CAREER: Photovoltaic Devices with Earth-Abundant Low Dimensional Chalcogenides

University Of Alabama Tuscaloosa, Tuscaloosa AL

Investigators

Abstract

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.