Exciton Polaritons of Halide Perovskite Semiconductor Crystals
speaker: Qing Zhang
place: Room W563, Physics building, Peking University
time: 4:00pm, Sept. 30, 2020 (Wednesday)


Recently, metal-halide perovskite semiconductors have attracted tremendous attentions owing to their promising potentials for the next generation information and optoelectronic functional devices. Besides, benefitted from the large exciton oscillator strength and binding energy, pervoskites provide an ideal platform to explore the exciton polaritons (EPs), a quasi-particle in strong coupling regime, and their condensation at room temperature1. In this literature, I will present our recent progresses on exploring EPs in halide perovskite and its correlated role in continuous wave (CW) pumped microlaser. In 2018, we firstly designed a MAPbBr3 nanowire-SiO2-Ag microcavity structure to introduce the surface plasmon polariton, which effectively increased the number of localized oscillators and further enhanced the Rabi splitting energy to ~564 meV. Latterly, we explored the propagating behaviors of EPs and the dielectric properties in CsPbBr3 nanowire at room temperature. It suggests the present of EPs enhances the group refractive index (ng) and optical absorption coefficient compared with bulk counterparts3. Besides, ng could reach 43.7 as temperature drops, which significantly increases the mode confinement factor, reduces the optical losses, and thus lowers the lasing threshold. Eventually, we realized CW pumped green microlaser in ultrathin CsPbBr3 nanoribbons on sapphire substrate4. In the last part of this talk, I will prospect the future research interests of EPs in perovskite crystals.

1. R. Su, Q. Xiong* et al., Observation of exciton polariton condensation in a perovskite lattice at room temperature. Nat. Phys. 16, 301–306 (2020).
2. Q. Shang, Q. Zhang* et al., Surface Plasmon Enhanced Strong Exciton–Photon Coupling in Hybrid Inorganic–Organic Perovskite Nanowires. Nano Lett. 18, 3335-3343 (2018).
3. Q. Shang, Q. Zhang* et al., Enhanced Optical Absorption and Slowed Light of Reduced-Dimensional CsPbBr3 Nanowire Crystal by Exciton–Polariton. Nano Lett. 20, 1023-1032 (2020).
4. Q. Shang, Q. Zhang* et al., Role of the Exciton–Polariton in a Continuous-Wave Optically Pumped CsPbBr3 Perovskite Laser, Nano Lett. 20, 6636–6643 (2020).