Exceeding 100 µs Charge Carrier Separation in Perovskite Mediated by Rhodamine 6G

Partha Maity, Rounak Naphade, Luis Gutiérrez-Arzaluz, Sarvarkhodzha Nematulloev, Simil Thomas, Wasim J. Mir, Khursand E. Yorov, Husam N. Alshareef, Osman M. Bakr, Omar F. Mohammed*

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

1 Scopus citations


Halide perovskite colloidal nanocrystals (NCs) have enabled considerable progress in light conversion applications. However, the presence of unavoidable defect states and phase transition effects can accelerate undesirable rapid charge recombination of the photogenerated charge carriers. To address this issue, chromophores with an anchoring moiety are often used to modify the surface of the NCs, promoting prolonged charge separation through electron or energy transfer processes for optoelectronic applications. Here, steady-state and time-resolved spectroscopy methods are combined with density functional theory (DFT) calculations to explore and decipher the excited-state interaction in colloidal CsPbX3 (X = Br, I) NCs with a rhodamine 6G (Rh6G) hybrid assembly. The results show that Rh6G dimerizes even at low concentrations, as evidenced by DFT calculations. The binding of Rh6G on the NC surface is confirmed by FTIR and NMR spectroscopy techniques. In addition, transient absorption spectroscopy reveals directional sub-ps electron transfer from Rh6G to CsPbI3 NCs, whereas energy transfer occurs from CsPbBr3 to Rh6G, which ultimately recombines in the µs time regime. The findings highlight the simplest and most practical approaches for studying and tailoring the excited-state interaction in colloidal perovskite NCs and chromophore assembly.

Original languageEnglish (US)
Article number2300941
JournalAdvanced Optical Materials
Issue number8
StateAccepted/In press - 2023

Bibliographical note

Funding Information:
This work was supported by the King Abdullah University of Science and Technology (KAUST). For computer time, this research used the resources of the Supercomputing Laboratory at King Abdullah University of Science & Technology (KAUST) in Thuwal, Saudi Arabia.

Publisher Copyright:
© 2023 Wiley-VCH GmbH.


  • delayed charge recombination
  • electron and energy transfer
  • lead halide perovskites
  • Rhodamine 6G
  • transient absorption spectroscopy

ASJC Scopus subject areas

  • Electronic, Optical and Magnetic Materials
  • Atomic and Molecular Physics, and Optics


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