Fig. 1. Schematic diagram of solar cell structures. (a) Schematic diagram of traditional solar cell energy level structure^[35]; (b) schematic diagram of ideal hot-carrier solar cell device structure^[36]

Fig. 2. 3D perovskite type. (a) Transient absorption spectra of MAPbI_3－xCl_x film under different excitation intensities^[60]; (b) long-distance diffusion imaging of hot carriers in MAPbI₃ thin film measured by time-space resolved spectroscopy^[25]

Fig. 3. Quantum well type. (a) Normalized transient absorption kinetic curves for symmetric and asymmetric MQW^[63]; (b) hot carrier cooling lifetime of quantum wells with different layers^[67]; (c) schematic diagram of the main loss paths of hot-carrier energy in MAPbI₃ and RP perovskite^[68]

Fig. 4. Nanocrystalline type. (a) Formation kinetics of the bleaching signal for perovskite nanocrystals with different cations^[43]; (b) average cooling time for hot carriers τC1 and cooling carriers τC2 and the bandgap obtained by double exponential fitting to the cooling curves of MAPb_1－xSn_xI₃ perovskite ^[71]

Fig. 5. Hot electron extraction^[31]. (a) Energy level diagram of MAPbBr₃ nanocrystals with Bphen and the competition between hot carrier cooling and hot carrier extraction; (b) comparison of normalized transient absorption spectra of MAPbBr₃ nanocrystalline film with and without Bphen extraction layer; (c) temporal evolution of hot carrier temperature for MAPbBr₃ nanocrystalline film with or without Bphen extraction layer

Fig. 6. Hot hole extraction. (a) Normalized transient absorption spectra of CsPbI₃ in the presence and absence of P3HT molecules at a time delay of 0.3 ps^[56]; (b) kinetic curves at the bleaching peak of MAPbI₃, TiO₂-MAPbI₃, and MAPbI₃-spiro-OMeTAD ^[72]

Fig. 7. Hot carrier extraction^[73]. (a) Energy level arrangement diagram of CsPbBr₃ and BQ, PTZ molecules; contribution of the phonon vibration mode of (b) CsPbBr₃, (c) CsPbBr₃-BQ, and (d) CsPbBr₃-PTZ to the conductivity spectrum, the red points denote the real conductivity, and the blue point denote the conductivity after adding Lorentz oscillator to simulate phonon vibration, the red and blue lines indicate the corresponding fitting results

Fig. 8. Structure of internal light-emitting hot-carrier solar cell and the dynamical progress of photo-generated carriers in this device ^[82]