Accelerated Hot-Carrier Cooling in MAPbI3 Perovskite by Pressure-Induced Lattice Compression

Hot-carrier cooling (HCC) in metal halide perovskites above the Mott transition is significantly slower than in conventional semiconductors. This effect is commonly attributed to a hot-phonon bottleneck, but the influence of the lattice properties on the HCC behavior is poorly understood. Using pressure-dependent transient absorption spectroscopy, we find that at an excitation density below the Mott transition, pressure does not affect the HCC. On the contrary, above the Mott transition, HCC in methylammonium lead iodide is around 2-3 times faster at 0.3 GPa than at ambient pressure. Our electron-phonon coupling calculations reveal similar to 2-fold stronger electron-phonon coupling for the inorganic cage mode at 0.3 GPa. However, our experiments reveal that pressure promotes faster HCC only above the Mott transition. Altogether, these findings suggest a change in the nature of excited carriers above the Mott transition threshold, providing insights into the electronic behavior of devices operating at such high charge-carrier densities.

Automated summary

Through pressure-dependent transient absorption spectroscopy experiments, it was found that pressure has an influence on hot-carrier cooling behavior in metal halide perovskites, with the upper limit above the Mott transition. The results indicate that above this transition, pressure can promote faster hot-carrier cooling, suggesting a change in the electronic behavior of devices at high charge-carrier densities.