Great Influence of Pressure and Isotope Effects on Nonradiative Charge Loss in Hybrid Organic-Inorganic Perovskites

The intrinsic softness of hybrid organic-inorganicperovskites(HOIPs) allows their lattice and optoelectronic performance to betunable to external pressure. Using nonadiabatic (NA) molecular dynamics,we demonstrate that a mild pressure accelerates hot electron relaxationand suppresses nonradiative electron-hole recombination inCH(3)NH(3)PbI(3). Both processes are governedby NA coupling, which is enhanced between the electronic states ofthe quasi-continuous bands while is decreased between the band-edgestates by reducing the electron-hole wave function overlap.Hydrogen/deuterium isotope exchange alleviates the pressure-inducedNA coupling by increasing lattice rigidity and decreasing wave functionoverlap, slowing down both the hot electron relaxation and electron-holerecombination processes. The simulated time scales of sub-3 ps forhot electron relaxation and half nanoseconds for recombination agreewell with the experiments. The study suggests that the isotope exchangecan mitigate the pressure-caused fast losses of hot electrons andfurther prolong the charge carrier lifetime in HOIPs.

Automated summary

Using nonadiabatic molecular dynamics simulations, it is found that slight pressure can accelerate hot electron relaxation and suppress nonradiative electron-hole recombination. Hydrogen/deuterium isotope exchange can mitigate the pressure-caused fast losses of hot electrons and prolong the charge carrier lifetime in semiconducting materials.