Tian Xuesong, Fang Qiu, Long Run, Fang Wei-Hai
College of Chemistry, Key Laboratory of Theoretical & Computational Photochemistry of Ministry of Education, Beijing Normal University, Beijing 100875, P. R. China.
J Phys Chem Lett. 2023 Aug 17;14(32):7134-7140. doi: 10.1021/acs.jpclett.3c01776. Epub 2023 Aug 3.
The intrinsic softness of hybrid organic-inorganic perovskites (HOIPs) allows their lattice and optoelectronic performance to be tunable to external pressure. Using nonadiabatic (NA) molecular dynamics, we demonstrate that a mild pressure accelerates hot electron relaxation and suppresses nonradiative electron-hole recombination in CHNHPbI. Both processes are governed by NA coupling, which is enhanced between the electronic states of the quasi-continuous bands while is decreased between the band-edge states by reducing the electron-hole wave function overlap. Hydrogen/deuterium isotope exchange alleviates the pressure-induced NA coupling by increasing lattice rigidity and decreasing wave function overlap, slowing down both the hot electron relaxation and electron-hole recombination processes. The simulated time scales of sub-3 ps for hot electron relaxation and half nanoseconds for recombination agree well with the experiments. The study suggests that the isotope exchange can mitigate the pressure-caused fast losses of hot electrons and further prolong the charge carrier lifetime in HOIPs.
