Collaborative Research: Correlating Optoelectronic Properties with Defects in One-Dimensional Perovskite Nanocrystals

最近的研究已经见证了金属卤化物钙钛矿材料的快速发展，其由于其上级光电性质而应用于太阳能电池、发光二极管、光电探测器、激光器和用于光谱伽马射线检测和/或X射线成像的蒸发器。钙钛矿中的缺陷可以限制电荷载流子的传输并改变载流子浓度。理解和识别钙钛矿中的缺陷的能力是控制基于钙钛矿的器件的性能的关键。这项合作研究旨在将光电特性与一维钙钛矿纳米晶体中的缺陷联系起来。这些纳米晶体可以单独开发，也可以作为组装纳米结构材料和器件的构建块。这些器件将用于能源和生物医学应用，包括光电子学、光子学、传感器、催化、纳米技术和生物技术等新兴领域。因此，它将基础科学发现转化为有益于社会的有用技术。该项目为代表性不足的女性和少数民族本科生以及高中教师和学生提供了参与格鲁吉亚理工学院和加州州立大学贝克斯菲尔德分校纳米材料研究的机会。在一维（1D）金属卤化物钙钛矿中，缺陷（如果存在的话）预期对载流子输运行为以及因此对电子和光电性质施加显著影响。因此，识别、理解、控制并可能利用钙钛矿晶体中的缺陷至关重要。格鲁吉亚理工学院和加州州立大学贝克斯菲尔德分校之间的这项合作研究旨在制作具有精确控制尺寸的一维钙钛矿纳米晶体，仔细检查其尺寸相关的光学特性，并将这些钙钛矿纳米晶体的光电特性与缺陷相关联，通过利用非接触式介电力显微镜技术直接成像缺陷和光学激发下的局部传输障碍。对这些单分散1D钙钛矿纳米晶体的光学性质和缺陷特征的系统研究使得能够开发具有所需光电性质和最小有害缺陷的高质量钙钛矿纳米材料，该奖项反映了NSF的法定使命，并通过使用基金会的知识价值和更广泛的影响审查标准。

Recent research has witnessed rapid advances in metal halide perovskite materials for applications in solar cells, light-emitting diodes, photodetectors, lasers, and scintillators for spectroscopic gamma-ray detection and/or X-ray imaging due to their superior optoelectronic properties. Defects in perovskites can limit the transport of charge carriers and change the carrier concentrations. The ability to understand and recognize defects in perovskites is the key to control the performance in perovskite-based devices. This collaborative research aims to relate optoelectronic properties with defects in one-dimensional perovskite nanocrystals. These nanocrystals can be exploited either individually or as building blocks in the assembly of nanostructured materials and devices. These devices would be used in energy and biomedical applications, including optoelectronics, photonics, sensors, catalysis, nanotechnology, and biotechnology, among other emerging areas. As such, it transitions fundamental scientific discoveries into useful technologies that benefit society. This project offers opportunities for underrepresented female and minority undergraduate students as well as high school teachers and students to participate in nanomaterials research at both Georgia Tech and California State University-Bakersfield. In one-dimensional (1D) metal halide perovskites, defects, if present, are expected to exert a pronounced influence on the carrier transport behaviors and thus the electronic and optoelectronic properties. It is therefore of crucial importance to identify, understand, control, and possibly utilize defects in perovskite crystals. This collaborative research between Georgia Tech and California State University-Bakersfield seeks to craft 1D perovskite nanocrystals with precisely controlled dimensions, scrutinize their dimension-dependent optical properties, and correlate the resulting optoelectronic properties of these perovskite nanocrystals with defects via directly imaging defects and local transport barriers under optical excitations by capitalizing on a contactless dielectric force microscopy technique. The systematic investigation into the optical properties and defect characteristics of these monodisperse 1D perovskite nanocrystals enables the development of high-quality perovskite nanomaterials with desired optoelectronic properties and minimal deleterious defects, thereby rendering their use in a gamut of optoelectronic devices with improved performance.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.