dimensional organic-inorganic hybrid perovskites (2D-OIHPs), in which organic cations and inorganic halide frameworks are assembled in an alternating manner into a layered structure, have been intensively studied due to their unique optoelectronic properties. The inorganic phases of these systems (i.e., quantum wells) exhibit properties that depend on the number of stacked metal-halide octahedra and interactions with the organic layers. In the proposed work, derivatives of tetrazine will be incorporated into 2D-OIHPs to promote out-of-plane electron transfer processes by varying donor-acceptor interactions and distances between neighboring quantum wells. The team hypothesizes that out-of-plane electron transfer will be facilitated by aligning the LUMO levels of tetrazine spacer molecules with the conduction band minima of the quantum wells. In addition to conventional techniques, the team will apply newly developed, multidimensional “action spectroscopies” to distinguish energy and charge transport dynamics in these systems. This collaborative proposal leverages the complementary expertise of research groups who specialize in (i) materials synthesis and device fabrication as well as (ii) the development and application of multidimensional laser spectroscopies.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.