Title: Understanding the defect physics in halide perovskites from first principles
Speaker: Haibo Xue (Computational Materials Physics Group)
Time: Feb. 10, 2022, 10:00–11:00
Location: Online seminar (Teams)
Abstract | Halide perovskite semiconductors have outstanding optoelectronic properties. Although these perovskites are defect-tolerant electronically, defects hamper their long-term stability and cause chemical degradation. Identifying the types and concentrations of defects and their correlation with the electrical properties in experiments is challenging. Density functional theory (DFT) calculations complement experiments by predicting the key quantities such as, the abundance and the electronic nature of defects via calculating the defect formation energies and charge state transition levels. Based on an extensive comparison of a wide range of levels of theories and calculation procedures, an efficient and accurate framework is proposed and predictions are subsequently made for six primary perovskites. A comprehensive analysis and comparison of the dominant defects and major source of deep traps in different perovskites are made. These results present an important step towards a fundamental understanding of the defect physics of this material class and provide important insights for strategies in controlling defects to achieve optimal performance in optoelectronics and long-term stability of perovskites.