DOI
https://doi.org/10.25772/C22S-V196
Defense Date
2021
Document Type
Dissertation
Degree Name
Doctor of Philosophy
Department
Mechanical and Nuclear Engineering
First Advisor
Dr. Gary Tepper
Abstract
In the field of photovoltaics, scientists and researchers are working fervently to produce a combination of efficient, stable, low cost and scalable devices. Methylammonium lead trihalide perovskite has attracted intense interest due to its high photovoltaic performance, low cost, and ease of manufacture. Their high absorption coefficient, tunable bandgap, low-temperature processing, and abundant elemental constituent provide innumerable advantages over other thin film absorber materials. Since the perovskite film is the most important in the device, morphology, crystallization, compositional and interface engineering have been explored to boost its performance and stability. High temperatures necessary for crystallization of organic-inorganic hybrid perovskite films can have detrimental effects such as degradation of perovskite into other products (impurities) resulting in non-uniform optoelectronic performance across the thickness of the active layer, thus reducing photovoltaic performance. In addition, the time required for complete crystallization of the perovskite film increases dramatically at reduced annealing temperatures, making device production at lower temperatures impractical. We have produced high quality perovskite active layer films at low temperatures in the presence of supercritical carbon dioxide. Carbon dioxide above critical point: 31 degrees celsius, 1071psi, acts as a non-solvent mobilizer to significantly enhance the film crystallization rate at low temperatures. Perovskite-based solar cells with high power conversion efficiency and stability were produced by annealing the perovskite layer in the presence of supercritical fluids.
Rights
© The Author
Is Part Of
VCU University Archives
Is Part Of
VCU Theses and Dissertations
Date of Submission
5-10-2021
Included in
Chemical Engineering Commons, Electrical and Electronics Commons, Electronic Devices and Semiconductor Manufacturing Commons, Nanoscience and Nanotechnology Commons, Nanotechnology Fabrication Commons, Other Materials Science and Engineering Commons, Semiconductor and Optical Materials Commons