CAREER: Photovoltaic Devices with Earth-Abundant Low Dimensional Chalcogenides

非技术性：太阳提供了丰富的可再生能源，如风能、太阳能和水力发电。太阳能电池，也被称为光伏设备，直接将阳光转化为电能。效率的显著提高和成本的降低导致了太阳能的广泛采用。仍然存在限制进一步采用的问题。这些措施包括采用昂贵或有毒的原材料，以及对能源密集型高温生产过程的需求。该项目将研究一种基于低维硫化物作为吸光剂的新兴太阳能技术。这些材料土质丰富，无毒，在环境条件下暴露在阳光下稳定。它们还可以在相对较低的温度下加工，原材料消耗更少，碳足迹更少，这使得这种新兴的太阳能技术具有潜在的成本竞争力和可持续性。该项目旨在通过先进的器件工程，显著提高基于低维硫化物的太阳能电池的效率。其目的是为这项新开发的太阳能技术商业化铺平道路，以提供更多负担得起的太阳能电力。该项目将通过与当地小学的长期伙伴关系影响社区。国际和平协会将接触年轻学生，介绍和促进清洁能源概念和太阳能技术。国际太阳能协会还将参加为当地中学教师举办的校园材料夏令营，举办入门讲座和提供太阳能技术的动手演示。然后，教师可以在他们的家庭学校实施这些课程，以吸引更多的学生，特别是那些来自少数族裔和代表性不足的群体的学生，从事科学和工程职业。该项目由电气、通信和网络系统司的电子、光子学和磁性设备计划和综合行动办公室的刺激竞争研究(EPSCoR)计划联合资助。技术：该项目的目标是了解一种基于地球上丰富的低维非立方硫化物吸收体的新型薄膜光伏(PV)器件的电子和光子特性，以获得高效、可持续和负担得起的太阳能。多晶低维硫化物吸收材料具有各向异性原子链和本质上良性的晶界，这提供了独特的各向异性载流子输运行为和极大的晶界缺陷容忍度。该项目将解决材料和器件方面的巨大挑战，以实现高性能、低维度的硫系化合物光伏器件。(1)了解低维硫化物吸收层的各向异性生长机制，以及它们对原子链中载流子输运和器件性能的影响；(2)通过合金化的方法来调整低维硫化物吸收层的带隙，以最大化光电压，优化带隙，最小化光电流损失；(3)利用第一性原理密度泛函理论计算指导理论预测，设计低维硫系光伏器件中的缺陷和界面，以减少载流子复合位置，增加载流子提取；(4)进行非本征掺杂工程，提高低维硫系化合物光伏器件的光生载流子密度和载流子寿命。从根本上讲，本项目将阐明低维硫系化合物光伏器件中吸波材料微结构、光生载流子传输特性和器件性能之间的关系。最终，这个拟议的项目将为下一代高效低成本薄膜光伏技术的未来发展铺平道路。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。

Nontechnical:The sun provides abundant sources of renewable energy such as wind, solar, and hydro power. Solar cells, also known as photovoltaic devices, directly convert sunlight into electricity. Dramatic efficiency improvements and cost reductions have led to widespread adoption of solar power. There are still problems that limit further adoption. These include incorporation of expensive or toxic raw materials as well as the need for energy intensive, high temperature production processes. This project will investigate an emerging solar technology based on low dimensional chalcogenides as light absorbers. These materials are earth abundant, non-toxic and stable upon exposure to sunlight under ambient conditions. They can also be processed at relatively low temperatures with fewer raw materials consumption and less carbon footprint, making this emerging solar technology potentially cost-competitive and sustainable. This project aims to significantly improve the efficiency of solar cells based on low-dimensional chalcognides through advanced device engineering. The aim is to pave the way to commercialize this newly developed solar technology to provide more affordable solar electricity. This project will impact the community through a long-term partnership with local elementary schools. The PI will reach out to young students to introduce and foster clean energy concepts and solar technologies. The PI will also participate in an on-campus material summer camp for the local secondary school teachers, giving introduction lectures and providing hands-on demonstrations of solar technologies. Teachers can then implement these lessons in their home schools to attract more students, especially those from minority and underrepresented groups, to pursue science and engineering careers. This project is jointly funded by the Electronics, Photonics, and Magnetic Devices program of the Division of Electrical, Communications, and Cyber Systems and the Established Program to Stimulate Competitive Research (EPSCoR) program of the Office of Integrative Activities.Technical:The objective of this project is to understand the electronic and photonic properties of a new class of thin-film photovoltaic (PV) devices based on earth-abundant low-dimensional noncubic chalcogenide absorbers to achieve highly efficient, sustainable, and affordable solar energy. Polycrystalline low dimensional chalcogenide absorbers possess anisotropic atomic chains and intrinsically benign grain boundaries, which provide unique anisotropic carrier transport behaviors and great grain boundary defect tolerance. Considerable fundamental material and device challenges will be addressed in this project to achieve high-performance low dimensional chalcogenides based PV devices. The following four tasks with a combination of device-level characterization will be carried out: (1) understand the anisotropic growth mechanisms of the low dimensional chalcogenide absorbers layer, and how they impact the carrier transport in the atomic chains and device performance; (2) tailor bandgap of low dimensional chalcogenide absorbers by the alloying approach to maximize the photovoltage with optimized bandgap and minimize the photocurrent loss; (3) engineer defects and interfaces in the low dimensional chalcogenides based PV devices to reduce the carrier recombination sites and increase carrier extraction with a guide of theoretical prediction using first-principle density functional theory calculation; (4) conduct extrinsic doping engineering to increase the photogenerated carrier density and carrier lifetime of the low dimensional chalcogenides based PV devices. Fundamentally, this project will elucidate the relationship between absorbers material microstructure, photogenerated carrier transport properties, and device performance in low dimensional chalcogenide-based PV devices. Eventually, this proposed project will pave the way for the future development of next-generation high-efficiency low-cost thin film PV technologies.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.