Lecture Topic:

Spin-orbit Coupling Effects Involved in Photovoltaic and Light-emitting Devices from 3D to 2D Perovskites.

Lecturer:

Hu Bin

Time:

December 16, 2019 (Monday) 16:00-17:30

Place:

Lecture Hall 101, Graduate School Building, Zhongguancun Campus

Organizer:

Graduate School, School of Materials

Registration:

Log-in to WeChat enterprise of Beijing Institute of Technology— 第二课堂（The Second Lecture）— Choose No.296 in the Lecture Registration

【Lecture Information】

Organic-inorganic semiconducting perovskites have demonstrated very attractive room-temperature magneto-optical response, remarkable photovoltaic actions, color-tunable light-emitting properties, and low-threshold lasing actions, to become emerging multifunctional materials. On the other hand, organic-inorganic semiconducting perovskites possess a strong spin-orbital coupling within electrically polarizable semiconducting framework consisting of organic and inorganic components in ABX3 structure. In general, spin-orbital coupling can generate three major outcomes: (i) Rashba effect, (ii) spin mixing between different states, and (iii) electric-magnetic coupling in such hybrid perovskites. It should be pointed out that organic-inorganic semiconducting perovskites show significant orbital momentum to form a strong spin-orbital coupling with spin momentum. Therefore, using orbital momentum presents a unique mechanism to control the optoelectronic properties in such hybrid perovskites. We found that changing from 3D to 2D perovskites causes from short-range spin-spin interaction to long-distance orbital-orbital interaction, leading to distinct SOC effects on the populations on dark and bright states towards developing photovoltaic and light-emitting actions. On the other hand, we observed that the spin-orbital coupling can be changed by grain boundary polarization, leading to a convenient method to tune the spin-orbital coupling through doping and mechanical stress. Moreover, using the spin-orbital coupling presents a practical approach to remove the light-emitting loss from dark states in perovskite LEDs. In summary, this presentation will discuss the spin-orbital coupling effects involved in photovoltaic and light-emitting devices from 3D to 2D perovskites.