Possible hot-phonon botteneck in studied using pump-pump-probe spectroscopy
Phys. Rev. B 113, 104308 – Published 17 March, 2026
DOI: https://doi.org/10.1103/gnv9-n9cw
Abstract
The characterization of hot phonons in metal halide perovskites has remained qualitative. Here, we define a physical quantity called “phonon blockade” to describe the retardation capability of the collective all-interacting q-state LO phonon population on carriers. We construct an effective phonon-temperature model to quantify this phonon blockade, the key features of which are confirmed by pump-pump-probe spectroscopy. This effective phonon temperature offers a universal framework for directly comparing the immediate influence of hot phonons under different materials and excitation conditions. Both model and experiment reveal a pronounced peak in the phonon blockade at approximately 0.2 ps. By precisely setting the interpulse delay to 0.2 ps in the pump-pump-probe sequence, we observed an exceptionally prolonged hot-carrier relaxation. This experiment directly correlates LO phonon accumulation with delayed cooling, revealing the core operating principle of the hot-phonon bottleneck effect in metal halide perovskites. These findings substantially advance the understanding of hot-carrier dynamics and open avenues for developing advanced perovskite-based hot-carrier solar cells.
