Nonradiative Energy Transfer between Thickness-Controlled Halide Perovskite Nanoplatelets

TL;DR

This study demonstrates efficient F"orster resonance energy transfer in thickness-controlled halide perovskite nanoplatelets, enabling energy cascade structures for improved optoelectronic applications.

Contribution

It reveals how quantum confinement in CsPbBr3 nanoplatelets facilitates FRET, overcoming ion migration issues for cascaded energy transfer structures.

Findings

FRET transfer rates up to 0.99 ns^-1

FRET efficiencies nearly 70%

Successful energy transfer between different thicknesses

Abstract

Despite showing great promise for optoelectronics, the commercialization of halide perovskite nanostructure-based devices is hampered by inefficient electrical excitation and strong exciton binding energies. While transport of excitons in an energy-tailored system via F\"orster resonance energy transfer (FRET) could be an efficient alternative, halide ion migration makes the realization of cascaded structures difficult. Here, we show how these could be obtained by exploiting the pronounced quantum confinement effect in two dimensional CsPbBr3 based nanoplatelets (NPls). In thin films of NPls of two predetermined thicknesses, we observe an enhanced acceptor photoluminescence (PL) emission and a decreased donor PL lifetime. This indicates a FRET-mediated process, benefitted by the structural parameters of the NPls. We determine corresponding transfer rates up to k_FRET=0.99 ns^-1 and efficiencies of nearly \eta_FRET=70%. We also show FRET to occur between perovskite NPls of other thicknesses. Consequently, this strategy could lead to tailored, energy cascade nanostructures for improved optoelectronic devices.