Band-Edge Exciton Fine Structure and Exciton Recombination Dynamics in Single Crystals of Layered Hybrid Perovskites

Hong-Hua Fang, Jie Yang, Sampson Adjokatse, Eelco Tekelenburg, Machteld E. Kamminga, Herman Duim, Jianting Ye, Graeme R. Blake, Jacky Even, Maria Antonietta Loi*

*Corresponding author for this work

Research output: Contribution to journalArticleAcademicpeer-review

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Abstract

2D perovskite materials have recently reattracted intense research interest for applications in photovoltaics and optoelectronics. As a consequence of the dielectric and quantum confinement effect, they show strongly bound and stable excitons at room temperature. Here, the band-edge exciton fine structure and in particular its exciton and biexciton dynamics in high quality crystals of (PEA)2PbI4 are investigated. A comparison of bulk and surface exciton lifetimes yields a room temperature surface recombination velocity of 2 × 103 cm s−1 and an intrinsic lifetime of 185 ns. Biexciton emission is evidenced at room temperature, with a binding energy of ≈45 meV and a lifetime of 80 ps. At low temperature, exciton state splitting is observed, which is caused by the electron–hole exchange interaction. Transient photoluminescence resolves the low-lying dark exciton state, with a bright/dark splitting energy estimated to be 10 meV. This work contributes to the understanding of the complex scenario of the elementary photoexcitations in 2D perovskites.

Original languageEnglish
Article number1907979
Number of pages9
JournalAdvanced Functional Materials
Volume30
Issue number6
Early online date9-Dec-2019
DOIs
Publication statusPublished - 5-Feb-2020

Keywords

  • biexciton
  • dark exciton
  • exciton state splitting
  • layered perovskite
  • ultrafast dynamics
  • CHARGED EXCITONS
  • BINDING-ENERGY
  • BIEXCITONS
  • NANOCRYSTALS
  • PHOTOLUMINESCENCE
  • EMISSION
  • STATES

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