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

金属卤化物钙钛矿材料由于其优越的光电性能，在太阳能电池、发光二极管、光电探测器、激光器和用于光谱伽玛射线探测和/或x射线成像的闪烁体方面的应用取得了快速进展。钙钛矿中的缺陷会限制载流子的输运并改变载流子浓度。理解和识别钙钛矿缺陷的能力是控制钙钛矿基器件性能的关键。这项合作研究旨在将光电性能与一维钙钛矿纳米晶体中的缺陷联系起来。这些纳米晶体既可以单独利用，也可以作为纳米结构材料和器件组装中的构建块。这些设备将用于能源和生物医学应用，包括光电子、光子学、传感器、催化、纳米技术和生物技术，以及其他新兴领域。因此，它将基础科学发现转化为有益于社会的有用技术。该项目为未被充分代表的女性和少数族裔本科生以及高中教师和学生提供了参与佐治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，如果存在缺陷，预计会对载流子输运行为产生显著影响，从而影响电子和光电子性质。因此，识别、理解、控制和利用钙钛矿晶体中的缺陷是至关重要的。佐治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造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，并通过利用非接触式介电力显微镜技术，通过直接成像缺陷和光学激发下的局部传输屏障，将这些钙钛矿纳米晶体的光电特性与缺陷联系起来。系统地研究这些单分散一维钙钛矿纳米晶体的光学特性和缺陷特征，有助于开发出具有理想光电性能和最小有害缺陷的高质量钙钛矿纳米材料，从而使其在光电子器件中的应用性能得到提高。该奖项反映了美国国家科学基金会的法定使命，并通过使用基金会的知识价值和更广泛的影响审查标准进行评估，被认为值得支持。

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.