"Taming Defects for High Performance Thin-Film Solar Cells"
Professor Yanfa Yan - Department of Physics, University of Toledo
Host: David Ginger

Solar energy is becoming a key contributor in the global transition to decarbonized electricity generation. In the past few decades, a variety of photovoltaic (PV) technologies has been extensively studied and substantial progress in PV device performance has been made. The market readiness of PV technologies is mostly determined by their levelized costs of electricity (LCOE) ­– it must be low enough so that it is competitive to the standard electricity prices in the energy market. The LCOE is dictated by the performance of PV technologies including the power conversion efficiency and lifetime. In this talk, Prof. Yan will explain how defects impact the performance of solar cells and manufacturing costs, and he will discuss how taming defects is essential for fabricating high performance solar cells. Using the combination of nanoscale electron microscopy characterization and density-functional theory, Prof. Yan will review our understanding of defect physics in the following mainstream PV materials: Si, GaAs, CdTe, Cu(In,Ga)Se₂ (CIGS), Cu₂ZnSnSe₂ (CZTS), and halide perovskites. He will also discuss corresponding strategies for taming defects in particular PV technologies. Finally, Prof. Yan will present examples for fabricating efficient and stable CdTe, Sb₂Se₃, and perovskite thin-film solar cells.