Monolayer WS2 electro- and photo-luminescence enhancement by TFSI treatment

A. R. Cadore, B. L.T. Rosa, I. Paradisanos, S. Mignuzzi, D. De Fazio, E. M. Alexeev, A. Dagkli, J. E. Muench, G. Kakavelakis, S. M. Shinde, D. Yoon, S. Tongay, K. Watanabe, T. Taniguchi, E. Lidorikis, I. Goykhman, G. Soavi, A. C. Ferrari

Research output: Contribution to journalArticlepeer-review


Layered material heterostructures (LMHs) can be used to fabricate electroluminescent devices operating in the visible spectral region. A major advantage of LMH-based light emitting diodes (LEDs) is that electroluminescence (EL) emission can be tuned across that of different exciton complexes (e.g. biexcitons, trions, quintons) by controlling the charge density. However, these devices have an EL quantum efficiency as low as ∼10−4%. Here, we show that the superacid bis-(triuoromethane)sulfonimide (TFSI) treatment of monolayer WS2-LEDs boosts EL quantum efficiency by over one order of magnitude at room temperature. Non-treated devices emit light mainly from negatively charged excitons, while the emission in treated ones predominantly involves radiative recombination of neutral excitons. This paves the way to tunable and efficient LMH-based LEDs.

Original languageEnglish
Article number025017
Journal2D Materials
Issue number2
StatePublished - Apr 2024


  • electroluminescence
  • layered materials heterostructures
  • transition metal dichalcogenides

All Science Journal Classification (ASJC) codes

  • General Chemistry
  • Condensed Matter Physics
  • Mechanics of Materials
  • Mechanical Engineering
  • General Materials Science


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