Excitonic Energy Transfer in Heterostructures of Quasi-2D Perovskite and Monolayer WS2

Qi Zhang; Eric Linardy; Xinyun Wang; Goki Eda

doi:10.1021/acsnano.0c03893

Excitonic Energy Transfer in Heterostructures of Quasi-2D Perovskite and Monolayer WS₂

ACS Nano. 2020 Sep 22;14(9):11482-11489. doi: 10.1021/acsnano.0c03893. Epub 2020 Aug 17.

Authors

Qi Zhang¹, Eric Linardy^{1

2}, Xinyun Wang^{1

2}, Goki Eda^{1

2

3}

Affiliations

¹ Department of Physics, National University of Singapore, 2 Science Drive 3, Singapore 117542.
² Centre for Advanced 2D Materials, National University of Singapore, 6 Science Drive 2, Singapore 117546.
³ Department of Chemistry, National University of Singapore, 3 Science Drive 3, Singapore 117543.

PMID: 32790345
DOI: 10.1021/acsnano.0c03893

Abstract

Quasi-two-dimensional (2D) organic-inorganic hybrid perovskite is a re-emerging material with strongly excitonic absorption and emission properties that are attractive for photonics and optoelectronics. Here we report the experimental observation of excitonic energy transfer (ET) in van der Waals heterostructures consisting of quasi-2D hybrid perovskite (C₆H₅C₂H₄NH₃)₂PbI₄ (PEPI) and monolayer WS₂. Photoluminescence excitation spectroscopy reveals a distinct ground exciton resonance feature of perovskite, evidencing ET from perovskite to WS₂. We find unexpectedly high photoluminescence enhancement factors of up to ∼8, which cannot be explained by single-interface ET. Our analysis reveals that interlayer ET across the bulk of the layered perovskite also contributes to the large enhancement factor. Further, from the weak temperature dependence of the lower-limit ET rate, which we found to be ∼3 ns^-1, we conclude that the Förster-type mechanism is responsible.

Keywords: 2D perovskite; heterostructure; nonradiative energy transfer; photoluminescence excitation; tungsten disulfide.