Fig. 1. Perovskite structure APbI3^[13]. (a) A⁺ is inorganic cation Cs⁺; (b) A⁺ is organic cation MA⁺

Fig. 2. Energy levels of point defects in the perovskite MAPbI₃^[24]

Fig. 3. THz complex conductivity scattering relationship of MAPbI₃ thin films at different temperatures^[26]. (a) Real part; (b) imaginary part (solid line represents Lorentzian fitting curve, and solid scatter represents experimental data)

Fig. 4. THz complex conductivity refractive relationship of MAPbI₃ film with Drude-Smith response at 15 K and 285 K^[27]. (a) (c) Real part; (b) (d) imaginary part

Fig. 5. (a) (b) Carrier density and (c) (d) mobility extracted from the complex conductivity, respectively, at 18 K and 285 K^[27]

Fig. 6. Time-resolved pump-probe spectroscopy with frequency integration (1D TRTS) ^[28]. (a) Results in MAPbI₃; (b) extracted carrier decay rates

Fig. 7. Carrier density and effective mobility of (a) over-stoichiometric Cs_1.2PbI₂Br_1.2 and (b) stoichiometric CsPbI₂Br thin films^[31]

Fig. 8. Photo-induced optical conductivity and the corresponding fitting results^[33]

Fig. 9. Ultrafast polaron formation and relaxation processes^[39]