Accelerated Carrier Relaxation through Reduced Coulomb Screening in Two-Dimensional Halide Perovskite Nanoplatelets.

ABSTRACT: For high-speed optoelectronic applications relying on fast relaxation or energy-transfer mechanisms, understanding of carrier relaxation and recombination dynamics is critical. Here, we compare the differences in photoexcited carrier dynamics in two-dimensional (2D) and quasi-three-dimensional (quasi-3D) colloidal methylammonium lead iodide perovskite nanoplatelets via differential transmission spectroscopy. We find that the cooling of excited electron-hole pairs by phonon emission progresses much faster and is intensity-independent in the 2D case. This is due to the low dielectric surrounding of the thin perovskite layers, for which the Fröhlich interaction is screened less efficiently leading to higher and less density-dependent carrier-phonon scattering rates. In addition, rapid dissipa

SUBMITTER: Hintermayr VA 

PROVIDER: S-EPMC6202634 | biostudies-literature | 2018 Oct

REPOSITORIES: biostudies-literature