Colloquium Series: Dr. Yanfa Yan, University of Toledo

Join us at Chapman Hall 125 for our Colloquium Series. Dr. Yanfa Yan, distinguished professor at the University of Toledo will be joining us to present his research on Defect Physics in Photovoltaic Materials
 
Research Synopsis:

Solar photovoltaic (PV) energy has been playing an increasingly important role in the world’s energy portfolio. It is becoming a key contributor in the global transition to decarbonized electricity generation. In the past few decades, a variety of PV technologies has been extensively studied and substantial progress in PV device performance has been made. However, while some PV technologies have successfully entered the market, many others have not. The market readiness of a PV technology is mostly determined by its levelized costs of electricity (LCOE) – it must be low enough so that it is competitive to the standard electricity prices in the energy market.

In this talk, I will explain why the defect physics in the absorbers dictates the LCOE of PV technologies. Specifically, I will discuss how the power conversion efficiency, manufacturing cost, and lifetime of PV technologies are critically influenced by the quality of the absorber layers and interfaces, which is governed by the properties of point and structural defects formed therein. Using the combination of nanoscale electron microscopy characterization and density-functional theory, I 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. I will also explain how taming these defects in particular PV technologies requires specific strategies, which in turn determine the LCOE. Finally, I will provide a comparison of the LCOEs of various PV technologies